summaryrefslogtreecommitdiff
path: root/merge-recursive.c
blob: 36948eafb750284551a3748405135a685ddba2ff (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
3276
3277
3278
3279
3280
3281
3282
3283
3284
3285
3286
3287
3288
3289
3290
3291
3292
3293
3294
3295
3296
3297
3298
3299
3300
3301
3302
3303
3304
3305
3306
3307
3308
3309
3310
3311
3312
3313
3314
3315
3316
3317
3318
3319
3320
3321
3322
3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
3378
3379
3380
3381
3382
3383
3384
3385
3386
3387
3388
3389
3390
3391
3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
3405
3406
3407
3408
3409
3410
3411
3412
3413
3414
3415
3416
3417
3418
3419
3420
3421
3422
3423
3424
3425
3426
3427
3428
3429
3430
3431
3432
3433
3434
3435
3436
3437
3438
3439
3440
3441
3442
3443
3444
3445
3446
3447
3448
3449
3450
3451
3452
3453
3454
3455
3456
3457
3458
3459
3460
3461
3462
3463
3464
3465
3466
3467
3468
3469
3470
3471
3472
3473
3474
3475
3476
3477
3478
3479
3480
3481
3482
3483
3484
3485
3486
3487
3488
3489
3490
3491
3492
3493
3494
3495
3496
3497
3498
3499
3500
3501
3502
3503
3504
3505
3506
3507
3508
3509
3510
3511
3512
3513
3514
3515
3516
3517
3518
3519
3520
3521
3522
3523
3524
3525
3526
3527
3528
3529
3530
3531
3532
3533
3534
3535
3536
3537
3538
3539
3540
3541
3542
3543
3544
3545
3546
3547
3548
3549
3550
3551
3552
3553
3554
3555
3556
3557
3558
3559
3560
3561
3562
3563
3564
3565
3566
3567
3568
3569
3570
3571
3572
3573
3574
3575
3576
3577
3578
3579
3580
3581
3582
3583
3584
3585
3586
3587
3588
3589
3590
3591
3592
3593
3594
3595
3596
3597
3598
3599
3600
3601
3602
3603
3604
3605
3606
3607
3608
3609
3610
3611
3612
3613
3614
3615
3616
3617
3618
3619
3620
3621
3622
3623
3624
3625
3626
3627
3628
3629
3630
3631
3632
3633
3634
3635
3636
3637
3638
3639
3640
3641
3642
3643
3644
3645
3646
3647
3648
3649
3650
3651
3652
3653
3654
3655
3656
3657
3658
3659
3660
3661
3662
3663
3664
3665
3666
3667
3668
3669
3670
3671
3672
3673
3674
3675
3676
3677
3678
3679
3680
3681
3682
3683
3684
3685
3686
3687
3688
3689
3690
3691
3692
3693
3694
3695
3696
3697
3698
3699
3700
3701
3702
3703
3704
3705
3706
3707
3708
3709
3710
3711
3712
3713
3714
3715
3716
3717
3718
3719
3720
3721
3722
3723
3724
3725
3726
3727
3728
3729
3730
3731
3732
3733
3734
3735
3736
3737
3738
3739
3740
3741
3742
3743
3744
3745
3746
3747
3748
3749
3750
3751
3752
3753
3754
3755
3756
3757
3758
3759
3760
3761
3762
3763
3764
3765
3766
3767
3768
3769
3770
3771
3772
3773
3774
3775
3776
3777
3778
3779
3780
3781
3782
3783
3784
3785
3786
3787
3788
3789
3790
3791
3792
3793
3794
3795
3796
3797
3798
3799
3800
3801
3802
3803
3804
3805
3806
3807
3808
3809
3810
3811
3812
3813
3814
3815
3816
3817
3818
3819
3820
3821
3822
3823
3824
3825
3826
3827
3828
3829
3830
3831
3832
3833
3834
3835
3836
3837
3838
3839
3840
3841
3842
3843
3844
3845
3846
3847
3848
3849
3850
3851
3852
3853
3854
3855
3856
3857
3858
3859
3860
3861
3862
3863
3864
3865
3866
3867
3868
3869
3870
3871
3872
3873
3874
3875
3876
3877
3878
3879
3880
3881
3882
3883
3884
3885
3886
3887
3888
3889
3890
3891
3892
3893
3894
3895
3896
3897
3898
3899
3900
3901
3902
3903
3904
/*
 * Recursive Merge algorithm stolen from git-merge-recursive.py by
 * Fredrik Kuivinen.
 * The thieves were Alex Riesen and Johannes Schindelin, in June/July 2006
 */
#include "cache.h"
#include "merge-recursive.h"
 
#include "advice.h"
#include "alloc.h"
#include "attr.h"
#include "blob.h"
#include "builtin.h"
#include "cache-tree.h"
#include "commit.h"
#include "commit-reach.h"
#include "config.h"
#include "diff.h"
#include "diffcore.h"
#include "dir.h"
#include "ll-merge.h"
#include "lockfile.h"
#include "object-store.h"
#include "repository.h"
#include "revision.h"
#include "string-list.h"
#include "submodule.h"
#include "tag.h"
#include "tree-walk.h"
#include "unpack-trees.h"
#include "xdiff-interface.h"
 
struct merge_options_internal {
	int call_depth;
	int needed_rename_limit;
	struct hashmap current_file_dir_set;
	struct string_list df_conflict_file_set;
	struct unpack_trees_options unpack_opts;
	struct index_state orig_index;
};
 
struct path_hashmap_entry {
	struct hashmap_entry e;
	char path[FLEX_ARRAY];
};
 
static int path_hashmap_cmp(const void *cmp_data,
			    const struct hashmap_entry *eptr,
			    const struct hashmap_entry *entry_or_key,
			    const void *keydata)
{
	const struct path_hashmap_entry *a, *b;
	const char *key = keydata;
 
	a = container_of(eptr, const struct path_hashmap_entry, e);
	b = container_of(entry_or_key, const struct path_hashmap_entry, e);
 
	if (ignore_case)
		return strcasecmp(a->path, key ? key : b->path);
	else
		return strcmp(a->path, key ? key : b->path);
}
 
static unsigned int path_hash(const char *path)
{
	return ignore_case ? strihash(path) : strhash(path);
}
 
/*
 * For dir_rename_entry, directory names are stored as a full path from the
 * toplevel of the repository and do not include a trailing '/'.  Also:
 *
 *   dir:                original name of directory being renamed
 *   non_unique_new_dir: if true, could not determine new_dir
 *   new_dir:            final name of directory being renamed
 *   possible_new_dirs:  temporary used to help determine new_dir; see comments
 *                       in get_directory_renames() for details
 */
struct dir_rename_entry {
	struct hashmap_entry ent;
	char *dir;
	unsigned non_unique_new_dir:1;
	struct strbuf new_dir;
	struct string_list possible_new_dirs;
};
 
static struct dir_rename_entry *dir_rename_find_entry(struct hashmap *hashmap,
						      char *dir)
{
	struct dir_rename_entry key;
 
	if (dir == NULL)
		return NULL;
	hashmap_entry_init(&key.ent, strhash(dir));
	key.dir = dir;
	return hashmap_get_entry(hashmap, &key, ent, NULL);
}
 
static int dir_rename_cmp(const void *unused_cmp_data,
			  const struct hashmap_entry *eptr,
			  const struct hashmap_entry *entry_or_key,
			  const void *unused_keydata)
{
	const struct dir_rename_entry *e1, *e2;
 
	e1 = container_of(eptr, const struct dir_rename_entry, ent);
	e2 = container_of(entry_or_key, const struct dir_rename_entry, ent);
 
	return strcmp(e1->dir, e2->dir);
}
 
static void dir_rename_init(struct hashmap *map)
{
	hashmap_init(map, dir_rename_cmp, NULL, 0);
}
 
static void dir_rename_entry_init(struct dir_rename_entry *entry,
				  char *directory)
{
	hashmap_entry_init(&entry->ent, strhash(directory));
	entry->dir = directory;
	entry->non_unique_new_dir = 0;
	strbuf_init(&entry->new_dir, 0);
	string_list_init(&entry->possible_new_dirs, 0);
}
 
struct collision_entry {
	struct hashmap_entry ent;
	char *target_file;
	struct string_list source_files;
	unsigned reported_already:1;
};
 
static struct collision_entry *collision_find_entry(struct hashmap *hashmap,
						    char *target_file)
{
	struct collision_entry key;
 
	hashmap_entry_init(&key.ent, strhash(target_file));
	key.target_file = target_file;
	return hashmap_get_entry(hashmap, &key, ent, NULL);
}
 
static int collision_cmp(const void *unused_cmp_data,
			 const struct hashmap_entry *eptr,
			 const struct hashmap_entry *entry_or_key,
			 const void *unused_keydata)
{
	const struct collision_entry *e1, *e2;
 
	e1 = container_of(eptr, const struct collision_entry, ent);
	e2 = container_of(entry_or_key, const struct collision_entry, ent);
 
	return strcmp(e1->target_file, e2->target_file);
}
 
static void collision_init(struct hashmap *map)
{
	hashmap_init(map, collision_cmp, NULL, 0);
}
 
static void flush_output(struct merge_options *opt)
{
	if (opt->buffer_output < 2 && opt->obuf.len) {
		fputs(opt->obuf.buf, stdout);
		strbuf_reset(&opt->obuf);
	}
}
 
static int err(struct merge_options *opt, const char *err, ...)
{
	va_list params;
 
	if (opt->buffer_output < 2)
		flush_output(opt);
	else {
		strbuf_complete(&opt->obuf, '\n');
		strbuf_addstr(&opt->obuf, "error: ");
	}
	va_start(params, err);
	strbuf_vaddf(&opt->obuf, err, params);
	va_end(params);
	if (opt->buffer_output > 1)
		strbuf_addch(&opt->obuf, '\n');
	else {
		error("%s", opt->obuf.buf);
		strbuf_reset(&opt->obuf);
	}
 
	return -1;
}
 
static struct tree *shift_tree_object(struct repository *repo,
				      struct tree *one, struct tree *two,
				      const char *subtree_shift)
{
	struct object_id shifted;
 
	if (!*subtree_shift) {
		shift_tree(repo, &one->object.oid, &two->object.oid, &shifted, 0);
	} else {
		shift_tree_by(repo, &one->object.oid, &two->object.oid, &shifted,
			      subtree_shift);
	}
	if (oideq(&two->object.oid, &shifted))
		return two;
	return lookup_tree(repo, &shifted);
}
 
static inline void set_commit_tree(struct commit *c, struct tree *t)
{
	c->maybe_tree = t;
}
 
static struct commit *make_virtual_commit(struct repository *repo,
					  struct tree *tree,
					  const char *comment)
{
	struct commit *commit = alloc_commit_node(repo);
 
	set_merge_remote_desc(commit, comment, (struct object *)commit);
	set_commit_tree(commit, tree);
	commit->object.parsed = 1;
	return commit;
}
 
enum rename_type {
	RENAME_NORMAL = 0,
	RENAME_VIA_DIR,
	RENAME_ADD,
	RENAME_DELETE,
	RENAME_ONE_FILE_TO_ONE,
	RENAME_ONE_FILE_TO_TWO,
	RENAME_TWO_FILES_TO_ONE
};
 
/*
 * Since we want to write the index eventually, we cannot reuse the index
 * for these (temporary) data.
 */
struct stage_data {
	struct diff_filespec stages[4]; /* mostly for oid & mode; maybe path */
	struct rename_conflict_info *rename_conflict_info;
	unsigned processed:1;
};
 
struct rename {
	unsigned processed:1;
	struct diff_filepair *pair;
	const char *branch; /* branch that the rename occurred on */
	/*
	 * If directory rename detection affected this rename, what was its
	 * original type ('A' or 'R') and it's original destination before
	 * the directory rename (otherwise, '\0' and NULL for these two vars).
	 */
	char dir_rename_original_type;
	char *dir_rename_original_dest;
	/*
	 * Purpose of src_entry and dst_entry:
	 *
	 * If 'before' is renamed to 'after' then src_entry will contain
	 * the versions of 'before' from the merge_base, HEAD, and MERGE in
	 * stages 1, 2, and 3; dst_entry will contain the respective
	 * versions of 'after' in corresponding locations.  Thus, we have a
	 * total of six modes and oids, though some will be null.  (Stage 0
	 * is ignored; we're interested in handling conflicts.)
	 *
	 * Since we don't turn on break-rewrites by default, neither
	 * src_entry nor dst_entry can have all three of their stages have
	 * non-null oids, meaning at most four of the six will be non-null.
	 * Also, since this is a rename, both src_entry and dst_entry will
	 * have at least one non-null oid, meaning at least two will be
	 * non-null.  Of the six oids, a typical rename will have three be
	 * non-null.  Only two implies a rename/delete, and four implies a
	 * rename/add.
	 */
	struct stage_data *src_entry;
	struct stage_data *dst_entry;
};
 
struct rename_conflict_info {
	enum rename_type rename_type;
	struct rename *ren1;
	struct rename *ren2;
};
 
static inline void setup_rename_conflict_info(enum rename_type rename_type,
					      struct merge_options *opt,
					      struct rename *ren1,
					      struct rename *ren2)
{
	struct rename_conflict_info *ci;
 
	/*
	 * When we have two renames involved, it's easiest to get the
	 * correct things into stage 2 and 3, and to make sure that the
	 * content merge puts HEAD before the other branch if we just
	 * ensure that branch1 == opt->branch1.  So, simply flip arguments
	 * around if we don't have that.
	 */
	if (ren2 && ren1->branch != opt->branch1) {
		setup_rename_conflict_info(rename_type, opt, ren2, ren1);
		return;
	}
 
	ci = xcalloc(1, sizeof(struct rename_conflict_info));
	ci->rename_type = rename_type;
	ci->ren1 = ren1;
	ci->ren2 = ren2;
 
	ci->ren1->dst_entry->processed = 0;
	ci->ren1->dst_entry->rename_conflict_info = ci;
	if (ren2) {
		ci->ren2->dst_entry->rename_conflict_info = ci;
	}
}
 
static int show(struct merge_options *opt, int v)
{
	return (!opt->priv->call_depth && opt->verbosity >= v) ||
		opt->verbosity >= 5;
}
 
__attribute__((format (printf, 3, 4)))
static void output(struct merge_options *opt, int v, const char *fmt, ...)
{
	va_list ap;
 
	if (!show(opt, v))
		return;
 
	strbuf_addchars(&opt->obuf, ' ', opt->priv->call_depth * 2);
 
	va_start(ap, fmt);
	strbuf_vaddf(&opt->obuf, fmt, ap);
	va_end(ap);
 
	strbuf_addch(&opt->obuf, '\n');
	if (!opt->buffer_output)
		flush_output(opt);
}
 
static void output_commit_title(struct merge_options *opt, struct commit *commit)
{
	struct merge_remote_desc *desc;
 
	strbuf_addchars(&opt->obuf, ' ', opt->priv->call_depth * 2);
	desc = merge_remote_util(commit);
	if (desc)
		strbuf_addf(&opt->obuf, "virtual %s\n", desc->name);
	else {
		strbuf_add_unique_abbrev(&opt->obuf, &commit->object.oid,
					 DEFAULT_ABBREV);
		strbuf_addch(&opt->obuf, ' ');
		if (parse_commit(commit) != 0)
			strbuf_addstr(&opt->obuf, _("(bad commit)\n"));
		else {
			const char *title;
			const char *msg = get_commit_buffer(commit, NULL);
			int len = find_commit_subject(msg, &title);
			if (len)
				strbuf_addf(&opt->obuf, "%.*s\n", len, title);
			unuse_commit_buffer(commit, msg);
		}
	}
	flush_output(opt);
}
 
static int add_cacheinfo(struct merge_options *opt,
			 const struct diff_filespec *blob,
			 const char *path, int stage, int refresh, int options)
{
	struct index_state *istate = opt->repo->index;
	struct cache_entry *ce;
	int ret;
 
	ce = make_cache_entry(istate, blob->mode, &blob->oid, path, stage, 0);
	if (!ce)
		return err(opt, _("add_cacheinfo failed for path '%s'; merge aborting."), path);
 
	ret = add_index_entry(istate, ce, options);
	if (refresh) {
		struct cache_entry *nce;
 
		nce = refresh_cache_entry(istate, ce,
					  CE_MATCH_REFRESH | CE_MATCH_IGNORE_MISSING);
		if (!nce)
			return err(opt, _("add_cacheinfo failed to refresh for path '%s'; merge aborting."), path);
		if (nce != ce)
			ret = add_index_entry(istate, nce, options);
	}
	return ret;
}
 
static inline int merge_detect_rename(struct merge_options *opt)
{
	return (opt->detect_renames >= 0) ? opt->detect_renames : 1;
}
 
static void init_tree_desc_from_tree(struct tree_desc *desc, struct tree *tree)
{
	parse_tree(tree);
	init_tree_desc(desc, tree->buffer, tree->size);
}
 
static int unpack_trees_start(struct merge_options *opt,
			      struct tree *common,
			      struct tree *head,
			      struct tree *merge)
{
	int rc;
	struct tree_desc t[3];
	struct index_state tmp_index = { NULL };
 
	memset(&opt->priv->unpack_opts, 0, sizeof(opt->priv->unpack_opts));
	if (opt->priv->call_depth)
		opt->priv->unpack_opts.index_only = 1;
	else
		opt->priv->unpack_opts.update = 1;
	opt->priv->unpack_opts.merge = 1;
	opt->priv->unpack_opts.head_idx = 2;
	opt->priv->unpack_opts.fn = threeway_merge;
	opt->priv->unpack_opts.src_index = opt->repo->index;
	opt->priv->unpack_opts.dst_index = &tmp_index;
	opt->priv->unpack_opts.aggressive = !merge_detect_rename(opt);
	setup_unpack_trees_porcelain(&opt->priv->unpack_opts, "merge");
 
	init_tree_desc_from_tree(t+0, common);
	init_tree_desc_from_tree(t+1, head);
	init_tree_desc_from_tree(t+2, merge);
 
	rc = unpack_trees(3, t, &opt->priv->unpack_opts);
	cache_tree_free(&opt->repo->index->cache_tree);
 
	/*
	 * Update opt->repo->index to match the new results, AFTER saving a
	 * copy in opt->priv->orig_index.  Update src_index to point to the
	 * saved copy.  (verify_uptodate() checks src_index, and the original
	 * index is the one that had the necessary modification timestamps.)
	 */
	opt->priv->orig_index = *opt->repo->index;
	*opt->repo->index = tmp_index;
	opt->priv->unpack_opts.src_index = &opt->priv->orig_index;
 
	return rc;
}
 
static void unpack_trees_finish(struct merge_options *opt)
{
	discard_index(&opt->priv->orig_index);
	clear_unpack_trees_porcelain(&opt->priv->unpack_opts);
}
 
static int save_files_dirs(const struct object_id *oid,
			   struct strbuf *base, const char *path,
			   unsigned int mode, int stage, void *context)
{
	struct path_hashmap_entry *entry;
	int baselen = base->len;
	struct merge_options *opt = context;
 
	strbuf_addstr(base, path);
 
	FLEX_ALLOC_MEM(entry, path, base->buf, base->len);
	hashmap_entry_init(&entry->e, path_hash(entry->path));
	hashmap_add(&opt->priv->current_file_dir_set, &entry->e);
 
	strbuf_setlen(base, baselen);
	return (S_ISDIR(mode) ? READ_TREE_RECURSIVE : 0);
}
 
static void get_files_dirs(struct merge_options *opt, struct tree *tree)
{
	struct pathspec match_all;
	memset(&match_all, 0, sizeof(match_all));
	read_tree_recursive(opt->repo, tree, "", 0, 0,
			    &match_all, save_files_dirs, opt);
}
 
static int get_tree_entry_if_blob(struct repository *r,
				  const struct object_id *tree,
				  const char *path,
				  struct diff_filespec *dfs)
{
	int ret;
 
	ret = get_tree_entry(r, tree, path, &dfs->oid, &dfs->mode);
	if (S_ISDIR(dfs->mode)) {
		oidcpy(&dfs->oid, &null_oid);
		dfs->mode = 0;
	}
	return ret;
}
 
/*
 * Returns an index_entry instance which doesn't have to correspond to
 * a real cache entry in Git's index.
 */
static struct stage_data *insert_stage_data(struct repository *r,
		const char *path,
		struct tree *o, struct tree *a, struct tree *b,
		struct string_list *entries)
{
	struct string_list_item *item;
	struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
	get_tree_entry_if_blob(r, &o->object.oid, path, &e->stages[1]);
	get_tree_entry_if_blob(r, &a->object.oid, path, &e->stages[2]);
	get_tree_entry_if_blob(r, &b->object.oid, path, &e->stages[3]);
	item = string_list_insert(entries, path);
	item->util = e;
	return e;
}
 
/*
 * Create a dictionary mapping file names to stage_data objects. The
 * dictionary contains one entry for every path with a non-zero stage entry.
 */
static struct string_list *get_unmerged(struct index_state *istate)
{
	struct string_list *unmerged = xcalloc(1, sizeof(struct string_list));
	int i;
 
	unmerged->strdup_strings = 1;
 
	for (i = 0; i < istate->cache_nr; i++) {
		struct string_list_item *item;
		struct stage_data *e;
		const struct cache_entry *ce = istate->cache[i];
		if (!ce_stage(ce))
			continue;
 
		item = string_list_lookup(unmerged, ce->name);
		if (!item) {
			item = string_list_insert(unmerged, ce->name);
			item->util = xcalloc(1, sizeof(struct stage_data));
		}
		e = item->util;
		e->stages[ce_stage(ce)].mode = ce->ce_mode;
		oidcpy(&e->stages[ce_stage(ce)].oid, &ce->oid);
	}
 
	return unmerged;
}
 
static int string_list_df_name_compare(const char *one, const char *two)
{
	int onelen = strlen(one);
	int twolen = strlen(two);
	/*
	 * Here we only care that entries for D/F conflicts are
	 * adjacent, in particular with the file of the D/F conflict
	 * appearing before files below the corresponding directory.
	 * The order of the rest of the list is irrelevant for us.
	 *
	 * To achieve this, we sort with df_name_compare and provide
	 * the mode S_IFDIR so that D/F conflicts will sort correctly.
	 * We use the mode S_IFDIR for everything else for simplicity,
	 * since in other cases any changes in their order due to
	 * sorting cause no problems for us.
	 */
	int cmp = df_name_compare(one, onelen, S_IFDIR,
				  two, twolen, S_IFDIR);
	/*
	 * Now that 'foo' and 'foo/bar' compare equal, we have to make sure
	 * that 'foo' comes before 'foo/bar'.
	 */
	if (cmp)
		return cmp;
	return onelen - twolen;
}
 
static void record_df_conflict_files(struct merge_options *opt,
				     struct string_list *entries)
{
	/* If there is a D/F conflict and the file for such a conflict
	 * currently exists in the working tree, we want to allow it to be
	 * removed to make room for the corresponding directory if needed.
	 * The files underneath the directories of such D/F conflicts will
	 * be processed before the corresponding file involved in the D/F
	 * conflict.  If the D/F directory ends up being removed by the
	 * merge, then we won't have to touch the D/F file.  If the D/F
	 * directory needs to be written to the working copy, then the D/F
	 * file will simply be removed (in make_room_for_path()) to make
	 * room for the necessary paths.  Note that if both the directory
	 * and the file need to be present, then the D/F file will be
	 * reinstated with a new unique name at the time it is processed.
	 */
	struct string_list df_sorted_entries = STRING_LIST_INIT_NODUP;
	const char *last_file = NULL;
	int last_len = 0;
	int i;
 
	/*
	 * If we're merging merge-bases, we don't want to bother with
	 * any working directory changes.
	 */
	if (opt->priv->call_depth)
		return;
 
	/* Ensure D/F conflicts are adjacent in the entries list. */
	for (i = 0; i < entries->nr; i++) {
		struct string_list_item *next = &entries->items[i];
		string_list_append(&df_sorted_entries, next->string)->util =
				   next->util;
	}
	df_sorted_entries.cmp = string_list_df_name_compare;
	string_list_sort(&df_sorted_entries);
 
	string_list_clear(&opt->priv->df_conflict_file_set, 1);
	for (i = 0; i < df_sorted_entries.nr; i++) {
		const char *path = df_sorted_entries.items[i].string;
		int len = strlen(path);
		struct stage_data *e = df_sorted_entries.items[i].util;
 
		/*
		 * Check if last_file & path correspond to a D/F conflict;
		 * i.e. whether path is last_file+'/'+<something>.
		 * If so, record that it's okay to remove last_file to make
		 * room for path and friends if needed.
		 */
		if (last_file &&
		    len > last_len &&
		    memcmp(path, last_file, last_len) == 0 &&
		    path[last_len] == '/') {
			string_list_insert(&opt->priv->df_conflict_file_set, last_file);
		}
 
		/*
		 * Determine whether path could exist as a file in the
		 * working directory as a possible D/F conflict.  This
		 * will only occur when it exists in stage 2 as a
		 * file.
		 */
		if (S_ISREG(e->stages[2].mode) || S_ISLNK(e->stages[2].mode)) {
			last_file = path;
			last_len = len;
		} else {
			last_file = NULL;
		}
	}
	string_list_clear(&df_sorted_entries, 0);
}
 
static int update_stages(struct merge_options *opt, const char *path,
			 const struct diff_filespec *o,
			 const struct diff_filespec *a,
			 const struct diff_filespec *b)
{
 
	/*
	 * NOTE: It is usually a bad idea to call update_stages on a path
	 * before calling update_file on that same path, since it can
	 * sometimes lead to spurious "refusing to lose untracked file..."
	 * messages from update_file (via make_room_for path via
	 * would_lose_untracked).  Instead, reverse the order of the calls
	 * (executing update_file first and then update_stages).
	 */
	int clear = 1;
	int options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_SKIP_DFCHECK;
	if (clear)
		if (remove_file_from_index(opt->repo->index, path))
			return -1;
	if (o)
		if (add_cacheinfo(opt, o, path, 1, 0, options))
			return -1;
	if (a)
		if (add_cacheinfo(opt, a, path, 2, 0, options))
			return -1;
	if (b)
		if (add_cacheinfo(opt, b, path, 3, 0, options))
			return -1;
	return 0;
}
 
static void update_entry(struct stage_data *entry,
			 struct diff_filespec *o,
			 struct diff_filespec *a,
			 struct diff_filespec *b)
{
	entry->processed = 0;
	entry->stages[1].mode = o->mode;
	entry->stages[2].mode = a->mode;
	entry->stages[3].mode = b->mode;
	oidcpy(&entry->stages[1].oid, &o->oid);
	oidcpy(&entry->stages[2].oid, &a->oid);
	oidcpy(&entry->stages[3].oid, &b->oid);
}
 
static int remove_file(struct merge_options *opt, int clean,
		       const char *path, int no_wd)
{
	int update_cache = opt->priv->call_depth || clean;
	int update_working_directory = !opt->priv->call_depth && !no_wd;
 
	if (update_cache) {
		if (remove_file_from_index(opt->repo->index, path))
			return -1;
	}
	if (update_working_directory) {
		if (ignore_case) {
			struct cache_entry *ce;
			ce = index_file_exists(opt->repo->index, path, strlen(path),
					       ignore_case);
			if (ce && ce_stage(ce) == 0 && strcmp(path, ce->name))
				return 0;
		}
		if (remove_path(path))
			return -1;
	}
	return 0;
}
 
/* add a string to a strbuf, but converting "/" to "_" */
static void add_flattened_path(struct strbuf *out, const char *s)
{
	size_t i = out->len;
	strbuf_addstr(out, s);
	for (; i < out->len; i++)
		if (out->buf[i] == '/')
			out->buf[i] = '_';
}
 
static char *unique_path(struct merge_options *opt,
			 const char *path,
			 const char *branch)
{
	struct path_hashmap_entry *entry;
	struct strbuf newpath = STRBUF_INIT;
	int suffix = 0;
	size_t base_len;
 
	strbuf_addf(&newpath, "%s~", path);
	add_flattened_path(&newpath, branch);
 
	base_len = newpath.len;
	while (hashmap_get_from_hash(&opt->priv->current_file_dir_set,
				     path_hash(newpath.buf), newpath.buf) ||
	       (!opt->priv->call_depth && file_exists(newpath.buf))) {
		strbuf_setlen(&newpath, base_len);
		strbuf_addf(&newpath, "_%d", suffix++);
	}
 
	FLEX_ALLOC_MEM(entry, path, newpath.buf, newpath.len);
	hashmap_entry_init(&entry->e, path_hash(entry->path));
	hashmap_add(&opt->priv->current_file_dir_set, &entry->e);
	return strbuf_detach(&newpath, NULL);
}
 
/**
 * Check whether a directory in the index is in the way of an incoming
 * file.  Return 1 if so.  If check_working_copy is non-zero, also
 * check the working directory.  If empty_ok is non-zero, also return
 * 0 in the case where the working-tree dir exists but is empty.
 */
static int dir_in_way(struct index_state *istate, const char *path,
		      int check_working_copy, int empty_ok)
{
	int pos;
	struct strbuf dirpath = STRBUF_INIT;
	struct stat st;
 
	strbuf_addstr(&dirpath, path);
	strbuf_addch(&dirpath, '/');
 
	pos = index_name_pos(istate, dirpath.buf, dirpath.len);
 
	if (pos < 0)
		pos = -1 - pos;
	if (pos < istate->cache_nr &&
	    !strncmp(dirpath.buf, istate->cache[pos]->name, dirpath.len)) {
		strbuf_release(&dirpath);
		return 1;
	}
 
	strbuf_release(&dirpath);
	return check_working_copy && !lstat(path, &st) && S_ISDIR(st.st_mode) &&
		!(empty_ok && is_empty_dir(path)) &&
		!has_symlink_leading_path(path, strlen(path));
}
 
/*
 * Returns whether path was tracked in the index before the merge started,
 * and its oid and mode match the specified values
 */
static int was_tracked_and_matches(struct merge_options *opt, const char *path,
				   const struct diff_filespec *blob)
{
	int pos = index_name_pos(&opt->priv->orig_index, path, strlen(path));
	struct cache_entry *ce;
 
	if (0 > pos)
		/* we were not tracking this path before the merge */
		return 0;
 
	/* See if the file we were tracking before matches */
	ce = opt->priv->orig_index.cache[pos];
	return (oideq(&ce->oid, &blob->oid) && ce->ce_mode == blob->mode);
}
 
/*
 * Returns whether path was tracked in the index before the merge started
 */
static int was_tracked(struct merge_options *opt, const char *path)
{
	int pos = index_name_pos(&opt->priv->orig_index, path, strlen(path));
 
	if (0 <= pos)
		/* we were tracking this path before the merge */
		return 1;
 
	return 0;
}
 
static int would_lose_untracked(struct merge_options *opt, const char *path)
{
	struct index_state *istate = opt->repo->index;
 
	/*
	 * This may look like it can be simplified to:
	 *   return !was_tracked(opt, path) && file_exists(path)
	 * but it can't.  This function needs to know whether path was in
	 * the working tree due to EITHER having been tracked in the index
	 * before the merge OR having been put into the working copy and
	 * index by unpack_trees().  Due to that either-or requirement, we
	 * check the current index instead of the original one.
	 *
	 * Note that we do not need to worry about merge-recursive itself
	 * updating the index after unpack_trees() and before calling this
	 * function, because we strictly require all code paths in
	 * merge-recursive to update the working tree first and the index
	 * second.  Doing otherwise would break
	 * update_file()/would_lose_untracked(); see every comment in this
	 * file which mentions "update_stages".
	 */
	int pos = index_name_pos(istate, path, strlen(path));
 
	if (pos < 0)
		pos = -1 - pos;
	while (pos < istate->cache_nr &&
	       !strcmp(path, istate->cache[pos]->name)) {
		/*
		 * If stage #0, it is definitely tracked.
		 * If it has stage #2 then it was tracked
		 * before this merge started.  All other
		 * cases the path was not tracked.
		 */
		switch (ce_stage(istate->cache[pos])) {
		case 0:
		case 2:
			return 0;
		}
		pos++;
	}
	return file_exists(path);
}
 
static int was_dirty(struct merge_options *opt, const char *path)
{
	struct cache_entry *ce;
	int dirty = 1;
 
	if (opt->priv->call_depth || !was_tracked(opt, path))
		return !dirty;
 
	ce = index_file_exists(opt->priv->unpack_opts.src_index,
			       path, strlen(path), ignore_case);
	dirty = verify_uptodate(ce, &opt->priv->unpack_opts) != 0;
	return dirty;
}
 
static int make_room_for_path(struct merge_options *opt, const char *path)
{
	int status, i;
	const char *msg = _("failed to create path '%s'%s");
 
	/* Unlink any D/F conflict files that are in the way */
	for (i = 0; i < opt->priv->df_conflict_file_set.nr; i++) {
		const char *df_path = opt->priv->df_conflict_file_set.items[i].string;
		size_t pathlen = strlen(path);
		size_t df_pathlen = strlen(df_path);
		if (df_pathlen < pathlen &&
		    path[df_pathlen] == '/' &&
		    strncmp(path, df_path, df_pathlen) == 0) {
			output(opt, 3,
			       _("Removing %s to make room for subdirectory\n"),
			       df_path);
			unlink(df_path);
			unsorted_string_list_delete_item(&opt->priv->df_conflict_file_set,
							 i, 0);
			break;
		}
	}
 
	/* Make sure leading directories are created */
	status = safe_create_leading_directories_const(path);
	if (status) {
		if (status == SCLD_EXISTS)
			/* something else exists */
			return err(opt, msg, path, _(": perhaps a D/F conflict?"));
		return err(opt, msg, path, "");
	}
 
	/*
	 * Do not unlink a file in the work tree if we are not
	 * tracking it.
	 */
	if (would_lose_untracked(opt, path))
		return err(opt, _("refusing to lose untracked file at '%s'"),
			   path);
 
	/* Successful unlink is good.. */
	if (!unlink(path))
		return 0;
	/* .. and so is no existing file */
	if (errno == ENOENT)
		return 0;
	/* .. but not some other error (who really cares what?) */
	return err(opt, msg, path, _(": perhaps a D/F conflict?"));
}
 
static int update_file_flags(struct merge_options *opt,
			     const struct diff_filespec *contents,
			     const char *path,
			     int update_cache,
			     int update_wd)
{
	int ret = 0;
 
	if (opt->priv->call_depth)
		update_wd = 0;
 
	if (update_wd) {
		enum object_type type;
		void *buf;
		unsigned long size;
 
		if (S_ISGITLINK(contents->mode)) {
			/*
			 * We may later decide to recursively descend into
			 * the submodule directory and update its index
			 * and/or work tree, but we do not do that now.
			 */
			update_wd = 0;
			goto update_index;
		}
 
		buf = read_object_file(&contents->oid, &type, &size);
		if (!buf) {
			ret = err(opt, _("cannot read object %s '%s'"),
				  oid_to_hex(&contents->oid), path);
			goto free_buf;
		}
		if (type != OBJ_BLOB) {
			ret = err(opt, _("blob expected for %s '%s'"),
				  oid_to_hex(&contents->oid), path);
			goto free_buf;
		}
		if (S_ISREG(contents->mode)) {
			struct strbuf strbuf = STRBUF_INIT;
			if (convert_to_working_tree(opt->repo->index,
						    path, buf, size, &strbuf, NULL)) {
				free(buf);
				size = strbuf.len;
				buf = strbuf_detach(&strbuf, NULL);
			}
		}
 
		if (make_room_for_path(opt, path) < 0) {
			update_wd = 0;
			goto free_buf;
		}
		if (S_ISREG(contents->mode) ||
		    (!has_symlinks && S_ISLNK(contents->mode))) {
			int fd;
			int mode = (contents->mode & 0100 ? 0777 : 0666);
 
			fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
			if (fd < 0) {
				ret = err(opt, _("failed to open '%s': %s"),
					  path, strerror(errno));
				goto free_buf;
			}
			write_in_full(fd, buf, size);
			close(fd);
		} else if (S_ISLNK(contents->mode)) {
			char *lnk = xmemdupz(buf, size);
			safe_create_leading_directories_const(path);
			unlink(path);
			if (symlink(lnk, path))
				ret = err(opt, _("failed to symlink '%s': %s"),
					  path, strerror(errno));
			free(lnk);
		} else
			ret = err(opt,
				  _("do not know what to do with %06o %s '%s'"),
				  contents->mode, oid_to_hex(&contents->oid), path);
	free_buf:
		free(buf);
	}
update_index:
	if (!ret && update_cache) {
		int refresh = (!opt->priv->call_depth &&
			       contents->mode != S_IFGITLINK);
		if (add_cacheinfo(opt, contents, path, 0, refresh,
				  ADD_CACHE_OK_TO_ADD))
			return -1;
	}
	return ret;
}
 
static int update_file(struct merge_options *opt,
		       int clean,
		       const struct diff_filespec *contents,
		       const char *path)
{
	return update_file_flags(opt, contents, path,
				 opt->priv->call_depth || clean, !opt->priv->call_depth);
}
 
/* Low level file merging, update and removal */
 
struct merge_file_info {
	struct diff_filespec blob; /* mostly use oid & mode; sometimes path */
	unsigned clean:1,
		 merge:1;
};
 
static int merge_3way(struct merge_options *opt,
		      mmbuffer_t *result_buf,
		      const struct diff_filespec *o,
		      const struct diff_filespec *a,
		      const struct diff_filespec *b,
		      const char *branch1,
		      const char *branch2,
		      const int extra_marker_size)
{
	mmfile_t orig, src1, src2;
	struct ll_merge_options ll_opts = {0};
	char *base, *name1, *name2;
	int merge_status;
 
	ll_opts.renormalize = opt->renormalize;
	ll_opts.extra_marker_size = extra_marker_size;
	ll_opts.xdl_opts = opt->xdl_opts;
 
	if (opt->priv->call_depth) {
		ll_opts.virtual_ancestor = 1;
		ll_opts.variant = 0;
	} else {
		switch (opt->recursive_variant) {
		case MERGE_VARIANT_OURS:
			ll_opts.variant = XDL_MERGE_FAVOR_OURS;
			break;
		case MERGE_VARIANT_THEIRS:
			ll_opts.variant = XDL_MERGE_FAVOR_THEIRS;
			break;
		default:
			ll_opts.variant = 0;
			break;
		}
	}
 
	assert(a->path && b->path && o->path && opt->ancestor);
	if (strcmp(a->path, b->path) || strcmp(a->path, o->path) != 0) {
		base  = mkpathdup("%s:%s", opt->ancestor, o->path);
		name1 = mkpathdup("%s:%s", branch1, a->path);
		name2 = mkpathdup("%s:%s", branch2, b->path);
	} else {
		base  = mkpathdup("%s", opt->ancestor);
		name1 = mkpathdup("%s", branch1);
		name2 = mkpathdup("%s", branch2);
	}
 
	read_mmblob(&orig, &o->oid);
	read_mmblob(&src1, &a->oid);
	read_mmblob(&src2, &b->oid);
 
	merge_status = ll_merge(result_buf, a->path, &orig, base,
				&src1, name1, &src2, name2,
				opt->repo->index, &ll_opts);
 
	free(base);
	free(name1);
	free(name2);
	free(orig.ptr);
	free(src1.ptr);
	free(src2.ptr);
	return merge_status;
}
 
static int find_first_merges(struct repository *repo,
			     struct object_array *result, const char *path,
			     struct commit *a, struct commit *b)
{
	int i, j;
	struct object_array merges = OBJECT_ARRAY_INIT;
	struct commit *commit;
	int contains_another;
 
	char merged_revision[GIT_MAX_HEXSZ + 2];
	const char *rev_args[] = { "rev-list", "--merges", "--ancestry-path",
				   "--all", merged_revision, NULL };
	struct rev_info revs;
	struct setup_revision_opt rev_opts;
 
	memset(result, 0, sizeof(struct object_array));
	memset(&rev_opts, 0, sizeof(rev_opts));
 
	/* get all revisions that merge commit a */
	xsnprintf(merged_revision, sizeof(merged_revision), "^%s",
		  oid_to_hex(&a->object.oid));
	repo_init_revisions(repo, &revs, NULL);
	rev_opts.submodule = path;
	/* FIXME: can't handle linked worktrees in submodules yet */
	revs.single_worktree = path != NULL;
	setup_revisions(ARRAY_SIZE(rev_args)-1, rev_args, &revs, &rev_opts);
 
	/* save all revisions from the above list that contain b */
	if (prepare_revision_walk(&revs))
		die("revision walk setup failed");
	while ((commit = get_revision(&revs)) != NULL) {
		struct object *o = &(commit->object);
		if (in_merge_bases(b, commit))
			add_object_array(o, NULL, &merges);
	}
	reset_revision_walk();
 
	/* Now we've got all merges that contain a and b. Prune all
	 * merges that contain another found merge and save them in
	 * result.
	 */
	for (i = 0; i < merges.nr; i++) {
		struct commit *m1 = (struct commit *) merges.objects[i].item;
 
		contains_another = 0;
		for (j = 0; j < merges.nr; j++) {
			struct commit *m2 = (struct commit *) merges.objects[j].item;
			if (i != j && in_merge_bases(m2, m1)) {
				contains_another = 1;
				break;
			}
		}
 
		if (!contains_another)
			add_object_array(merges.objects[i].item, NULL, result);
	}
 
	object_array_clear(&merges);
	return result->nr;
}
 
static void print_commit(struct commit *commit)
{
	struct strbuf sb = STRBUF_INIT;
	struct pretty_print_context ctx = {0};
	ctx.date_mode.type = DATE_NORMAL;
	format_commit_message(commit, " %h: %m %s", &sb, &ctx);
	fprintf(stderr, "%s\n", sb.buf);
	strbuf_release(&sb);
}
 
static int is_valid(const struct diff_filespec *dfs)
{
	return dfs->mode != 0 && !is_null_oid(&dfs->oid);
}
 
static int merge_submodule(struct merge_options *opt,
			   struct object_id *result, const char *path,
			   const struct object_id *base, const struct object_id *a,
			   const struct object_id *b)
{
	struct commit *commit_base, *commit_a, *commit_b;
	int parent_count;
	struct object_array merges;
 
	int i;
	int search = !opt->priv->call_depth;
 
	/* store a in result in case we fail */
	oidcpy(result, a);
 
	/* we can not handle deletion conflicts */
	if (is_null_oid(base))
		return 0;
	if (is_null_oid(a))
		return 0;
	if (is_null_oid(b))
		return 0;
 
	if (add_submodule_odb(path)) {
		output(opt, 1, _("Failed to merge submodule %s (not checked out)"), path);
		return 0;
	}
 
	if (!(commit_base = lookup_commit_reference(opt->repo, base)) ||
	    !(commit_a = lookup_commit_reference(opt->repo, a)) ||
	    !(commit_b = lookup_commit_reference(opt->repo, b))) {
		output(opt, 1, _("Failed to merge submodule %s (commits not present)"), path);
		return 0;
	}
 
	/* check whether both changes are forward */
	if (!in_merge_bases(commit_base, commit_a) ||
	    !in_merge_bases(commit_base, commit_b)) {
		output(opt, 1, _("Failed to merge submodule %s (commits don't follow merge-base)"), path);
		return 0;
	}
 
	/* Case #1: a is contained in b or vice versa */
	if (in_merge_bases(commit_a, commit_b)) {
		oidcpy(result, b);
		if (show(opt, 3)) {
			output(opt, 3, _("Fast-forwarding submodule %s to the following commit:"), path);
			output_commit_title(opt, commit_b);
		} else if (show(opt, 2))
			output(opt, 2, _("Fast-forwarding submodule %s"), path);
		else
			; /* no output */
 
		return 1;
	}
	if (in_merge_bases(commit_b, commit_a)) {
		oidcpy(result, a);
		if (show(opt, 3)) {
			output(opt, 3, _("Fast-forwarding submodule %s to the following commit:"), path);
			output_commit_title(opt, commit_a);
		} else if (show(opt, 2))
			output(opt, 2, _("Fast-forwarding submodule %s"), path);
		else
			; /* no output */
 
		return 1;
	}
 
	/*
	 * Case #2: There are one or more merges that contain a and b in
	 * the submodule. If there is only one, then present it as a
	 * suggestion to the user, but leave it marked unmerged so the
	 * user needs to confirm the resolution.
	 */
 
	/* Skip the search if makes no sense to the calling context.  */
	if (!search)
		return 0;
 
	/* find commit which merges them */
	parent_count = find_first_merges(opt->repo, &merges, path,
					 commit_a, commit_b);
	switch (parent_count) {
	case 0:
		output(opt, 1, _("Failed to merge submodule %s (merge following commits not found)"), path);
		break;
 
	case 1:
		output(opt, 1, _("Failed to merge submodule %s (not fast-forward)"), path);
		output(opt, 2, _("Found a possible merge resolution for the submodule:\n"));
		print_commit((struct commit *) merges.objects[0].item);
		output(opt, 2, _(
		       "If this is correct simply add it to the index "
		       "for example\n"
		       "by using:\n\n"
		       "  git update-index --cacheinfo 160000 %s \"%s\"\n\n"
		       "which will accept this suggestion.\n"),
		       oid_to_hex(&merges.objects[0].item->oid), path);
		break;
 
	default:
		output(opt, 1, _("Failed to merge submodule %s (multiple merges found)"), path);
		for (i = 0; i < merges.nr; i++)
			print_commit((struct commit *) merges.objects[i].item);
	}
 
	object_array_clear(&merges);
	return 0;
}
 
static int merge_mode_and_contents(struct merge_options *opt,
				   const struct diff_filespec *o,
				   const struct diff_filespec *a,
				   const struct diff_filespec *b,
				   const char *filename,
				   const char *branch1,
				   const char *branch2,
				   const int extra_marker_size,
				   struct merge_file_info *result)
{
	if (opt->branch1 != branch1) {
		/*
		 * It's weird getting a reverse merge with HEAD on the bottom
		 * side of the conflict markers and the other branch on the
		 * top.  Fix that.
		 */
		return merge_mode_and_contents(opt, o, b, a,
					       filename,
					       branch2, branch1,
					       extra_marker_size, result);
	}
 
	result->merge = 0;
	result->clean = 1;
 
	if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
		result->clean = 0;
		if (S_ISREG(a->mode)) {
			result->blob.mode = a->mode;
			oidcpy(&result->blob.oid, &a->oid);
		} else {
			result->blob.mode = b->mode;
			oidcpy(&result->blob.oid, &b->oid);
		}
	} else {
		if (!oideq(&a->oid, &o->oid) && !oideq(&b->oid, &o->oid))
			result->merge = 1;
 
		/*
		 * Merge modes
		 */
		if (a->mode == b->mode || a->mode == o->mode)
			result->blob.mode = b->mode;
		else {
			result->blob.mode = a->mode;
			if (b->mode != o->mode) {
				result->clean = 0;
				result->merge = 1;
			}
		}
 
		if (oideq(&a->oid, &b->oid) || oideq(&a->oid, &o->oid))
			oidcpy(&result->blob.oid, &b->oid);
		else if (oideq(&b->oid, &o->oid))
			oidcpy(&result->blob.oid, &a->oid);
		else if (S_ISREG(a->mode)) {
			mmbuffer_t result_buf;
			int ret = 0, merge_status;
 
			merge_status = merge_3way(opt, &result_buf, o, a, b,
						  branch1, branch2,
						  extra_marker_size);
 
			if ((merge_status < 0) || !result_buf.ptr)
				ret = err(opt, _("Failed to execute internal merge"));
 
			if (!ret &&
			    write_object_file(result_buf.ptr, result_buf.size,
					      blob_type, &result->blob.oid))
				ret = err(opt, _("Unable to add %s to database"),
					  a->path);
 
			free(result_buf.ptr);
			if (ret)
				return ret;
			result->clean = (merge_status == 0);
		} else if (S_ISGITLINK(a->mode)) {
			result->clean = merge_submodule(opt, &result->blob.oid,
							o->path,
							&o->oid,
							&a->oid,
							&b->oid);
		} else if (S_ISLNK(a->mode)) {
			switch (opt->recursive_variant) {
			case MERGE_VARIANT_NORMAL:
				oidcpy(&result->blob.oid, &a->oid);
				if (!oideq(&a->oid, &b->oid))
					result->clean = 0;
				break;
			case MERGE_VARIANT_OURS:
				oidcpy(&result->blob.oid, &a->oid);
				break;
			case MERGE_VARIANT_THEIRS:
				oidcpy(&result->blob.oid, &b->oid);
				break;
			}
		} else
			BUG("unsupported object type in the tree");
	}
 
	if (result->merge)
		output(opt, 2, _("Auto-merging %s"), filename);
 
	return 0;
}
 
static int handle_rename_via_dir(struct merge_options *opt,
				 struct rename_conflict_info *ci)
{
	/*
	 * Handle file adds that need to be renamed due to directory rename
	 * detection.  This differs from handle_rename_normal, because
	 * there is no content merge to do; just move the file into the
	 * desired final location.
	 */
	const struct rename *ren = ci->ren1;
	const struct diff_filespec *dest = ren->pair->two;
	char *file_path = dest->path;
	int mark_conflicted = (opt->detect_directory_renames ==
			       MERGE_DIRECTORY_RENAMES_CONFLICT);
	assert(ren->dir_rename_original_dest);
 
	if (!opt->priv->call_depth && would_lose_untracked(opt, dest->path)) {
		mark_conflicted = 1;
		file_path = unique_path(opt, dest->path, ren->branch);
		output(opt, 1, _("Error: Refusing to lose untracked file at %s; "
				 "writing to %s instead."),
		       dest->path, file_path);
	}
 
	if (mark_conflicted) {
		/*
		 * Write the file in worktree at file_path.  In the index,
		 * only record the file at dest->path in the appropriate
		 * higher stage.
		 */
		if (update_file(opt, 0, dest, file_path))
			return -1;
		if (file_path != dest->path)
			free(file_path);
		if (update_stages(opt, dest->path, NULL,
				  ren->branch == opt->branch1 ? dest : NULL,
				  ren->branch == opt->branch1 ? NULL : dest))
			return -1;
		return 0; /* not clean, but conflicted */
	} else {
		/* Update dest->path both in index and in worktree */
		if (update_file(opt, 1, dest, dest->path))
			return -1;
		return 1; /* clean */
	}
}
 
static int handle_change_delete(struct merge_options *opt,
				const char *path, const char *old_path,
				const struct diff_filespec *o,
				const struct diff_filespec *changed,
				const char *change_branch,
				const char *delete_branch,
				const char *change, const char *change_past)
{
	char *alt_path = NULL;
	const char *update_path = path;
	int ret = 0;
 
	if (dir_in_way(opt->repo->index, path, !opt->priv->call_depth, 0) ||
	    (!opt->priv->call_depth && would_lose_untracked(opt, path))) {
		update_path = alt_path = unique_path(opt, path, change_branch);
	}
 
	if (opt->priv->call_depth) {
		/*
		 * We cannot arbitrarily accept either a_sha or b_sha as
		 * correct; since there is no true "middle point" between
		 * them, simply reuse the base version for virtual merge base.
		 */
		ret = remove_file_from_index(opt->repo->index, path);
		if (!ret)
			ret = update_file(opt, 0, o, update_path);
	} else {
		/*
		 * Despite the four nearly duplicate messages and argument
		 * lists below and the ugliness of the nested if-statements,
		 * having complete messages makes the job easier for
		 * translators.
		 *
		 * The slight variance among the cases is due to the fact
		 * that:
		 *   1) directory/file conflicts (in effect if
		 *      !alt_path) could cause us to need to write the
		 *      file to a different path.
		 *   2) renames (in effect if !old_path) could mean that
		 *      there are two names for the path that the user
		 *      may know the file by.
		 */
		if (!alt_path) {
			if (!old_path) {
				output(opt, 1, _("CONFLICT (%s/delete): %s deleted in %s "
				       "and %s in %s. Version %s of %s left in tree."),
				       change, path, delete_branch, change_past,
				       change_branch, change_branch, path);
			} else {
				output(opt, 1, _("CONFLICT (%s/delete): %s deleted in %s "
				       "and %s to %s in %s. Version %s of %s left in tree."),
				       change, old_path, delete_branch, change_past, path,
				       change_branch, change_branch, path);
			}
		} else {
			if (!old_path) {
				output(opt, 1, _("CONFLICT (%s/delete): %s deleted in %s "
				       "and %s in %s. Version %s of %s left in tree at %s."),
				       change, path, delete_branch, change_past,
				       change_branch, change_branch, path, alt_path);
			} else {
				output(opt, 1, _("CONFLICT (%s/delete): %s deleted in %s "
				       "and %s to %s in %s. Version %s of %s left in tree at %s."),
				       change, old_path, delete_branch, change_past, path,
				       change_branch, change_branch, path, alt_path);
			}
		}
		/*
		 * No need to call update_file() on path when change_branch ==
		 * opt->branch1 && !alt_path, since that would needlessly touch
		 * path.  We could call update_file_flags() with update_cache=0
		 * and update_wd=0, but that's a no-op.
		 */
		if (change_branch != opt->branch1 || alt_path)
			ret = update_file(opt, 0, changed, update_path);
	}
	free(alt_path);
 
	return ret;
}
 
static int handle_rename_delete(struct merge_options *opt,
				struct rename_conflict_info *ci)
{
	const struct rename *ren = ci->ren1;
	const struct diff_filespec *orig = ren->pair->one;
	const struct diff_filespec *dest = ren->pair->two;
	const char *rename_branch = ren->branch;
	const char *delete_branch = (opt->branch1 == ren->branch ?
				     opt->branch2 : opt->branch1);
 
	if (handle_change_delete(opt,
				 opt->priv->call_depth ? orig->path : dest->path,
				 opt->priv->call_depth ? NULL : orig->path,
				 orig, dest,
				 rename_branch, delete_branch,
				 _("rename"), _("renamed")))
		return -1;
 
	if (opt->priv->call_depth)
		return remove_file_from_index(opt->repo->index, dest->path);
	else
		return update_stages(opt, dest->path, NULL,
				     rename_branch == opt->branch1 ? dest : NULL,
				     rename_branch == opt->branch1 ? NULL : dest);
}
 
static int handle_file_collision(struct merge_options *opt,
				 const char *collide_path,
				 const char *prev_path1,
				 const char *prev_path2,
				 const char *branch1, const char *branch2,
				 struct diff_filespec *a,
				 struct diff_filespec *b)
{
	struct merge_file_info mfi;
	struct diff_filespec null;
	char *alt_path = NULL;
	const char *update_path = collide_path;
 
	/*
	 * It's easiest to get the correct things into stage 2 and 3, and
	 * to make sure that the content merge puts HEAD before the other
	 * branch if we just ensure that branch1 == opt->branch1.  So, simply
	 * flip arguments around if we don't have that.
	 */
	if (branch1 != opt->branch1) {
		return handle_file_collision(opt, collide_path,
					     prev_path2, prev_path1,
					     branch2, branch1,
					     b, a);
	}
 
	/* Remove rename sources if rename/add or rename/rename(2to1) */
	if (prev_path1)
		remove_file(opt, 1, prev_path1,
			    opt->priv->call_depth || would_lose_untracked(opt, prev_path1));
	if (prev_path2)
		remove_file(opt, 1, prev_path2,
			    opt->priv->call_depth || would_lose_untracked(opt, prev_path2));
 
	/*
	 * Remove the collision path, if it wouldn't cause dirty contents
	 * or an untracked file to get lost.  We'll either overwrite with
	 * merged contents, or just write out to differently named files.
	 */
	if (was_dirty(opt, collide_path)) {
		output(opt, 1, _("Refusing to lose dirty file at %s"),
		       collide_path);
		update_path = alt_path = unique_path(opt, collide_path, "merged");
	} else if (would_lose_untracked(opt, collide_path)) {
		/*
		 * Only way we get here is if both renames were from
		 * a directory rename AND user had an untracked file
		 * at the location where both files end up after the
		 * two directory renames.  See testcase 10d of t6043.
		 */
		output(opt, 1, _("Refusing to lose untracked file at "
			       "%s, even though it's in the way."),
		       collide_path);
		update_path = alt_path = unique_path(opt, collide_path, "merged");
	} else {
		/*
		 * FIXME: It's possible that the two files are identical
		 * and that the current working copy happens to match, in
		 * which case we are unnecessarily touching the working
		 * tree file.  It's not a likely enough scenario that I
		 * want to code up the checks for it and a better fix is
		 * available if we restructure how unpack_trees() and
		 * merge-recursive interoperate anyway, so punting for
		 * now...
		 */
		remove_file(opt, 0, collide_path, 0);
	}
 
	/* Store things in diff_filespecs for functions that need it */
	null.path = (char *)collide_path;
	oidcpy(&null.oid, &null_oid);
	null.mode = 0;
 
	if (merge_mode_and_contents(opt, &null, a, b, collide_path,
				    branch1, branch2, opt->priv->call_depth * 2, &mfi))
		return -1;
	mfi.clean &= !alt_path;
	if (update_file(opt, mfi.clean, &mfi.blob, update_path))
		return -1;
	if (!mfi.clean && !opt->priv->call_depth &&
	    update_stages(opt, collide_path, NULL, a, b))
		return -1;
	free(alt_path);
	/*
	 * FIXME: If both a & b both started with conflicts (only possible
	 * if they came from a rename/rename(2to1)), but had IDENTICAL
	 * contents including those conflicts, then in the next line we claim
	 * it was clean.  If someone cares about this case, we should have the
	 * caller notify us if we started with conflicts.
	 */
	return mfi.clean;
}
 
static int handle_rename_add(struct merge_options *opt,
			     struct rename_conflict_info *ci)
{
	/* a was renamed to c, and a separate c was added. */
	struct diff_filespec *a = ci->ren1->pair->one;
	struct diff_filespec *c = ci->ren1->pair->two;
	char *path = c->path;
	char *prev_path_desc;
	struct merge_file_info mfi;
 
	const char *rename_branch = ci->ren1->branch;
	const char *add_branch = (opt->branch1 == rename_branch ?
				  opt->branch2 : opt->branch1);
	int other_stage = (ci->ren1->branch == opt->branch1 ? 3 : 2);
 
	output(opt, 1, _("CONFLICT (rename/add): "
	       "Rename %s->%s in %s.  Added %s in %s"),
	       a->path, c->path, rename_branch,
	       c->path, add_branch);
 
	prev_path_desc = xstrfmt("version of %s from %s", path, a->path);
	ci->ren1->src_entry->stages[other_stage].path = a->path;
	if (merge_mode_and_contents(opt, a, c,
				    &ci->ren1->src_entry->stages[other_stage],
				    prev_path_desc,
				    opt->branch1, opt->branch2,
				    1 + opt->priv->call_depth * 2, &mfi))
		return -1;
	free(prev_path_desc);
 
	ci->ren1->dst_entry->stages[other_stage].path = mfi.blob.path = c->path;
	return handle_file_collision(opt,
				     c->path, a->path, NULL,
				     rename_branch, add_branch,
				     &mfi.blob,
				     &ci->ren1->dst_entry->stages[other_stage]);
}
 
static char *find_path_for_conflict(struct merge_options *opt,
				    const char *path,
				    const char *branch1,
				    const char *branch2)
{
	char *new_path = NULL;
	if (dir_in_way(opt->repo->index, path, !opt->priv->call_depth, 0)) {
		new_path = unique_path(opt, path, branch1);
		output(opt, 1, _("%s is a directory in %s adding "
			       "as %s instead"),
		       path, branch2, new_path);
	} else if (would_lose_untracked(opt, path)) {
		new_path = unique_path(opt, path, branch1);
		output(opt, 1, _("Refusing to lose untracked file"
			       " at %s; adding as %s instead"),
		       path, new_path);
	}
 
	return new_path;
}
 
/*
 * Toggle the stage number between "ours" and "theirs" (2 and 3).
 */
static inline int flip_stage(int stage)
{
	return (2 + 3) - stage;
}
 
static int handle_rename_rename_1to2(struct merge_options *opt,
				     struct rename_conflict_info *ci)
{
	/* One file was renamed in both branches, but to different names. */
	struct merge_file_info mfi;
	struct diff_filespec *add;
	struct diff_filespec *o = ci->ren1->pair->one;
	struct diff_filespec *a = ci->ren1->pair->two;
	struct diff_filespec *b = ci->ren2->pair->two;
	char *path_desc;
 
	output(opt, 1, _("CONFLICT (rename/rename): "
	       "Rename \"%s\"->\"%s\" in branch \"%s\" "
	       "rename \"%s\"->\"%s\" in \"%s\"%s"),
	       o->path, a->path, ci->ren1->branch,
	       o->path, b->path, ci->ren2->branch,
	       opt->priv->call_depth ? _(" (left unresolved)") : "");
 
	path_desc = xstrfmt("%s and %s, both renamed from %s",
			    a->path, b->path, o->path);
	if (merge_mode_and_contents(opt, o, a, b, path_desc,
				    ci->ren1->branch, ci->ren2->branch,
				    opt->priv->call_depth * 2, &mfi))
		return -1;
	free(path_desc);
 
	if (opt->priv->call_depth)
		remove_file_from_index(opt->repo->index, o->path);
 
	/*
	 * For each destination path, we need to see if there is a
	 * rename/add collision.  If not, we can write the file out
	 * to the specified location.
	 */
	add = &ci->ren1->dst_entry->stages[flip_stage(2)];
	if (is_valid(add)) {
		add->path = mfi.blob.path = a->path;
		if (handle_file_collision(opt, a->path,
					  NULL, NULL,
					  ci->ren1->branch,
					  ci->ren2->branch,
					  &mfi.blob, add) < 0)
			return -1;
	} else {
		char *new_path = find_path_for_conflict(opt, a->path,
							ci->ren1->branch,
							ci->ren2->branch);
		if (update_file(opt, 0, &mfi.blob,
				new_path ? new_path : a->path))
			return -1;
		free(new_path);
		if (!opt->priv->call_depth &&
		    update_stages(opt, a->path, NULL, a, NULL))
			return -1;
	}
 
	if (!mfi.clean && mfi.blob.mode == a->mode &&
	    oideq(&mfi.blob.oid, &a->oid)) {
		/*
		 * Getting here means we were attempting to merge a binary
		 * blob.  Since we can't merge binaries, the merge algorithm
		 * just takes one side.  But we don't want to copy the
		 * contents of one side to both paths; we'd rather use the
		 * original content at the given path for each path.
		 */
		oidcpy(&mfi.blob.oid, &b->oid);
		mfi.blob.mode = b->mode;
	}
	add = &ci->ren2->dst_entry->stages[flip_stage(3)];
	if (is_valid(add)) {
		add->path = mfi.blob.path = b->path;
		if (handle_file_collision(opt, b->path,
					  NULL, NULL,
					  ci->ren1->branch,
					  ci->ren2->branch,
					  add, &mfi.blob) < 0)
			return -1;
	} else {
		char *new_path = find_path_for_conflict(opt, b->path,
							ci->ren2->branch,
							ci->ren1->branch);
		if (update_file(opt, 0, &mfi.blob,
				new_path ? new_path : b->path))
			return -1;
		free(new_path);
		if (!opt->priv->call_depth &&
		    update_stages(opt, b->path, NULL, NULL, b))
			return -1;
	}
 
	return 0;
}
 
static int handle_rename_rename_2to1(struct merge_options *opt,
				     struct rename_conflict_info *ci)
{
	/* Two files, a & b, were renamed to the same thing, c. */
	struct diff_filespec *a = ci->ren1->pair->one;
	struct diff_filespec *b = ci->ren2->pair->one;
	struct diff_filespec *c1 = ci->ren1->pair->two;
	struct diff_filespec *c2 = ci->ren2->pair->two;
	char *path = c1->path; /* == c2->path */
	char *path_side_1_desc;
	char *path_side_2_desc;
	struct merge_file_info mfi_c1;
	struct merge_file_info mfi_c2;
	int ostage1, ostage2;
 
	output(opt, 1, _("CONFLICT (rename/rename): "
	       "Rename %s->%s in %s. "
	       "Rename %s->%s in %s"),
	       a->path, c1->path, ci->ren1->branch,
	       b->path, c2->path, ci->ren2->branch);
 
	path_side_1_desc = xstrfmt("version of %s from %s", path, a->path);
	path_side_2_desc = xstrfmt("version of %s from %s", path, b->path);
	ostage1 = ci->ren1->branch == opt->branch1 ? 3 : 2;
	ostage2 = flip_stage(ostage1);
	ci->ren1->src_entry->stages[ostage1].path = a->path;
	ci->ren2->src_entry->stages[ostage2].path = b->path;
	if (merge_mode_and_contents(opt, a, c1,
				    &ci->ren1->src_entry->stages[ostage1],
				    path_side_1_desc,
				    opt->branch1, opt->branch2,
				    1 + opt->priv->call_depth * 2, &mfi_c1) ||
	    merge_mode_and_contents(opt, b,
				    &ci->ren2->src_entry->stages[ostage2],
				    c2, path_side_2_desc,
				    opt->branch1, opt->branch2,
				    1 + opt->priv->call_depth * 2, &mfi_c2))
		return -1;
	free(path_side_1_desc);
	free(path_side_2_desc);
	mfi_c1.blob.path = path;
	mfi_c2.blob.path = path;
 
	return handle_file_collision(opt, path, a->path, b->path,
				     ci->ren1->branch, ci->ren2->branch,
				     &mfi_c1.blob, &mfi_c2.blob);
}
 
/*
 * Get the diff_filepairs changed between o_tree and tree.
 */
static struct diff_queue_struct *get_diffpairs(struct merge_options *opt,
					       struct tree *o_tree,
					       struct tree *tree)
{
	struct diff_queue_struct *ret;
	struct diff_options opts;
 
	repo_diff_setup(opt->repo, &opts);
	opts.flags.recursive = 1;
	opts.flags.rename_empty = 0;
	opts.detect_rename = merge_detect_rename(opt);
	/*
	 * We do not have logic to handle the detection of copies.  In
	 * fact, it may not even make sense to add such logic: would we
	 * really want a change to a base file to be propagated through
	 * multiple other files by a merge?
	 */
	if (opts.detect_rename > DIFF_DETECT_RENAME)
		opts.detect_rename = DIFF_DETECT_RENAME;
	opts.rename_limit = (opt->rename_limit >= 0) ? opt->rename_limit : 1000;
	opts.rename_score = opt->rename_score;
	opts.show_rename_progress = opt->show_rename_progress;
	opts.output_format = DIFF_FORMAT_NO_OUTPUT;
	diff_setup_done(&opts);
	diff_tree_oid(&o_tree->object.oid, &tree->object.oid, "", &opts);
	diffcore_std(&opts);
	if (opts.needed_rename_limit > opt->priv->needed_rename_limit)
		opt->priv->needed_rename_limit = opts.needed_rename_limit;
 
	ret = xmalloc(sizeof(*ret));
	*ret = diff_queued_diff;
 
	opts.output_format = DIFF_FORMAT_NO_OUTPUT;
	diff_queued_diff.nr = 0;
	diff_queued_diff.queue = NULL;
	diff_flush(&opts);
	return ret;
}
 
static int tree_has_path(struct repository *r, struct tree *tree,
			 const char *path)
{
	struct object_id hashy;
	unsigned short mode_o;
 
	return !get_tree_entry(r,
			       &tree->object.oid, path,
			       &hashy, &mode_o);
}
 
/*
 * Return a new string that replaces the beginning portion (which matches
 * entry->dir), with entry->new_dir.  In perl-speak:
 *   new_path_name = (old_path =~ s/entry->dir/entry->new_dir/);
 * NOTE:
 *   Caller must ensure that old_path starts with entry->dir + '/'.
 */
static char *apply_dir_rename(struct dir_rename_entry *entry,
			      const char *old_path)
{
	struct strbuf new_path = STRBUF_INIT;
	int oldlen, newlen;
 
	if (entry->non_unique_new_dir)
		return NULL;
 
	oldlen = strlen(entry->dir);
	if (entry->new_dir.len == 0)
		/*
		 * If someone renamed/merged a subdirectory into the root
		 * directory (e.g. 'some/subdir' -> ''), then we want to
		 * avoid returning
		 *     '' + '/filename'
		 * as the rename; we need to make old_path + oldlen advance
		 * past the '/' character.
		 */
		oldlen++;
	newlen = entry->new_dir.len + (strlen(old_path) - oldlen) + 1;
	strbuf_grow(&new_path, newlen);
	strbuf_addbuf(&new_path, &entry->new_dir);
	strbuf_addstr(&new_path, &old_path[oldlen]);
 
	return strbuf_detach(&new_path, NULL);
}
 
static void get_renamed_dir_portion(const char *old_path, const char *new_path,
				    char **old_dir, char **new_dir)
{
	char *end_of_old, *end_of_new;
 
	/* Default return values: NULL, meaning no rename */
	*old_dir = NULL;
	*new_dir = NULL;
 
	/*
	 * For
	 *    "a/b/c/d/e/foo.c" -> "a/b/some/thing/else/e/foo.c"
	 * the "e/foo.c" part is the same, we just want to know that
	 *    "a/b/c/d" was renamed to "a/b/some/thing/else"
	 * so, for this example, this function returns "a/b/c/d" in
	 * *old_dir and "a/b/some/thing/else" in *new_dir.
	 */
 
	/*
	 * If the basename of the file changed, we don't care.  We want
	 * to know which portion of the directory, if any, changed.
	 */
	end_of_old = strrchr(old_path, '/');
	end_of_new = strrchr(new_path, '/');
 
	/*
	 * If end_of_old is NULL, old_path wasn't in a directory, so there
	 * could not be a directory rename (our rule elsewhere that a
	 * directory which still exists is not considered to have been
	 * renamed means the root directory can never be renamed -- because
	 * the root directory always exists).
	 */
	if (end_of_old == NULL)
		return; /* Note: *old_dir and *new_dir are still NULL */
 
	/*
	 * If new_path contains no directory (end_of_new is NULL), then we
	 * have a rename of old_path's directory to the root directory.
	 */
	if (end_of_new == NULL) {
		*old_dir = xstrndup(old_path, end_of_old - old_path);
		*new_dir = xstrdup("");
		return;
	}
 
	/* Find the first non-matching character traversing backwards */
	while (*--end_of_new == *--end_of_old &&
	       end_of_old != old_path &&
	       end_of_new != new_path)
		; /* Do nothing; all in the while loop */
 
	/*
	 * If both got back to the beginning of their strings, then the
	 * directory didn't change at all, only the basename did.
	 */
	if (end_of_old == old_path && end_of_new == new_path &&
	    *end_of_old == *end_of_new)
		return; /* Note: *old_dir and *new_dir are still NULL */
 
	/*
	 * If end_of_new got back to the beginning of its string, and
	 * end_of_old got back to the beginning of some subdirectory, then
	 * we have a rename/merge of a subdirectory into the root, which
	 * needs slightly special handling.
	 *
	 * Note: There is no need to consider the opposite case, with a
	 * rename/merge of the root directory into some subdirectory
	 * because as noted above the root directory always exists so it
	 * cannot be considered to be renamed.
	 */
	if (end_of_new == new_path &&
	    end_of_old != old_path && end_of_old[-1] == '/') {
		*old_dir = xstrndup(old_path, --end_of_old - old_path);
		*new_dir = xstrdup("");
		return;
	}
 
	/*
	 * We've found the first non-matching character in the directory
	 * paths.  That means the current characters we were looking at
	 * were part of the first non-matching subdir name going back from
	 * the end of the strings.  Get the whole name by advancing both
	 * end_of_old and end_of_new to the NEXT '/' character.  That will
	 * represent the entire directory rename.
	 *
	 * The reason for the increment is cases like
	 *    a/b/star/foo/whatever.c -> a/b/tar/foo/random.c
	 * After dropping the basename and going back to the first
	 * non-matching character, we're now comparing:
	 *    a/b/s          and         a/b/
	 * and we want to be comparing:
	 *    a/b/star/      and         a/b/tar/
	 * but without the pre-increment, the one on the right would stay
	 * a/b/.
	 */
	end_of_old = strchr(++end_of_old, '/');
	end_of_new = strchr(++end_of_new, '/');
 
	/* Copy the old and new directories into *old_dir and *new_dir. */
	*old_dir = xstrndup(old_path, end_of_old - old_path);
	*new_dir = xstrndup(new_path, end_of_new - new_path);
}
 
static void remove_hashmap_entries(struct hashmap *dir_renames,
				   struct string_list *items_to_remove)
{
	int i;
	struct dir_rename_entry *entry;
 
	for (i = 0; i < items_to_remove->nr; i++) {
		entry = items_to_remove->items[i].util;
		hashmap_remove(dir_renames, &entry->ent, NULL);
	}
	string_list_clear(items_to_remove, 0);
}
 
/*
 * See if there is a directory rename for path, and if there are any file
 * level conflicts for the renamed location.  If there is a rename and
 * there are no conflicts, return the new name.  Otherwise, return NULL.
 */
static char *handle_path_level_conflicts(struct merge_options *opt,
					 const char *path,
					 struct dir_rename_entry *entry,
					 struct hashmap *collisions,
					 struct tree *tree)
{
	char *new_path = NULL;
	struct collision_entry *collision_ent;
	int clean = 1;
	struct strbuf collision_paths = STRBUF_INIT;
 
	/*
	 * entry has the mapping of old directory name to new directory name
	 * that we want to apply to path.
	 */
	new_path = apply_dir_rename(entry, path);
 
	if (!new_path) {
		/* This should only happen when entry->non_unique_new_dir set */
		if (!entry->non_unique_new_dir)
			BUG("entry->non_unqiue_dir not set and !new_path");
		output(opt, 1, _("CONFLICT (directory rename split): "
			       "Unclear where to place %s because directory "
			       "%s was renamed to multiple other directories, "
			       "with no destination getting a majority of the "
			       "files."),
		       path, entry->dir);
		clean = 0;
		return NULL;
	}
 
	/*
	 * The caller needs to have ensured that it has pre-populated
	 * collisions with all paths that map to new_path.  Do a quick check
	 * to ensure that's the case.
	 */
	collision_ent = collision_find_entry(collisions, new_path);
	if (collision_ent == NULL)
		BUG("collision_ent is NULL");
 
	/*
	 * Check for one-sided add/add/.../add conflicts, i.e.
	 * where implicit renames from the other side doing
	 * directory rename(s) can affect this side of history
	 * to put multiple paths into the same location.  Warn
	 * and bail on directory renames for such paths.
	 */
	if (collision_ent->reported_already) {
		clean = 0;
	} else if (tree_has_path(opt->repo, tree, new_path)) {
		collision_ent->reported_already = 1;
		strbuf_add_separated_string_list(&collision_paths, ", ",
						 &collision_ent->source_files);
		output(opt, 1, _("CONFLICT (implicit dir rename): Existing "
			       "file/dir at %s in the way of implicit "
			       "directory rename(s) putting the following "
			       "path(s) there: %s."),
		       new_path, collision_paths.buf);
		clean = 0;
	} else if (collision_ent->source_files.nr > 1) {
		collision_ent->reported_already = 1;
		strbuf_add_separated_string_list(&collision_paths, ", ",
						 &collision_ent->source_files);
		output(opt, 1, _("CONFLICT (implicit dir rename): Cannot map "
			       "more than one path to %s; implicit directory "
			       "renames tried to put these paths there: %s"),
		       new_path, collision_paths.buf);
		clean = 0;
	}
 
	/* Free memory we no longer need */
	strbuf_release(&collision_paths);
	if (!clean && new_path) {
		free(new_path);
		return NULL;
	}
 
	return new_path;
}
 
/*
 * There are a couple things we want to do at the directory level:
 *   1. Check for both sides renaming to the same thing, in order to avoid
 *      implicit renaming of files that should be left in place.  (See
 *      testcase 6b in t6043 for details.)
 *   2. Prune directory renames if there are still files left in the
 *      the original directory.  These represent a partial directory rename,
 *      i.e. a rename where only some of the files within the directory
 *      were renamed elsewhere.  (Technically, this could be done earlier
 *      in get_directory_renames(), except that would prevent us from
 *      doing the previous check and thus failing testcase 6b.)
 *   3. Check for rename/rename(1to2) conflicts (at the directory level).
 *      In the future, we could potentially record this info as well and
 *      omit reporting rename/rename(1to2) conflicts for each path within
 *      the affected directories, thus cleaning up the merge output.
 *   NOTE: We do NOT check for rename/rename(2to1) conflicts at the
 *         directory level, because merging directories is fine.  If it
 *         causes conflicts for files within those merged directories, then
 *         that should be detected at the individual path level.
 */
static void handle_directory_level_conflicts(struct merge_options *opt,
					     struct hashmap *dir_re_head,
					     struct tree *head,
					     struct hashmap *dir_re_merge,
					     struct tree *merge)
{
	struct hashmap_iter iter;
	struct dir_rename_entry *head_ent;
	struct dir_rename_entry *merge_ent;
 
	struct string_list remove_from_head = STRING_LIST_INIT_NODUP;
	struct string_list remove_from_merge = STRING_LIST_INIT_NODUP;
 
	hashmap_for_each_entry(dir_re_head, &iter, head_ent,
				ent /* member name */) {
		merge_ent = dir_rename_find_entry(dir_re_merge, head_ent->dir);
		if (merge_ent &&
		    !head_ent->non_unique_new_dir &&
		    !merge_ent->non_unique_new_dir &&
		    !strbuf_cmp(&head_ent->new_dir, &merge_ent->new_dir)) {
			/* 1. Renamed identically; remove it from both sides */
			string_list_append(&remove_from_head,
					   head_ent->dir)->util = head_ent;
			strbuf_release(&head_ent->new_dir);
			string_list_append(&remove_from_merge,
					   merge_ent->dir)->util = merge_ent;
			strbuf_release(&merge_ent->new_dir);
		} else if (tree_has_path(opt->repo, head, head_ent->dir)) {
			/* 2. This wasn't a directory rename after all */
			string_list_append(&remove_from_head,
					   head_ent->dir)->util = head_ent;
			strbuf_release(&head_ent->new_dir);
		}
	}
 
	remove_hashmap_entries(dir_re_head, &remove_from_head);
	remove_hashmap_entries(dir_re_merge, &remove_from_merge);
 
	hashmap_for_each_entry(dir_re_merge, &iter, merge_ent,
				ent /* member name */) {
		head_ent = dir_rename_find_entry(dir_re_head, merge_ent->dir);
		if (tree_has_path(opt->repo, merge, merge_ent->dir)) {
			/* 2. This wasn't a directory rename after all */
			string_list_append(&remove_from_merge,
					   merge_ent->dir)->util = merge_ent;
		} else if (head_ent &&
			   !head_ent->non_unique_new_dir &&
			   !merge_ent->non_unique_new_dir) {
			/* 3. rename/rename(1to2) */
			/*
			 * We can assume it's not rename/rename(1to1) because
			 * that was case (1), already checked above.  So we
			 * know that head_ent->new_dir and merge_ent->new_dir
			 * are different strings.
			 */
			output(opt, 1, _("CONFLICT (rename/rename): "
				       "Rename directory %s->%s in %s. "
				       "Rename directory %s->%s in %s"),
			       head_ent->dir, head_ent->new_dir.buf, opt->branch1,
			       head_ent->dir, merge_ent->new_dir.buf, opt->branch2);
			string_list_append(&remove_from_head,
					   head_ent->dir)->util = head_ent;
			strbuf_release(&head_ent->new_dir);
			string_list_append(&remove_from_merge,
					   merge_ent->dir)->util = merge_ent;
			strbuf_release(&merge_ent->new_dir);
		}
	}
 
	remove_hashmap_entries(dir_re_head, &remove_from_head);
	remove_hashmap_entries(dir_re_merge, &remove_from_merge);
}
 
static struct hashmap *get_directory_renames(struct diff_queue_struct *pairs)
{
	struct hashmap *dir_renames;
	struct hashmap_iter iter;
	struct dir_rename_entry *entry;
	int i;
 
	/*
	 * Typically, we think of a directory rename as all files from a
	 * certain directory being moved to a target directory.  However,
	 * what if someone first moved two files from the original
	 * directory in one commit, and then renamed the directory
	 * somewhere else in a later commit?  At merge time, we just know
	 * that files from the original directory went to two different
	 * places, and that the bulk of them ended up in the same place.
	 * We want each directory rename to represent where the bulk of the
	 * files from that directory end up; this function exists to find
	 * where the bulk of the files went.
	 *
	 * The first loop below simply iterates through the list of file
	 * renames, finding out how often each directory rename pair
	 * possibility occurs.
	 */
	dir_renames = xmalloc(sizeof(*dir_renames));
	dir_rename_init(dir_renames);
	for (i = 0; i < pairs->nr; ++i) {
		struct string_list_item *item;
		int *count;
		struct diff_filepair *pair = pairs->queue[i];
		char *old_dir, *new_dir;
 
		/* File not part of directory rename if it wasn't renamed */
		if (pair->status != 'R')
			continue;
 
		get_renamed_dir_portion(pair->one->path, pair->two->path,
					&old_dir,        &new_dir);
		if (!old_dir)
			/* Directory didn't change at all; ignore this one. */
			continue;
 
		entry = dir_rename_find_entry(dir_renames, old_dir);
		if (!entry) {
			entry = xmalloc(sizeof(*entry));
			dir_rename_entry_init(entry, old_dir);
			hashmap_put(dir_renames, &entry->ent);
		} else {
			free(old_dir);
		}
		item = string_list_lookup(&entry->possible_new_dirs, new_dir);
		if (!item) {
			item = string_list_insert(&entry->possible_new_dirs,
						  new_dir);
			item->util = xcalloc(1, sizeof(int));
		} else {
			free(new_dir);
		}
		count = item->util;
		*count += 1;
	}
 
	/*
	 * For each directory with files moved out of it, we find out which
	 * target directory received the most files so we can declare it to
	 * be the "winning" target location for the directory rename.  This
	 * winner gets recorded in new_dir.  If there is no winner
	 * (multiple target directories received the same number of files),
	 * we set non_unique_new_dir.  Once we've determined the winner (or
	 * that there is no winner), we no longer need possible_new_dirs.
	 */
	hashmap_for_each_entry(dir_renames, &iter, entry,
				ent /* member name */) {
		int max = 0;
		int bad_max = 0;
		char *best = NULL;
 
		for (i = 0; i < entry->possible_new_dirs.nr; i++) {
			int *count = entry->possible_new_dirs.items[i].util;
 
			if (*count == max)
				bad_max = max;
			else if (*count > max) {
				max = *count;
				best = entry->possible_new_dirs.items[i].string;
			}
		}
		if (bad_max == max)
			entry->non_unique_new_dir = 1;
		else {
			assert(entry->new_dir.len == 0);
			strbuf_addstr(&entry->new_dir, best);
		}
		/*
		 * The relevant directory sub-portion of the original full
		 * filepaths were xstrndup'ed before inserting into
		 * possible_new_dirs, and instead of manually iterating the
		 * list and free'ing each, just lie and tell
		 * possible_new_dirs that it did the strdup'ing so that it
		 * will free them for us.
		 */
		entry->possible_new_dirs.strdup_strings = 1;
		string_list_clear(&entry->possible_new_dirs, 1);
	}
 
	return dir_renames;
}
 
static struct dir_rename_entry *check_dir_renamed(const char *path,
						  struct hashmap *dir_renames)
{
	char *temp = xstrdup(path);
	char *end;
	struct dir_rename_entry *entry = NULL;
 
	while ((end = strrchr(temp, '/'))) {
		*end = '\0';
		entry = dir_rename_find_entry(dir_renames, temp);
		if (entry)
			break;
	}
	free(temp);
	return entry;
}
 
static void compute_collisions(struct hashmap *collisions,
			       struct hashmap *dir_renames,
			       struct diff_queue_struct *pairs)
{
	int i;
 
	/*
	 * Multiple files can be mapped to the same path due to directory
	 * renames done by the other side of history.  Since that other
	 * side of history could have merged multiple directories into one,
	 * if our side of history added the same file basename to each of
	 * those directories, then all N of them would get implicitly
	 * renamed by the directory rename detection into the same path,
	 * and we'd get an add/add/.../add conflict, and all those adds
	 * from *this* side of history.  This is not representable in the
	 * index, and users aren't going to easily be able to make sense of
	 * it.  So we need to provide a good warning about what's
	 * happening, and fall back to no-directory-rename detection
	 * behavior for those paths.
	 *
	 * See testcases 9e and all of section 5 from t6043 for examples.
	 */
	collision_init(collisions);
 
	for (i = 0; i < pairs->nr; ++i) {
		struct dir_rename_entry *dir_rename_ent;
		struct collision_entry *collision_ent;
		char *new_path;
		struct diff_filepair *pair = pairs->queue[i];
 
		if (pair->status != 'A' && pair->status != 'R')
			continue;
		dir_rename_ent = check_dir_renamed(pair->two->path,
						   dir_renames);
		if (!dir_rename_ent)
			continue;
 
		new_path = apply_dir_rename(dir_rename_ent, pair->two->path);
		if (!new_path)
			/*
			 * dir_rename_ent->non_unique_new_path is true, which
			 * means there is no directory rename for us to use,
			 * which means it won't cause us any additional
			 * collisions.
			 */
			continue;
		collision_ent = collision_find_entry(collisions, new_path);
		if (!collision_ent) {
			collision_ent = xcalloc(1,
						sizeof(struct collision_entry));
			hashmap_entry_init(&collision_ent->ent,
						strhash(new_path));
			hashmap_put(collisions, &collision_ent->ent);
			collision_ent->target_file = new_path;
		} else {
			free(new_path);
		}
		string_list_insert(&collision_ent->source_files,
				   pair->two->path);
	}
}
 
static char *check_for_directory_rename(struct merge_options *opt,
					const char *path,
					struct tree *tree,
					struct hashmap *dir_renames,
					struct hashmap *dir_rename_exclusions,
					struct hashmap *collisions,
					int *clean_merge)
{
	char *new_path = NULL;
	struct dir_rename_entry *entry = check_dir_renamed(path, dir_renames);
	struct dir_rename_entry *oentry = NULL;
 
	if (!entry)
		return new_path;
 
	/*
	 * This next part is a little weird.  We do not want to do an
	 * implicit rename into a directory we renamed on our side, because
	 * that will result in a spurious rename/rename(1to2) conflict.  An
	 * example:
	 *   Base commit: dumbdir/afile, otherdir/bfile
	 *   Side 1:      smrtdir/afile, otherdir/bfile
	 *   Side 2:      dumbdir/afile, dumbdir/bfile
	 * Here, while working on Side 1, we could notice that otherdir was
	 * renamed/merged to dumbdir, and change the diff_filepair for
	 * otherdir/bfile into a rename into dumbdir/bfile.  However, Side
	 * 2 will notice the rename from dumbdir to smrtdir, and do the
	 * transitive rename to move it from dumbdir/bfile to
	 * smrtdir/bfile.  That gives us bfile in dumbdir vs being in
	 * smrtdir, a rename/rename(1to2) conflict.  We really just want
	 * the file to end up in smrtdir.  And the way to achieve that is
	 * to not let Side1 do the rename to dumbdir, since we know that is
	 * the source of one of our directory renames.
	 *
	 * That's why oentry and dir_rename_exclusions is here.
	 *
	 * As it turns out, this also prevents N-way transient rename
	 * confusion; See testcases 9c and 9d of t6043.
	 */
	oentry = dir_rename_find_entry(dir_rename_exclusions, entry->new_dir.buf);
	if (oentry) {
		output(opt, 1, _("WARNING: Avoiding applying %s -> %s rename "
			       "to %s, because %s itself was renamed."),
		       entry->dir, entry->new_dir.buf, path, entry->new_dir.buf);
	} else {
		new_path = handle_path_level_conflicts(opt, path, entry,
						       collisions, tree);
		*clean_merge &= (new_path != NULL);
	}
 
	return new_path;
}
 
static void apply_directory_rename_modifications(struct merge_options *opt,
						 struct diff_filepair *pair,
						 char *new_path,
						 struct rename *re,
						 struct tree *tree,
						 struct tree *o_tree,
						 struct tree *a_tree,
						 struct tree *b_tree,
						 struct string_list *entries)
{
	struct string_list_item *item;
	int stage = (tree == a_tree ? 2 : 3);
	int update_wd;
 
	/*
	 * In all cases where we can do directory rename detection,
	 * unpack_trees() will have read pair->two->path into the
	 * index and the working copy.  We need to remove it so that
	 * we can instead place it at new_path.  It is guaranteed to
	 * not be untracked (unpack_trees() would have errored out
	 * saying the file would have been overwritten), but it might
	 * be dirty, though.
	 */
	update_wd = !was_dirty(opt, pair->two->path);
	if (!update_wd)
		output(opt, 1, _("Refusing to lose dirty file at %s"),
		       pair->two->path);
	remove_file(opt, 1, pair->two->path, !update_wd);
 
	/* Find or create a new re->dst_entry */
	item = string_list_lookup(entries, new_path);
	if (item) {
		/*
		 * Since we're renaming on this side of history, and it's
		 * due to a directory rename on the other side of history
		 * (which we only allow when the directory in question no
		 * longer exists on the other side of history), the
		 * original entry for re->dst_entry is no longer
		 * necessary...
		 */
		re->dst_entry->processed = 1;
 
		/*
		 * ...because we'll be using this new one.
		 */
		re->dst_entry = item->util;
	} else {
		/*
		 * re->dst_entry is for the before-dir-rename path, and we
		 * need it to hold information for the after-dir-rename
		 * path.  Before creating a new entry, we need to mark the
		 * old one as unnecessary (...unless it is shared by
		 * src_entry, i.e. this didn't use to be a rename, in which
		 * case we can just allow the normal processing to happen
		 * for it).
		 */
		if (pair->status == 'R')
			re->dst_entry->processed = 1;
 
		re->dst_entry = insert_stage_data(opt->repo, new_path,
						  o_tree, a_tree, b_tree,
						  entries);
		item = string_list_insert(entries, new_path);
		item->util = re->dst_entry;
	}
 
	/*
	 * Update the stage_data with the information about the path we are
	 * moving into place.  That slot will be empty and available for us
	 * to write to because of the collision checks in
	 * handle_path_level_conflicts().  In other words,
	 * re->dst_entry->stages[stage].oid will be the null_oid, so it's
	 * open for us to write to.
	 *
	 * It may be tempting to actually update the index at this point as
	 * well, using update_stages_for_stage_data(), but as per the big
	 * "NOTE" in update_stages(), doing so will modify the current
	 * in-memory index which will break calls to would_lose_untracked()
	 * that we need to make.  Instead, we need to just make sure that
	 * the various handle_rename_*() functions update the index
	 * explicitly rather than relying on unpack_trees() to have done it.
	 */
	get_tree_entry(opt->repo,
		       &tree->object.oid,
		       pair->two->path,
		       &re->dst_entry->stages[stage].oid,
		       &re->dst_entry->stages[stage].mode);
 
	/*
	 * Record the original change status (or 'type' of change).  If it
	 * was originally an add ('A'), this lets us differentiate later
	 * between a RENAME_DELETE conflict and RENAME_VIA_DIR (they
	 * otherwise look the same).  If it was originally a rename ('R'),
	 * this lets us remember and report accurately about the transitive
	 * renaming that occurred via the directory rename detection.  Also,
	 * record the original destination name.
	 */
	re->dir_rename_original_type = pair->status;
	re->dir_rename_original_dest = pair->two->path;
 
	/*
	 * We don't actually look at pair->status again, but it seems
	 * pedagogically correct to adjust it.
	 */
	pair->status = 'R';
 
	/*
	 * Finally, record the new location.
	 */
	pair->two->path = new_path;
}
 
/*
 * Get information of all renames which occurred in 'pairs', making use of
 * any implicit directory renames inferred from the other side of history.
 * We need the three trees in the merge ('o_tree', 'a_tree' and 'b_tree')
 * to be able to associate the correct cache entries with the rename
 * information; tree is always equal to either a_tree or b_tree.
 */
static struct string_list *get_renames(struct merge_options *opt,
				       const char *branch,
				       struct diff_queue_struct *pairs,
				       struct hashmap *dir_renames,
				       struct hashmap *dir_rename_exclusions,
				       struct tree *tree,
				       struct tree *o_tree,
				       struct tree *a_tree,
				       struct tree *b_tree,
				       struct string_list *entries,
				       int *clean_merge)
{
	int i;
	struct hashmap collisions;
	struct hashmap_iter iter;
	struct collision_entry *e;
	struct string_list *renames;
 
	compute_collisions(&collisions, dir_renames, pairs);
	renames = xcalloc(1, sizeof(struct string_list));
 
	for (i = 0; i < pairs->nr; ++i) {
		struct string_list_item *item;
		struct rename *re;
		struct diff_filepair *pair = pairs->queue[i];
		char *new_path; /* non-NULL only with directory renames */
 
		if (pair->status != 'A' && pair->status != 'R') {
			diff_free_filepair(pair);
			continue;
		}
		new_path = check_for_directory_rename(opt, pair->two->path, tree,
						      dir_renames,
						      dir_rename_exclusions,
						      &collisions,
						      clean_merge);
		if (pair->status != 'R' && !new_path) {
			diff_free_filepair(pair);
			continue;
		}
 
		re = xmalloc(sizeof(*re));
		re->processed = 0;
		re->pair = pair;
		re->branch = branch;
		re->dir_rename_original_type = '\0';
		re->dir_rename_original_dest = NULL;
		item = string_list_lookup(entries, re->pair->one->path);
		if (!item)
			re->src_entry = insert_stage_data(opt->repo,
					re->pair->one->path,
					o_tree, a_tree, b_tree, entries);
		else
			re->src_entry = item->util;
 
		item = string_list_lookup(entries, re->pair->two->path);
		if (!item)
			re->dst_entry = insert_stage_data(opt->repo,
					re->pair->two->path,
					o_tree, a_tree, b_tree, entries);
		else
			re->dst_entry = item->util;
		item = string_list_insert(renames, pair->one->path);
		item->util = re;
		if (new_path)
			apply_directory_rename_modifications(opt, pair, new_path,
							     re, tree, o_tree,
							     a_tree, b_tree,
							     entries);
	}
 
	hashmap_for_each_entry(&collisions, &iter, e,
				ent /* member name */) {
		free(e->target_file);
		string_list_clear(&e->source_files, 0);
	}
	hashmap_free_entries(&collisions, struct collision_entry, ent);
	return renames;
}
 
static int process_renames(struct merge_options *opt,
			   struct string_list *a_renames,
			   struct string_list *b_renames)
{
	int clean_merge = 1, i, j;
	struct string_list a_by_dst = STRING_LIST_INIT_NODUP;
	struct string_list b_by_dst = STRING_LIST_INIT_NODUP;
	const struct rename *sre;
 
	for (i = 0; i < a_renames->nr; i++) {
		sre = a_renames->items[i].util;
		string_list_insert(&a_by_dst, sre->pair->two->path)->util
			= (void *)sre;
	}
	for (i = 0; i < b_renames->nr; i++) {
		sre = b_renames->items[i].util;
		string_list_insert(&b_by_dst, sre->pair->two->path)->util
			= (void *)sre;
	}
 
	for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
		struct string_list *renames1, *renames2Dst;
		struct rename *ren1 = NULL, *ren2 = NULL;
		const char *ren1_src, *ren1_dst;
		struct string_list_item *lookup;
 
		if (i >= a_renames->nr) {
			ren2 = b_renames->items[j++].util;
		} else if (j >= b_renames->nr) {
			ren1 = a_renames->items[i++].util;
		} else {
			int compare = strcmp(a_renames->items[i].string,
					     b_renames->items[j].string);
			if (compare <= 0)
				ren1 = a_renames->items[i++].util;
			if (compare >= 0)
				ren2 = b_renames->items[j++].util;
		}
 
		/* TODO: refactor, so that 1/2 are not needed */
		if (ren1) {
			renames1 = a_renames;
			renames2Dst = &b_by_dst;
		} else {
			renames1 = b_renames;
			renames2Dst = &a_by_dst;
			SWAP(ren2, ren1);
		}
 
		if (ren1->processed)
			continue;
		ren1->processed = 1;
		ren1->dst_entry->processed = 1;
		/* BUG: We should only mark src_entry as processed if we
		 * are not dealing with a rename + add-source case.
		 */
		ren1->src_entry->processed = 1;
 
		ren1_src = ren1->pair->one->path;
		ren1_dst = ren1->pair->two->path;
 
		if (ren2) {
			/* One file renamed on both sides */
			const char *ren2_src = ren2->pair->one->path;
			const char *ren2_dst = ren2->pair->two->path;
			enum rename_type rename_type;
			if (strcmp(ren1_src, ren2_src) != 0)
				BUG("ren1_src != ren2_src");
			ren2->dst_entry->processed = 1;
			ren2->processed = 1;
			if (strcmp(ren1_dst, ren2_dst) != 0) {
				rename_type = RENAME_ONE_FILE_TO_TWO;
				clean_merge = 0;
			} else {
				rename_type = RENAME_ONE_FILE_TO_ONE;
				/* BUG: We should only remove ren1_src in
				 * the base stage (think of rename +
				 * add-source cases).
				 */
				remove_file(opt, 1, ren1_src, 1);
				update_entry(ren1->dst_entry,
					     ren1->pair->one,
					     ren1->pair->two,
					     ren2->pair->two);
			}
			setup_rename_conflict_info(rename_type, opt, ren1, ren2);
		} else if ((lookup = string_list_lookup(renames2Dst, ren1_dst))) {
			/* Two different files renamed to the same thing */
			char *ren2_dst;
			ren2 = lookup->util;
			ren2_dst = ren2->pair->two->path;
			if (strcmp(ren1_dst, ren2_dst) != 0)
				BUG("ren1_dst != ren2_dst");
 
			clean_merge = 0;
			ren2->processed = 1;
			/*
			 * BUG: We should only mark src_entry as processed
			 * if we are not dealing with a rename + add-source
			 * case.
			 */
			ren2->src_entry->processed = 1;
 
			setup_rename_conflict_info(RENAME_TWO_FILES_TO_ONE,
						   opt, ren1, ren2);
		} else {
			/* Renamed in 1, maybe changed in 2 */
			/* we only use sha1 and mode of these */
			struct diff_filespec src_other, dst_other;
			int try_merge;
 
			/*
			 * unpack_trees loads entries from common-commit
			 * into stage 1, from head-commit into stage 2, and
			 * from merge-commit into stage 3.  We keep track
			 * of which side corresponds to the rename.
			 */
			int renamed_stage = a_renames == renames1 ? 2 : 3;
			int other_stage =   a_renames == renames1 ? 3 : 2;
 
			/* BUG: We should only remove ren1_src in the base
			 * stage and in other_stage (think of rename +
			 * add-source case).
			 */
			remove_file(opt, 1, ren1_src,
				    renamed_stage == 2 || !was_tracked(opt, ren1_src));
 
			oidcpy(&src_other.oid,
			       &ren1->src_entry->stages[other_stage].oid);
			src_other.mode = ren1->src_entry->stages[other_stage].mode;
			oidcpy(&dst_other.oid,
			       &ren1->dst_entry->stages[other_stage].oid);
			dst_other.mode = ren1->dst_entry->stages[other_stage].mode;
			try_merge = 0;
 
			if (oideq(&src_other.oid, &null_oid) &&
			    ren1->dir_rename_original_type == 'A') {
				setup_rename_conflict_info(RENAME_VIA_DIR,
							   opt, ren1, NULL);
			} else if (oideq(&src_other.oid, &null_oid)) {
				setup_rename_conflict_info(RENAME_DELETE,
							   opt, ren1, NULL);
			} else if ((dst_other.mode == ren1->pair->two->mode) &&
				   oideq(&dst_other.oid, &ren1->pair->two->oid)) {
				/*
				 * Added file on the other side identical to
				 * the file being renamed: clean merge.
				 * Also, there is no need to overwrite the
				 * file already in the working copy, so call
				 * update_file_flags() instead of
				 * update_file().
				 */
				if (update_file_flags(opt,
						      ren1->pair->two,
						      ren1_dst,
						      1, /* update_cache */
						      0  /* update_wd    */))
					clean_merge = -1;
			} else if (!oideq(&dst_other.oid, &null_oid)) {
				/*
				 * Probably not a clean merge, but it's
				 * premature to set clean_merge to 0 here,
				 * because if the rename merges cleanly and
				 * the merge exactly matches the newly added
				 * file, then the merge will be clean.
				 */
				setup_rename_conflict_info(RENAME_ADD,
							   opt, ren1, NULL);
			} else
				try_merge = 1;
 
			if (clean_merge < 0)
				goto cleanup_and_return;
			if (try_merge) {
				struct diff_filespec *o, *a, *b;
				src_other.path = (char *)ren1_src;
 
				o = ren1->pair->one;
				if (a_renames == renames1) {
					a = ren1->pair->two;
					b = &src_other;
				} else {
					b = ren1->pair->two;
					a = &src_other;
				}
				update_entry(ren1->dst_entry, o, a, b);
				setup_rename_conflict_info(RENAME_NORMAL,
							   opt, ren1, NULL);
			}
		}
	}
cleanup_and_return:
	string_list_clear(&a_by_dst, 0);
	string_list_clear(&b_by_dst, 0);
 
	return clean_merge;
}
 
struct rename_info {
	struct string_list *head_renames;
	struct string_list *merge_renames;
};
 
static void initial_cleanup_rename(struct diff_queue_struct *pairs,
				   struct hashmap *dir_renames)
{
	struct hashmap_iter iter;
	struct dir_rename_entry *e;
 
	hashmap_for_each_entry(dir_renames, &iter, e,
				ent /* member name */) {
		free(e->dir);
		strbuf_release(&e->new_dir);
		/* possible_new_dirs already cleared in get_directory_renames */
	}
	hashmap_free_entries(dir_renames, struct dir_rename_entry, ent);
	free(dir_renames);
 
	free(pairs->queue);
	free(pairs);
}
 
static int detect_and_process_renames(struct merge_options *opt,
				      struct tree *common,
				      struct tree *head,
				      struct tree *merge,
				      struct string_list *entries,
				      struct rename_info *ri)
{
	struct diff_queue_struct *head_pairs, *merge_pairs;
	struct hashmap *dir_re_head, *dir_re_merge;
	int clean = 1;
 
	ri->head_renames = NULL;
	ri->merge_renames = NULL;
 
	if (!merge_detect_rename(opt))
		return 1;
 
	head_pairs = get_diffpairs(opt, common, head);
	merge_pairs = get_diffpairs(opt, common, merge);
 
	if ((opt->detect_directory_renames == MERGE_DIRECTORY_RENAMES_TRUE) ||
	    (opt->detect_directory_renames == MERGE_DIRECTORY_RENAMES_CONFLICT &&
	     !opt->priv->call_depth)) {
		dir_re_head = get_directory_renames(head_pairs);
		dir_re_merge = get_directory_renames(merge_pairs);
 
		handle_directory_level_conflicts(opt,
						 dir_re_head, head,
						 dir_re_merge, merge);
	} else {
		dir_re_head  = xmalloc(sizeof(*dir_re_head));
		dir_re_merge = xmalloc(sizeof(*dir_re_merge));
		dir_rename_init(dir_re_head);
		dir_rename_init(dir_re_merge);
	}
 
	ri->head_renames  = get_renames(opt, opt->branch1, head_pairs,
					dir_re_merge, dir_re_head, head,
					common, head, merge, entries,
					&clean);
	if (clean < 0)
		goto cleanup;
	ri->merge_renames = get_renames(opt, opt->branch2, merge_pairs,
					dir_re_head, dir_re_merge, merge,
					common, head, merge, entries,
					&clean);
	if (clean < 0)
		goto cleanup;
	clean &= process_renames(opt, ri->head_renames, ri->merge_renames);
 
cleanup:
	/*
	 * Some cleanup is deferred until cleanup_renames() because the
	 * data structures are still needed and referenced in
	 * process_entry().  But there are a few things we can free now.
	 */
	initial_cleanup_rename(head_pairs, dir_re_head);
	initial_cleanup_rename(merge_pairs, dir_re_merge);
 
	return clean;
}
 
static void final_cleanup_rename(struct string_list *rename)
{
	const struct rename *re;
	int i;
 
	if (rename == NULL)
		return;
 
	for (i = 0; i < rename->nr; i++) {
		re = rename->items[i].util;
		diff_free_filepair(re->pair);
	}
	string_list_clear(rename, 1);
	free(rename);
}
 
static void final_cleanup_renames(struct rename_info *re_info)
{
	final_cleanup_rename(re_info->head_renames);
	final_cleanup_rename(re_info->merge_renames);
}
 
static int read_oid_strbuf(struct merge_options *opt,
			   const struct object_id *oid,
			   struct strbuf *dst)
{
	void *buf;
	enum object_type type;
	unsigned long size;
	buf = read_object_file(oid, &type, &size);
	if (!buf)
		return err(opt, _("cannot read object %s"), oid_to_hex(oid));
	if (type != OBJ_BLOB) {
		free(buf);
		return err(opt, _("object %s is not a blob"), oid_to_hex(oid));
	}
	strbuf_attach(dst, buf, size, size + 1);
	return 0;
}
 
static int blob_unchanged(struct merge_options *opt,
			  const struct diff_filespec *o,
			  const struct diff_filespec *a,
			  int renormalize, const char *path)
{
	struct strbuf obuf = STRBUF_INIT;
	struct strbuf abuf = STRBUF_INIT;
	int ret = 0; /* assume changed for safety */
	const struct index_state *idx = opt->repo->index;
 
	if (a->mode != o->mode)
		return 0;
	if (oideq(&o->oid, &a->oid))
		return 1;
	if (!renormalize)
		return 0;
 
	if (read_oid_strbuf(opt, &o->oid, &obuf) ||
	    read_oid_strbuf(opt, &a->oid, &abuf))
		goto error_return;
	/*
	 * Note: binary | is used so that both renormalizations are
	 * performed.  Comparison can be skipped if both files are
	 * unchanged since their sha1s have already been compared.
	 */
	if (renormalize_buffer(idx, path, obuf.buf, obuf.len, &obuf) |
	    renormalize_buffer(idx, path, abuf.buf, abuf.len, &abuf))
		ret = (obuf.len == abuf.len && !memcmp(obuf.buf, abuf.buf, obuf.len));
 
error_return:
	strbuf_release(&obuf);
	strbuf_release(&abuf);
	return ret;
}
 
static int handle_modify_delete(struct merge_options *opt,
				const char *path,
				const struct diff_filespec *o,
				const struct diff_filespec *a,
				const struct diff_filespec *b)
{
	const char *modify_branch, *delete_branch;
	const struct diff_filespec *changed;
 
	if (is_valid(a)) {
		modify_branch = opt->branch1;
		delete_branch = opt->branch2;
		changed = a;
	} else {
		modify_branch = opt->branch2;
		delete_branch = opt->branch1;
		changed = b;
	}
 
	return handle_change_delete(opt,
				    path, NULL,
				    o, changed,
				    modify_branch, delete_branch,
				    _("modify"), _("modified"));
}
 
static int handle_content_merge(struct merge_file_info *mfi,
				struct merge_options *opt,
				const char *path,
				int is_dirty,
				const struct diff_filespec *o,
				const struct diff_filespec *a,
				const struct diff_filespec *b,
				struct rename_conflict_info *ci)
{
	const char *reason = _("content");
	unsigned df_conflict_remains = 0;
 
	if (!is_valid(o))
		reason = _("add/add");
 
	assert(o->path && a->path && b->path);
	if (ci && dir_in_way(opt->repo->index, path, !opt->priv->call_depth,
			     S_ISGITLINK(ci->ren1->pair->two->mode)))
		df_conflict_remains = 1;
 
	if (merge_mode_and_contents(opt, o, a, b, path,
				    opt->branch1, opt->branch2,
				    opt->priv->call_depth * 2, mfi))
		return -1;
 
	/*
	 * We can skip updating the working tree file iff:
	 *   a) The merge is clean
	 *   b) The merge matches what was in HEAD (content, mode, pathname)
	 *   c) The target path is usable (i.e. not involved in D/F conflict)
	 */
	if (mfi->clean && was_tracked_and_matches(opt, path, &mfi->blob) &&
	    !df_conflict_remains) {
		int pos;
		struct cache_entry *ce;
 
		output(opt, 3, _("Skipped %s (merged same as existing)"), path);
		if (add_cacheinfo(opt, &mfi->blob, path,
				  0, (!opt->priv->call_depth && !is_dirty), 0))
			return -1;
		/*
		 * However, add_cacheinfo() will delete the old cache entry
		 * and add a new one.  We need to copy over any skip_worktree
		 * flag to avoid making the file appear as if it were
		 * deleted by the user.
		 */
		pos = index_name_pos(&opt->priv->orig_index, path, strlen(path));
		ce = opt->priv->orig_index.cache[pos];
		if (ce_skip_worktree(ce)) {
			pos = index_name_pos(opt->repo->index, path, strlen(path));
			ce = opt->repo->index->cache[pos];
			ce->ce_flags |= CE_SKIP_WORKTREE;
		}
		return mfi->clean;
	}
 
	if (!mfi->clean) {
		if (S_ISGITLINK(mfi->blob.mode))
			reason = _("submodule");
		output(opt, 1, _("CONFLICT (%s): Merge conflict in %s"),
				reason, path);
		if (ci && !df_conflict_remains)
			if (update_stages(opt, path, o, a, b))
				return -1;
	}
 
	if (df_conflict_remains || is_dirty) {
		char *new_path;
		if (opt->priv->call_depth) {
			remove_file_from_index(opt->repo->index, path);
		} else {
			if (!mfi->clean) {
				if (update_stages(opt, path, o, a, b))
					return -1;
			} else {
				int file_from_stage2 = was_tracked(opt, path);
 
				if (update_stages(opt, path, NULL,
						  file_from_stage2 ? &mfi->blob : NULL,
						  file_from_stage2 ? NULL : &mfi->blob))
					return -1;
			}
 
		}
		new_path = unique_path(opt, path, ci->ren1->branch);
		if (is_dirty) {
			output(opt, 1, _("Refusing to lose dirty file at %s"),
			       path);
		}
		output(opt, 1, _("Adding as %s instead"), new_path);
		if (update_file(opt, 0, &mfi->blob, new_path)) {
			free(new_path);
			return -1;
		}
		free(new_path);
		mfi->clean = 0;
	} else if (update_file(opt, mfi->clean, &mfi->blob, path))
		return -1;
	return !is_dirty && mfi->clean;
}
 
static int handle_rename_normal(struct merge_options *opt,
				const char *path,
				const struct diff_filespec *o,
				const struct diff_filespec *a,
				const struct diff_filespec *b,
				struct rename_conflict_info *ci)
{
	struct rename *ren = ci->ren1;
	struct merge_file_info mfi;
	int clean;
	int side = (ren->branch == opt->branch1 ? 2 : 3);
 
	/* Merge the content and write it out */
	clean = handle_content_merge(&mfi, opt, path, was_dirty(opt, path),
				     o, a, b, ci);
 
	if (clean &&
	    opt->detect_directory_renames == MERGE_DIRECTORY_RENAMES_CONFLICT &&
	    ren->dir_rename_original_dest) {
		if (update_stages(opt, path,
				  NULL,
				  side == 2 ? &mfi.blob : NULL,
				  side == 2 ? NULL : &mfi.blob))
			return -1;
		clean = 0; /* not clean, but conflicted */
	}
	return clean;
}
 
static void dir_rename_warning(const char *msg,
			       int is_add,
			       int clean,
			       struct merge_options *opt,
			       struct rename *ren)
{
	const char *other_branch;
	other_branch = (ren->branch == opt->branch1 ?
			opt->branch2 : opt->branch1);
	if (is_add) {
		output(opt, clean ? 2 : 1, msg,
		       ren->pair->one->path, ren->branch,
		       other_branch, ren->pair->two->path);
		return;
	}
	output(opt, clean ? 2 : 1, msg,
	       ren->pair->one->path, ren->dir_rename_original_dest, ren->branch,
	       other_branch, ren->pair->two->path);
}
static int warn_about_dir_renamed_entries(struct merge_options *opt,
					  struct rename *ren)
{
	const char *msg;
	int clean = 1, is_add;
 
	if (!ren)
		return clean;
 
	/* Return early if ren was not affected/created by a directory rename */
	if (!ren->dir_rename_original_dest)
		return clean;
 
	/* Sanity checks */
	assert(opt->detect_directory_renames > MERGE_DIRECTORY_RENAMES_NONE);
	assert(ren->dir_rename_original_type == 'A' ||
	       ren->dir_rename_original_type == 'R');
 
	/* Check whether to treat directory renames as a conflict */
	clean = (opt->detect_directory_renames == MERGE_DIRECTORY_RENAMES_TRUE);
 
	is_add = (ren->dir_rename_original_type == 'A');
	if (ren->dir_rename_original_type == 'A' && clean) {
		msg = _("Path updated: %s added in %s inside a "
			"directory that was renamed in %s; moving it to %s.");
	} else if (ren->dir_rename_original_type == 'A' && !clean) {
		msg = _("CONFLICT (file location): %s added in %s "
			"inside a directory that was renamed in %s, "
			"suggesting it should perhaps be moved to %s.");
	} else if (ren->dir_rename_original_type == 'R' && clean) {
		msg = _("Path updated: %s renamed to %s in %s, inside a "
			"directory that was renamed in %s; moving it to %s.");
	} else if (ren->dir_rename_original_type == 'R' && !clean) {
		msg = _("CONFLICT (file location): %s renamed to %s in %s, "
			"inside a directory that was renamed in %s, "
			"suggesting it should perhaps be moved to %s.");
	} else {
		BUG("Impossible dir_rename_original_type/clean combination");
	}
	dir_rename_warning(msg, is_add, clean, opt, ren);
 
	return clean;
}
 
/* Per entry merge function */
static int process_entry(struct merge_options *opt,
			 const char *path, struct stage_data *entry)
{
	int clean_merge = 1;
	int normalize = opt->renormalize;
 
	struct diff_filespec *o = &entry->stages[1];
	struct diff_filespec *a = &entry->stages[2];
	struct diff_filespec *b = &entry->stages[3];
	int o_valid = is_valid(o);
	int a_valid = is_valid(a);
	int b_valid = is_valid(b);
	o->path = a->path = b->path = (char*)path;
 
	entry->processed = 1;
	if (entry->rename_conflict_info) {
		struct rename_conflict_info *ci = entry->rename_conflict_info;
		struct diff_filespec *temp;
		int path_clean;
 
		path_clean = warn_about_dir_renamed_entries(opt, ci->ren1);
		path_clean &= warn_about_dir_renamed_entries(opt, ci->ren2);
 
		/*
		 * For cases with a single rename, {o,a,b}->path have all been
		 * set to the rename target path; we need to set two of these
		 * back to the rename source.
		 * For rename/rename conflicts, we'll manually fix paths below.
		 */
		temp = (opt->branch1 == ci->ren1->branch) ? b : a;
		o->path = temp->path = ci->ren1->pair->one->path;
		if (ci->ren2) {
			assert(opt->branch1 == ci->ren1->branch);
		}
 
		switch (ci->rename_type) {
		case RENAME_NORMAL:
		case RENAME_ONE_FILE_TO_ONE:
			clean_merge = handle_rename_normal(opt, path, o, a, b,
							   ci);
			break;
		case RENAME_VIA_DIR:
			clean_merge = handle_rename_via_dir(opt, ci);
			break;
		case RENAME_ADD:
			/*
			 * Probably unclean merge, but if the renamed file
			 * merges cleanly and the result can then be
			 * two-way merged cleanly with the added file, I
			 * guess it's a clean merge?
			 */
			clean_merge = handle_rename_add(opt, ci);
			break;
		case RENAME_DELETE:
			clean_merge = 0;
			if (handle_rename_delete(opt, ci))
				clean_merge = -1;
			break;
		case RENAME_ONE_FILE_TO_TWO:
			/*
			 * Manually fix up paths; note:
			 * ren[12]->pair->one->path are equal.
			 */
			o->path = ci->ren1->pair->one->path;
			a->path = ci->ren1->pair->two->path;
			b->path = ci->ren2->pair->two->path;
 
			clean_merge = 0;
			if (handle_rename_rename_1to2(opt, ci))
				clean_merge = -1;
			break;
		case RENAME_TWO_FILES_TO_ONE:
			/*
			 * Manually fix up paths; note,
			 * ren[12]->pair->two->path are actually equal.
			 */
			o->path = NULL;
			a->path = ci->ren1->pair->two->path;
			b->path = ci->ren2->pair->two->path;
 
			/*
			 * Probably unclean merge, but if the two renamed
			 * files merge cleanly and the two resulting files
			 * can then be two-way merged cleanly, I guess it's
			 * a clean merge?
			 */
			clean_merge = handle_rename_rename_2to1(opt, ci);
			break;
		default:
			entry->processed = 0;
			break;
		}
		if (path_clean < clean_merge)
			clean_merge = path_clean;
	} else if (o_valid && (!a_valid || !b_valid)) {
		/* Case A: Deleted in one */
		if ((!a_valid && !b_valid) ||
		    (!b_valid && blob_unchanged(opt, o, a, normalize, path)) ||
		    (!a_valid && blob_unchanged(opt, o, b, normalize, path))) {
			/* Deleted in both or deleted in one and
			 * unchanged in the other */
			if (a_valid)
				output(opt, 2, _("Removing %s"), path);
			/* do not touch working file if it did not exist */
			remove_file(opt, 1, path, !a_valid);
		} else {
			/* Modify/delete; deleted side may have put a directory in the way */
			clean_merge = 0;
			if (handle_modify_delete(opt, path, o, a, b))
				clean_merge = -1;
		}
	} else if ((!o_valid && a_valid && !b_valid) ||
		   (!o_valid && !a_valid && b_valid)) {
		/* Case B: Added in one. */
		/* [nothing|directory] -> ([nothing|directory], file) */
 
		const char *add_branch;
		const char *other_branch;
		const char *conf;
		const struct diff_filespec *contents;
 
		if (a_valid) {
			add_branch = opt->branch1;
			other_branch = opt->branch2;
			contents = a;
			conf = _("file/directory");
		} else {
			add_branch = opt->branch2;
			other_branch = opt->branch1;
			contents = b;
			conf = _("directory/file");
		}
		if (dir_in_way(opt->repo->index, path,
			       !opt->priv->call_depth && !S_ISGITLINK(a->mode),
			       0)) {
			char *new_path = unique_path(opt, path, add_branch);
			clean_merge = 0;
			output(opt, 1, _("CONFLICT (%s): There is a directory with name %s in %s. "
			       "Adding %s as %s"),
			       conf, path, other_branch, path, new_path);
			if (update_file(opt, 0, contents, new_path))
				clean_merge = -1;
			else if (opt->priv->call_depth)
				remove_file_from_index(opt->repo->index, path);
			free(new_path);
		} else {
			output(opt, 2, _("Adding %s"), path);
			/* do not overwrite file if already present */
			if (update_file_flags(opt, contents, path, 1, !a_valid))
				clean_merge = -1;
		}
	} else if (a_valid && b_valid) {
		if (!o_valid) {
			/* Case C: Added in both (check for same permissions) */
			output(opt, 1,
			       _("CONFLICT (add/add): Merge conflict in %s"),
			       path);
			clean_merge = handle_file_collision(opt,
							    path, NULL, NULL,
							    opt->branch1,
							    opt->branch2,
							    a, b);
		} else {
			/* case D: Modified in both, but differently. */
			struct merge_file_info mfi;
			int is_dirty = 0; /* unpack_trees would have bailed if dirty */
			clean_merge = handle_content_merge(&mfi, opt, path,
							   is_dirty,
							   o, a, b, NULL);
		}
	} else if (!o_valid && !a_valid && !b_valid) {
		/*
		 * this entry was deleted altogether. a_mode == 0 means
		 * we had that path and want to actively remove it.
		 */
		remove_file(opt, 1, path, !a->mode);
	} else
		BUG("fatal merge failure, shouldn't happen.");
 
	return clean_merge;
}
 
static int merge_trees_internal(struct merge_options *opt,
				struct tree *head,
				struct tree *merge,
				struct tree *merge_base,
				struct tree **result)
{
	struct index_state *istate = opt->repo->index;
	int code, clean;
 
	if (opt->subtree_shift) {
		merge = shift_tree_object(opt->repo, head, merge,
					  opt->subtree_shift);
		merge_base = shift_tree_object(opt->repo, head, merge_base,
					       opt->subtree_shift);
	}
 
	if (oideq(&merge_base->object.oid, &merge->object.oid)) {
		output(opt, 0, _("Already up to date!"));
		*result = head;
		return 1;
	}
 
	code = unpack_trees_start(opt, merge_base, head, merge);
 
	if (code != 0) {
		if (show(opt, 4) || opt->priv->call_depth)
			err(opt, _("merging of trees %s and %s failed"),
			    oid_to_hex(&head->object.oid),
			    oid_to_hex(&merge->object.oid));
		unpack_trees_finish(opt);
		return -1;
	}
 
	if (unmerged_index(istate)) {
		struct string_list *entries;
		struct rename_info re_info;
		int i;
		/*
		 * Only need the hashmap while processing entries, so
		 * initialize it here and free it when we are done running
		 * through the entries. Keeping it in the merge_options as
		 * opposed to decaring a local hashmap is for convenience
		 * so that we don't have to pass it to around.
		 */
		hashmap_init(&opt->priv->current_file_dir_set, path_hashmap_cmp,
			     NULL, 512);
		get_files_dirs(opt, head);
		get_files_dirs(opt, merge);
 
		entries = get_unmerged(opt->repo->index);
		clean = detect_and_process_renames(opt, merge_base, head, merge,
						   entries, &re_info);
		record_df_conflict_files(opt, entries);
		if (clean < 0)
			goto cleanup;
		for (i = entries->nr-1; 0 <= i; i--) {
			const char *path = entries->items[i].string;
			struct stage_data *e = entries->items[i].util;
			if (!e->processed) {
				int ret = process_entry(opt, path, e);
				if (!ret)
					clean = 0;
				else if (ret < 0) {
					clean = ret;
					goto cleanup;
				}
			}
		}
		for (i = 0; i < entries->nr; i++) {
			struct stage_data *e = entries->items[i].util;
			if (!e->processed)
				BUG("unprocessed path??? %s",
				    entries->items[i].string);
		}
 
	cleanup:
		final_cleanup_renames(&re_info);
 
		string_list_clear(entries, 1);
		free(entries);
 
		hashmap_free_entries(&opt->priv->current_file_dir_set,
					struct path_hashmap_entry, e);
 
		if (clean < 0) {
			unpack_trees_finish(opt);
			return clean;
		}
	}
	else
		clean = 1;
 
	unpack_trees_finish(opt);
 
	if (opt->priv->call_depth &&
	    !(*result = write_in_core_index_as_tree(opt->repo)))
		return -1;
 
	return clean;
}
 
static struct commit_list *reverse_commit_list(struct commit_list *list)
{
	struct commit_list *next = NULL, *current, *backup;
	for (current = list; current; current = backup) {
		backup = current->next;
		current->next = next;
		next = current;
	}
	return next;
}
 
/*
 * Merge the commits h1 and h2, return the resulting virtual
 * commit object and a flag indicating the cleanness of the merge.
 */
static int merge_recursive_internal(struct merge_options *opt,
				    struct commit *h1,
				    struct commit *h2,
				    struct commit_list *merge_bases,
				    struct commit **result)
{
	struct commit_list *iter;
	struct commit *merged_merge_bases;
	struct tree *result_tree;
	int clean;
	const char *ancestor_name;
	struct strbuf merge_base_abbrev = STRBUF_INIT;
 
	if (show(opt, 4)) {
		output(opt, 4, _("Merging:"));
		output_commit_title(opt, h1);
		output_commit_title(opt, h2);
	}
 
	if (!merge_bases) {
		merge_bases = get_merge_bases(h1, h2);
		merge_bases = reverse_commit_list(merge_bases);
	}
 
	if (show(opt, 5)) {
		unsigned cnt = commit_list_count(merge_bases);
 
		output(opt, 5, Q_("found %u common ancestor:",
				"found %u common ancestors:", cnt), cnt);
		for (iter = merge_bases; iter; iter = iter->next)
			output_commit_title(opt, iter->item);
	}
 
	merged_merge_bases = pop_commit(&merge_bases);
	if (merged_merge_bases == NULL) {
		/* if there is no common ancestor, use an empty tree */
		struct tree *tree;
 
		tree = lookup_tree(opt->repo, opt->repo->hash_algo->empty_tree);
		merged_merge_bases = make_virtual_commit(opt->repo, tree,
							 "ancestor");
		ancestor_name = "empty tree";
	} else if (opt->ancestor && !opt->priv->call_depth) {
		ancestor_name = opt->ancestor;
	} else if (merge_bases) {
		ancestor_name = "merged common ancestors";
	} else {
		strbuf_add_unique_abbrev(&merge_base_abbrev,
					 &merged_merge_bases->object.oid,
					 DEFAULT_ABBREV);
		ancestor_name = merge_base_abbrev.buf;
	}
 
	for (iter = merge_bases; iter; iter = iter->next) {
		const char *saved_b1, *saved_b2;
		opt->priv->call_depth++;
		/*
		 * When the merge fails, the result contains files
		 * with conflict markers. The cleanness flag is
		 * ignored (unless indicating an error), it was never
		 * actually used, as result of merge_trees has always
		 * overwritten it: the committed "conflicts" were
		 * already resolved.
		 */
		discard_index(opt->repo->index);
		saved_b1 = opt->branch1;
		saved_b2 = opt->branch2;
		opt->branch1 = "Temporary merge branch 1";
		opt->branch2 = "Temporary merge branch 2";
		if (merge_recursive_internal(opt, merged_merge_bases, iter->item,
					     NULL, &merged_merge_bases) < 0)
			return -1;
		opt->branch1 = saved_b1;
		opt->branch2 = saved_b2;
		opt->priv->call_depth--;
 
		if (!merged_merge_bases)
			return err(opt, _("merge returned no commit"));
	}
 
	discard_index(opt->repo->index);
	if (!opt->priv->call_depth)
		repo_read_index(opt->repo);
 
	opt->ancestor = ancestor_name;
	clean = merge_trees_internal(opt,
				     repo_get_commit_tree(opt->repo, h1),
				     repo_get_commit_tree(opt->repo, h2),
				     repo_get_commit_tree(opt->repo,
							  merged_merge_bases),
				     &result_tree);
	strbuf_release(&merge_base_abbrev);
	opt->ancestor = NULL;  /* avoid accidental re-use of opt->ancestor */
	if (clean < 0) {
		flush_output(opt);
		return clean;
	}
 
	if (opt->priv->call_depth) {
		*result = make_virtual_commit(opt->repo, result_tree,
					      "merged tree");
		commit_list_insert(h1, &(*result)->parents);
		commit_list_insert(h2, &(*result)->parents->next);
	}
	return clean;
}
 
static int merge_start(struct merge_options *opt, struct tree *head)
{
	struct strbuf sb = STRBUF_INIT;
 
	/* Sanity checks on opt */
	assert(opt->repo);
 
	assert(opt->branch1 && opt->branch2);
 
	assert(opt->detect_renames >= -1 &&
	       opt->detect_renames <= DIFF_DETECT_COPY);
	assert(opt->detect_directory_renames >= MERGE_DIRECTORY_RENAMES_NONE &&
	       opt->detect_directory_renames <= MERGE_DIRECTORY_RENAMES_TRUE);
	assert(opt->rename_limit >= -1);
	assert(opt->rename_score >= 0 && opt->rename_score <= MAX_SCORE);
	assert(opt->show_rename_progress >= 0 && opt->show_rename_progress <= 1);
 
	assert(opt->xdl_opts >= 0);
	assert(opt->recursive_variant >= MERGE_VARIANT_NORMAL &&
	       opt->recursive_variant <= MERGE_VARIANT_THEIRS);
 
	assert(opt->verbosity >= 0 && opt->verbosity <= 5);
	assert(opt->buffer_output <= 2);
	assert(opt->obuf.len == 0);
 
	assert(opt->priv == NULL);
 
	/* Sanity check on repo state; index must match head */
	if (repo_index_has_changes(opt->repo, head, &sb)) {
		err(opt, _("Your local changes to the following files would be overwritten by merge:\n  %s"),
		    sb.buf);
		strbuf_release(&sb);
		return -1;
	}
 
	opt->priv = xcalloc(1, sizeof(*opt->priv));
	string_list_init(&opt->priv->df_conflict_file_set, 1);
	return 0;
}
 
static void merge_finalize(struct merge_options *opt)
{
	flush_output(opt);
	if (!opt->priv->call_depth && opt->buffer_output < 2)
		strbuf_release(&opt->obuf);
	if (show(opt, 2))
		diff_warn_rename_limit("merge.renamelimit",
				       opt->priv->needed_rename_limit, 0);
	FREE_AND_NULL(opt->priv);
}
 
int merge_trees(struct merge_options *opt,
		struct tree *head,
		struct tree *merge,
		struct tree *merge_base)
{
	int clean;
	struct tree *ignored;
 
	assert(opt->ancestor != NULL);
 
	if (merge_start(opt, head))
		return -1;
	clean = merge_trees_internal(opt, head, merge, merge_base, &ignored);
	merge_finalize(opt);
 
	return clean;
}
 
int merge_recursive(struct merge_options *opt,
		    struct commit *h1,
		    struct commit *h2,
		    struct commit_list *merge_bases,
		    struct commit **result)
{
	int clean;
 
	assert(opt->ancestor == NULL ||
	       !strcmp(opt->ancestor, "constructed merge base"));
 
	if (merge_start(opt, repo_get_commit_tree(opt->repo, h1)))
		return -1;
	clean = merge_recursive_internal(opt, h1, h2, merge_bases, result);
	merge_finalize(opt);
 
	return clean;
}
 
static struct commit *get_ref(struct repository *repo,
			      const struct object_id *oid,
			      const char *name)
{
	struct object *object;
 
	object = deref_tag(repo, parse_object(repo, oid),
			   name, strlen(name));
	if (!object)
		return NULL;
	if (object->type == OBJ_TREE)
		return make_virtual_commit(repo, (struct tree*)object, name);
	if (object->type != OBJ_COMMIT)
		return NULL;
	if (parse_commit((struct commit *)object))
		return NULL;
	return (struct commit *)object;
}
 
int merge_recursive_generic(struct merge_options *opt,
			    const struct object_id *head,
			    const struct object_id *merge,
			    int num_merge_bases,
			    const struct object_id **merge_bases,
			    struct commit **result)
{
	int clean;
	struct lock_file lock = LOCK_INIT;
	struct commit *head_commit = get_ref(opt->repo, head, opt->branch1);
	struct commit *next_commit = get_ref(opt->repo, merge, opt->branch2);
	struct commit_list *ca = NULL;
 
	if (merge_bases) {
		int i;
		for (i = 0; i < num_merge_bases; ++i) {
			struct commit *base;
			if (!(base = get_ref(opt->repo, merge_bases[i],
					     oid_to_hex(merge_bases[i]))))
				return err(opt, _("Could not parse object '%s'"),
					   oid_to_hex(merge_bases[i]));
			commit_list_insert(base, &ca);
		}
		if (num_merge_bases == 1)
			opt->ancestor = "constructed merge base";
	}
 
	repo_hold_locked_index(opt->repo, &lock, LOCK_DIE_ON_ERROR);
	clean = merge_recursive(opt, head_commit, next_commit, ca,
				result);
	if (clean < 0) {
		rollback_lock_file(&lock);
		return clean;
	}
 
	if (write_locked_index(opt->repo->index, &lock,
			       COMMIT_LOCK | SKIP_IF_UNCHANGED))
		return err(opt, _("Unable to write index."));
 
	return clean ? 0 : 1;
}
 
static void merge_recursive_config(struct merge_options *opt)
{
	char *value = NULL;
	git_config_get_int("merge.verbosity", &opt->verbosity);
	git_config_get_int("diff.renamelimit", &opt->rename_limit);
	git_config_get_int("merge.renamelimit", &opt->rename_limit);
	if (!git_config_get_string("diff.renames", &value)) {
		opt->detect_renames = git_config_rename("diff.renames", value);
		free(value);
	}
	if (!git_config_get_string("merge.renames", &value)) {
		opt->detect_renames = git_config_rename("merge.renames", value);
		free(value);
	}
	if (!git_config_get_string("merge.directoryrenames", &value)) {
		int boolval = git_parse_maybe_bool(value);
		if (0 <= boolval) {
			opt->detect_directory_renames = boolval ?
				MERGE_DIRECTORY_RENAMES_TRUE :
				MERGE_DIRECTORY_RENAMES_NONE;
		} else if (!strcasecmp(value, "conflict")) {
			opt->detect_directory_renames =
				MERGE_DIRECTORY_RENAMES_CONFLICT;
		} /* avoid erroring on values from future versions of git */
		free(value);
	}
	git_config(git_xmerge_config, NULL);
}
 
void init_merge_options(struct merge_options *opt,
			struct repository *repo)
{
	const char *merge_verbosity;
	memset(opt, 0, sizeof(struct merge_options));
 
	opt->repo = repo;
 
	opt->detect_renames = -1;
	opt->detect_directory_renames = MERGE_DIRECTORY_RENAMES_CONFLICT;
	opt->rename_limit = -1;
 
	opt->verbosity = 2;
	opt->buffer_output = 1;
	strbuf_init(&opt->obuf, 0);
 
	opt->renormalize = 0;
 
	merge_recursive_config(opt);
	merge_verbosity = getenv("GIT_MERGE_VERBOSITY");
	if (merge_verbosity)
		opt->verbosity = strtol(merge_verbosity, NULL, 10);
	if (opt->verbosity >= 5)
		opt->buffer_output = 0;
}
 
int parse_merge_opt(struct merge_options *opt, const char *s)
{
	const char *arg;
 
	if (!s || !*s)
		return -1;
	if (!strcmp(s, "ours"))
		opt->recursive_variant = MERGE_VARIANT_OURS;
	else if (!strcmp(s, "theirs"))
		opt->recursive_variant = MERGE_VARIANT_THEIRS;
	else if (!strcmp(s, "subtree"))
		opt->subtree_shift = "";
	else if (skip_prefix(s, "subtree=", &arg))
		opt->subtree_shift = arg;
	else if (!strcmp(s, "patience"))
		opt->xdl_opts = DIFF_WITH_ALG(opt, PATIENCE_DIFF);
	else if (!strcmp(s, "histogram"))
		opt->xdl_opts = DIFF_WITH_ALG(opt, HISTOGRAM_DIFF);
	else if (skip_prefix(s, "diff-algorithm=", &arg)) {
		long value = parse_algorithm_value(arg);
		if (value < 0)
			return -1;
		/* clear out previous settings */
		DIFF_XDL_CLR(opt, NEED_MINIMAL);
		opt->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
		opt->xdl_opts |= value;
	}
	else if (!strcmp(s, "ignore-space-change"))
		DIFF_XDL_SET(opt, IGNORE_WHITESPACE_CHANGE);
	else if (!strcmp(s, "ignore-all-space"))
		DIFF_XDL_SET(opt, IGNORE_WHITESPACE);
	else if (!strcmp(s, "ignore-space-at-eol"))
		DIFF_XDL_SET(opt, IGNORE_WHITESPACE_AT_EOL);
	else if (!strcmp(s, "ignore-cr-at-eol"))
		DIFF_XDL_SET(opt, IGNORE_CR_AT_EOL);
	else if (!strcmp(s, "renormalize"))
		opt->renormalize = 1;
	else if (!strcmp(s, "no-renormalize"))
		opt->renormalize = 0;
	else if (!strcmp(s, "no-renames"))
		opt->detect_renames = 0;
	else if (!strcmp(s, "find-renames")) {
		opt->detect_renames = 1;
		opt->rename_score = 0;
	}
	else if (skip_prefix(s, "find-renames=", &arg) ||
		 skip_prefix(s, "rename-threshold=", &arg)) {
		if ((opt->rename_score = parse_rename_score(&arg)) == -1 || *arg != 0)
			return -1;
		opt->detect_renames = 1;
	}
	/*
	 * Please update $__git_merge_strategy_options in
	 * git-completion.bash when you add new options
	 */
	else
		return -1;
	return 0;
}