summaryrefslogtreecommitdiff
path: root/git-merge.sh
blob: 498c938c4507ccdc27f5a9e30e85f013a067c876 (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
#!/bin/sh
#
# Copyright (c) 2005 Junio C Hamano
#
 
USAGE='[-n] [--no-commit] [--squash] [-s <strategy>] [-m=<merge-message>] <commit>+'
 
SUBDIRECTORY_OK=Yes
. git-sh-setup
require_work_tree
cd_to_toplevel
 
test -z "$(git ls-files -u)" ||
	die "You are in the middle of a conflicted merge."
 
LF='
'
 
all_strategies='recur recursive octopus resolve stupid ours'
default_twohead_strategies='recursive'
default_octopus_strategies='octopus'
no_trivial_merge_strategies='ours'
use_strategies=
 
index_merge=t
 
dropsave() {
	rm -f -- "$GIT_DIR/MERGE_HEAD" "$GIT_DIR/MERGE_MSG" \
		 "$GIT_DIR/MERGE_SAVE" || exit 1
}
 
savestate() {
	# Stash away any local modifications.
	git-diff-index -z --name-only $head |
	cpio -0 -o >"$GIT_DIR/MERGE_SAVE"
}
 
restorestate() {
        if test -f "$GIT_DIR/MERGE_SAVE"
	then
		git reset --hard $head >/dev/null
		cpio -iuv <"$GIT_DIR/MERGE_SAVE"
		git-update-index --refresh >/dev/null
	fi
}
 
finish_up_to_date () {
	case "$squash" in
	t)
		echo "$1 (nothing to squash)" ;;
	'')
		echo "$1" ;;
	esac
	dropsave
}
 
squash_message () {
	echo Squashed commit of the following:
	echo
	git-log --no-merges ^"$head" $remote
}
 
finish () {
	if test '' = "$2"
	then
		rlogm="$GIT_REFLOG_ACTION"
	else
		echo "$2"
		rlogm="$GIT_REFLOG_ACTION: $2"
	fi
	case "$squash" in
	t)
		echo "Squash commit -- not updating HEAD"
		squash_message >"$GIT_DIR/SQUASH_MSG"
		;;
	'')
		case "$merge_msg" in
		'')
			echo "No merge message -- not updating HEAD"
			;;
		*)
			git-update-ref -m "$rlogm" HEAD "$1" "$head" || exit 1
			;;
		esac
		;;
	esac
	case "$1" in
	'')
		;;
	?*)
		case "$no_summary" in
		'')
			git-diff-tree --stat --summary -M "$head" "$1"
			;;
		esac
		;;
	esac
}
 
merge_name () {
	remote="$1"
	rh=$(git-rev-parse --verify "$remote^0" 2>/dev/null) || return
	bh=$(git-show-ref -s --verify "refs/heads/$remote" 2>/dev/null)
	if test "$rh" = "$bh"
	then
		echo "$rh		branch '$remote' of ."
	elif truname=$(expr "$remote" : '\(.*\)~[1-9][0-9]*$') &&
		git-show-ref -q --verify "refs/heads/$truname" 2>/dev/null
	then
		echo "$rh		branch '$truname' (early part) of ."
	else
		echo "$rh		commit '$remote'"
	fi
}
 
case "$#" in 0) usage ;; esac
 
have_message=
while case "$#" in 0) break ;; esac
do
	case "$1" in
	-n|--n|--no|--no-|--no-s|--no-su|--no-sum|--no-summ|\
		--no-summa|--no-summar|--no-summary)
		no_summary=t ;;
	--sq|--squ|--squa|--squas|--squash)
		squash=t no_commit=t ;;
	--no-c|--no-co|--no-com|--no-comm|--no-commi|--no-commit)
		no_commit=t ;;
	-s=*|--s=*|--st=*|--str=*|--stra=*|--strat=*|--strate=*|\
		--strateg=*|--strategy=*|\
	-s|--s|--st|--str|--stra|--strat|--strate|--strateg|--strategy)
		case "$#,$1" in
		*,*=*)
			strategy=`expr "z$1" : 'z-[^=]*=\(.*\)'` ;;
		1,*)
			usage ;;
		*)
			strategy="$2"
			shift ;;
		esac
		case " $all_strategies " in
		*" $strategy "*)
			use_strategies="$use_strategies$strategy " ;;
		*)
			die "available strategies are: $all_strategies" ;;
		esac
		;;
	-m=*|--m=*|--me=*|--mes=*|--mess=*|--messa=*|--messag=*|--message=*)
		merge_msg=`expr "z$1" : 'z-[^=]*=\(.*\)'`
		have_message=t
		;;
	-m|--m|--me|--mes|--mess|--messa|--messag|--message)
		shift
		case "$#" in
		1)	usage ;;
		esac
		merge_msg="$1"
		have_message=t
		;;
	-*)	usage ;;
	*)	break ;;
	esac
	shift
done
 
# This could be traditional "merge <msg> HEAD <commit>..."  and the
# way we can tell it is to see if the second token is HEAD, but some
# people might have misused the interface and used a committish that
# is the same as HEAD there instead.  Traditional format never would
# have "-m" so it is an additional safety measure to check for it.
 
if test -z "$have_message" &&
	second_token=$(git-rev-parse --verify "$2^0" 2>/dev/null) &&
	head_commit=$(git-rev-parse --verify "HEAD" 2>/dev/null) &&
	test "$second_token" = "$head_commit"
then
	merge_msg="$1"
	shift
	head_arg="$1"
	shift
elif ! git-rev-parse --verify HEAD >/dev/null 2>&1
then
	# If the merged head is a valid one there is no reason to
	# forbid "git merge" into a branch yet to be born.  We do
	# the same for "git pull".
	if test 1 -ne $#
	then
		echo >&2 "Can merge only exactly one commit into empty head"
		exit 1
	fi
 
	rh=$(git rev-parse --verify "$1^0") ||
		die "$1 - not something we can merge"
 
	git-update-ref -m "initial pull" HEAD "$rh" "" &&
	git-read-tree --reset -u HEAD
	exit
 
else
	# We are invoked directly as the first-class UI.
	head_arg=HEAD
 
	# All the rest are the commits being merged; prepare
	# the standard merge summary message to be appended to
	# the given message.  If remote is invalid we will die
	# later in the common codepath so we discard the error
	# in this loop.
	merge_name=$(for remote
		do
			merge_name "$remote"
		done | git-fmt-merge-msg
	)
	merge_msg="${merge_msg:+$merge_msg$LF$LF}$merge_name"
fi
head=$(git-rev-parse --verify "$head_arg"^0) || usage
 
# All the rest are remote heads
test "$#" = 0 && usage ;# we need at least one remote head.
set_reflog_action "merge $*"
 
remoteheads=
for remote
do
	remotehead=$(git-rev-parse --verify "$remote"^0 2>/dev/null) ||
	    die "$remote - not something we can merge"
	remoteheads="${remoteheads}$remotehead "
	eval GITHEAD_$remotehead='"$remote"'
	export GITHEAD_$remotehead
done
set x $remoteheads ; shift
 
case "$use_strategies" in
'')
	case "$#" in
	1)
		var="`git-config --get pull.twohead`"
		if test -n "$var"
		then
			use_strategies="$var"
		else
			use_strategies="$default_twohead_strategies"
		fi ;;
	*)
		var="`git-config --get pull.octopus`"
		if test -n "$var"
		then
			use_strategies="$var"
		else
			use_strategies="$default_octopus_strategies"
		fi ;;
	esac
	;;
esac
 
for s in $use_strategies
do
	for nt in $no_trivial_merge_strategies
	do
		case " $s " in
		*" $nt "*)
			index_merge=f
			break
			;;
		esac
	done
done
 
case "$#" in
1)
	common=$(git-merge-base --all $head "$@")
	;;
*)
	common=$(git-show-branch --merge-base $head "$@")
	;;
esac
echo "$head" >"$GIT_DIR/ORIG_HEAD"
 
case "$index_merge,$#,$common,$no_commit" in
f,*)
	# We've been told not to try anything clever.  Skip to real merge.
	;;
?,*,'',*)
	# No common ancestors found. We need a real merge.
	;;
?,1,"$1",*)
	# If head can reach all the merge then we are up to date.
	# but first the most common case of merging one remote.
	finish_up_to_date "Already up-to-date."
	exit 0
	;;
?,1,"$head",*)
	# Again the most common case of merging one remote.
	echo "Updating $(git-rev-parse --short $head)..$(git-rev-parse --short $1)"
	git-update-index --refresh 2>/dev/null
	new_head=$(git-rev-parse --verify "$1^0") &&
	git-read-tree -v -m -u --exclude-per-directory=.gitignore $head "$new_head" &&
	finish "$new_head" "Fast forward"
	dropsave
	exit 0
	;;
?,1,?*"$LF"?*,*)
	# We are not doing octopus and not fast forward.  Need a
	# real merge.
	;;
?,1,*,)
	# We are not doing octopus, not fast forward, and have only
	# one common.
	git-update-index --refresh 2>/dev/null
	case " $use_strategies " in
	*' recursive '*|*' recur '*)
		: run merge later
		;;
	*)
		# See if it is really trivial.
		git var GIT_COMMITTER_IDENT >/dev/null || exit
		echo "Trying really trivial in-index merge..."
		if git-read-tree --trivial -m -u -v $common $head "$1" &&
		   result_tree=$(git-write-tree)
		then
			echo "Wonderful."
			result_commit=$(
				echo "$merge_msg" |
				git-commit-tree $result_tree -p HEAD -p "$1"
			) || exit
			finish "$result_commit" "In-index merge"
			dropsave
			exit 0
		fi
		echo "Nope."
	esac
	;;
*)
	# An octopus.  If we can reach all the remote we are up to date.
	up_to_date=t
	for remote
	do
		common_one=$(git-merge-base --all $head $remote)
		if test "$common_one" != "$remote"
		then
			up_to_date=f
			break
		fi
	done
	if test "$up_to_date" = t
	then
		finish_up_to_date "Already up-to-date. Yeeah!"
		exit 0
	fi
	;;
esac
 
# We are going to make a new commit.
git var GIT_COMMITTER_IDENT >/dev/null || exit
 
# At this point, we need a real merge.  No matter what strategy
# we use, it would operate on the index, possibly affecting the
# working tree, and when resolved cleanly, have the desired tree
# in the index -- this means that the index must be in sync with
# the $head commit.  The strategies are responsible to ensure this.
 
case "$use_strategies" in
?*' '?*)
    # Stash away the local changes so that we can try more than one.
    savestate
    single_strategy=no
    ;;
*)
    rm -f "$GIT_DIR/MERGE_SAVE"
    single_strategy=yes
    ;;
esac
 
result_tree= best_cnt=-1 best_strategy= wt_strategy=
merge_was_ok=
for strategy in $use_strategies
do
    test "$wt_strategy" = '' || {
	echo "Rewinding the tree to pristine..."
	restorestate
    }
    case "$single_strategy" in
    no)
	echo "Trying merge strategy $strategy..."
	;;
    esac
 
    # Remember which strategy left the state in the working tree
    wt_strategy=$strategy
 
    git-merge-$strategy $common -- "$head_arg" "$@"
    exit=$?
    if test "$no_commit" = t && test "$exit" = 0
    then
        merge_was_ok=t
	exit=1 ;# pretend it left conflicts.
    fi
 
    test "$exit" = 0 || {
 
	# The backend exits with 1 when conflicts are left to be resolved,
	# with 2 when it does not handle the given merge at all.
 
	if test "$exit" -eq 1
	then
	    cnt=`{
		git-diff-files --name-only
		git-ls-files --unmerged
	    } | wc -l`
	    if test $best_cnt -le 0 -o $cnt -le $best_cnt
	    then
		best_strategy=$strategy
		best_cnt=$cnt
	    fi
	fi
	continue
    }
 
    # Automerge succeeded.
    result_tree=$(git-write-tree) && break
done
 
# If we have a resulting tree, that means the strategy module
# auto resolved the merge cleanly.
if test '' != "$result_tree"
then
    parents=$(git-show-branch --independent "$head" "$@" | sed -e 's/^/-p /')
    result_commit=$(echo "$merge_msg" | git-commit-tree $result_tree $parents) || exit
    finish "$result_commit" "Merge made by $wt_strategy."
    dropsave
    exit 0
fi
 
# Pick the result from the best strategy and have the user fix it up.
case "$best_strategy" in
'')
	restorestate
	case "$use_strategies" in
	?*' '?*)
		echo >&2 "No merge strategy handled the merge."
		;;
	*)
		echo >&2 "Merge with strategy $use_strategies failed."
		;;
	esac
	exit 2
	;;
"$wt_strategy")
	# We already have its result in the working tree.
	;;
*)
	echo "Rewinding the tree to pristine..."
	restorestate
	echo "Using the $best_strategy to prepare resolving by hand."
	git-merge-$best_strategy $common -- "$head_arg" "$@"
	;;
esac
 
if test "$squash" = t
then
	finish
else
	for remote
	do
		echo $remote
	done >"$GIT_DIR/MERGE_HEAD"
	echo "$merge_msg" >"$GIT_DIR/MERGE_MSG"
fi
 
if test "$merge_was_ok" = t
then
	echo >&2 \
	"Automatic merge went well; stopped before committing as requested"
	exit 0
else
	{
	    echo '
Conflicts:
'
		git ls-files --unmerged |
		sed -e 's/^[^	]*	/	/' |
		uniq
	} >>"$GIT_DIR/MERGE_MSG"
	if test -d "$GIT_DIR/rr-cache"
	then
		git-rerere
	fi
	die "Automatic merge failed; fix conflicts and then commit the result."
fi