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authorJunio C Hamano <junkio@cox.net>2005-06-11 01:36:08 (GMT)
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-06-13 03:40:20 (GMT)
commit03efa6d9a4c974c502dbad457749ad316aac9cc6 (patch)
tree2cef3d82c6d57bcee34cf6b12b471127b4158d54
parent76bc82ca0ed4a0af85b7d741c04c8191738e8395 (diff)
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[PATCH] read-tree --emu23.
This new flag causes two-way fast forward to internally use the three-way merge mechanism. This behaviour is intended to offer a better fast forward semantics when used in a dirty work tree. The new test t1005 is parallel to the existing t1001 "pure 2-way" tests, but some parts that are commented out would fail. These failures are due to three-way merge enforcing too strict index requirements for cases that could succeed. This problem will be addressed by later patches. Without even changing three-way mechanism, the --emu23 two-way fast forward already gives the user an easier-to-handle merge result when a file that "merged head" updates has local modifications. This is demonstrated as "case 16" test in t1005. Signed-off-by: Junio C Hamano <junkio@cox.net> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--read-tree.c81
-rw-r--r--t/t1005-read-tree-m-2way-emu23.sh316
2 files changed, 393 insertions, 4 deletions
diff --git a/read-tree.c b/read-tree.c
index ee7a46c..f2a8bb5 100644
--- a/read-tree.c
+++ b/read-tree.c
@@ -210,6 +210,58 @@ static int twoway_merge(struct cache_entry **src, struct cache_entry **dst)
}
/*
+ * Two-way merge emulated with three-way merge.
+ *
+ * This treats "read-tree -m H M" by transforming it internally
+ * into "read-tree -m H I+H M", where I+H is a tree that would
+ * contain the contents of the current index file, overlayed on
+ * top of H. Unlike the traditional two-way merge, this leaves
+ * the stages in the resulting index file and lets the user resolve
+ * the merge conflicts using standard tools for three-way merge.
+ *
+ * This function is just to set-up such an arrangement, and the
+ * actual merge uses threeway_merge() function.
+ */
+static void setup_emu23(void)
+{
+ /* stage0 contains I, stage1 H, stage2 M.
+ * move stage2 to stage3, and create stage2 entries
+ * by scanning stage0 and stage1 entries.
+ */
+ int i, namelen, size;
+ struct cache_entry *ce, *stage2;
+
+ for (i = 0; i < active_nr; i++) {
+ ce = active_cache[i];
+ if (ce_stage(ce) != 2)
+ continue;
+ /* hoist them up to stage 3 */
+ namelen = ce_namelen(ce);
+ ce->ce_flags = create_ce_flags(namelen, 3);
+ }
+
+ for (i = 0; i < active_nr; i++) {
+ ce = active_cache[i];
+ if (ce_stage(ce) > 1)
+ continue;
+ namelen = ce_namelen(ce);
+ size = cache_entry_size(namelen);
+ stage2 = xmalloc(size);
+ memcpy(stage2, ce, size);
+ stage2->ce_flags = create_ce_flags(namelen, 2);
+ if (add_cache_entry(stage2, ADD_CACHE_OK_TO_ADD) < 0)
+ die("cannot merge index and our head tree");
+
+ /* We are done with this name, so skip to next name */
+ while (i < active_nr &&
+ ce_namelen(active_cache[i]) == namelen &&
+ !memcmp(active_cache[i]->name, ce->name, namelen))
+ i++;
+ i--; /* compensate for the loop control */
+ }
+}
+
+/*
* One-way merge.
*
* The rule is:
@@ -315,7 +367,7 @@ static struct cache_file cache_file;
int main(int argc, char **argv)
{
- int i, newfd, merge, reset;
+ int i, newfd, merge, reset, emu23;
unsigned char sha1[20];
newfd = hold_index_file_for_update(&cache_file, get_index_file());
@@ -324,6 +376,7 @@ int main(int argc, char **argv)
merge = 0;
reset = 0;
+ emu23 = 0;
for (i = 1; i < argc; i++) {
const char *arg = argv[i];
@@ -335,7 +388,7 @@ int main(int argc, char **argv)
/* This differs from "-m" in that we'll silently ignore unmerged entries */
if (!strcmp(arg, "--reset")) {
- if (stage || merge)
+ if (stage || merge || emu23)
usage(read_tree_usage);
reset = 1;
merge = 1;
@@ -345,7 +398,7 @@ int main(int argc, char **argv)
/* "-m" stands for "merge", meaning we start in stage 1 */
if (!strcmp(arg, "-m")) {
- if (stage || merge)
+ if (stage || merge || emu23)
usage(read_tree_usage);
if (read_cache_unmerged())
die("you need to resolve your current index first");
@@ -353,6 +406,17 @@ int main(int argc, char **argv)
merge = 1;
continue;
}
+
+ /* "-emu23" uses 3-way merge logic to perform fast-forward */
+ if (!strcmp(arg, "--emu23")) {
+ if (stage || merge || emu23)
+ usage(read_tree_usage);
+ if (read_cache_unmerged())
+ die("you need to resolve your current index first");
+ merge = emu23 = stage = 1;
+ continue;
+ }
+
if (get_sha1(arg, sha1) < 0)
usage(read_tree_usage);
if (stage > 3)
@@ -369,9 +433,18 @@ int main(int argc, char **argv)
[2] = twoway_merge,
[3] = threeway_merge,
};
+ merge_fn_t fn;
+
if (stage < 2 || stage > 4)
die("just how do you expect me to merge %d trees?", stage-1);
- merge_cache(active_cache, active_nr, merge_function[stage-1]);
+ if (emu23 && stage != 3)
+ die("--emu23 takes only two trees");
+ fn = merge_function[stage-1];
+ if (stage == 3 && emu23) {
+ setup_emu23();
+ fn = merge_function[3];
+ }
+ merge_cache(active_cache, active_nr, fn);
}
if (write_cache(newfd, active_cache, active_nr) ||
commit_index_file(&cache_file))
diff --git a/t/t1005-read-tree-m-2way-emu23.sh b/t/t1005-read-tree-m-2way-emu23.sh
new file mode 100644
index 0000000..3345c9d
--- /dev/null
+++ b/t/t1005-read-tree-m-2way-emu23.sh
@@ -0,0 +1,316 @@
+#!/bin/sh
+#
+# Copyright (c) 2005 Junio C Hamano
+#
+
+test_description='Two way merge with read-tree --emu23 $H $M
+
+This test tries two-way merge (aka fast forward with carry forward).
+
+There is the head (called H) and another commit (called M), which is
+simply ahead of H. The index and the work tree contains a state that
+is derived from H, but may also have local changes. This test checks
+all the combinations described in the two-tree merge "carry forward"
+rules, found in <Documentation/git-rev-tree.txt>.
+
+In the test, these paths are used:
+ bozbar - in H, stays in M, modified from bozbar to gnusto
+ frotz - not in H added in M
+ nitfol - in H, stays in M unmodified
+ rezrov - in H, deleted in M
+ yomin - not in H nor M
+'
+. ./test-lib.sh
+
+read_tree_twoway () {
+ git-read-tree --emu23 "$1" "$2" &&
+ git-ls-files --stage &&
+ git-merge-cache git-merge-one-file-script -a &&
+ git-ls-files --stage
+}
+
+_x40='[0-9a-f][0-9a-f][0-9a-f][0-9a-f][0-9a-f]'
+_x40="$_x40$_x40$_x40$_x40$_x40$_x40$_x40$_x40"
+compare_change () {
+ cat current
+ sed -n >current \
+ -e '/^--- /d; /^+++ /d; /^@@ /d;' \
+ -e 's/^\([-+][0-7][0-7][0-7][0-7][0-7][0-7]\) '"$_x40"' /\1 X /p' \
+ "$1"
+ diff -u expected current
+}
+
+check_cache_at () {
+ clean_if_empty=`git-diff-files "$1"`
+ case "$clean_if_empty" in
+ '') echo "$1: clean" ;;
+ ?*) echo "$1: dirty" ;;
+ esac
+ case "$2,$clean_if_empty" in
+ clean,) : ;;
+ clean,?*) false ;;
+ dirty,) false ;;
+ dirty,?*) : ;;
+ esac
+}
+
+check_stages () {
+ cat >expected_stages
+ git-ls-files --stage | sed -e "s/ $_x40 / X /" >current_stages
+ diff -u expected_stages current_stages
+}
+
+test_expect_success \
+ setup \
+ 'echo frotz >frotz &&
+ echo nitfol >nitfol &&
+ echo bozbar >bozbar &&
+ echo rezrov >rezrov &&
+ echo yomin >yomin &&
+ git-update-cache --add nitfol bozbar rezrov &&
+ treeH=`git-write-tree` &&
+ echo treeH $treeH &&
+ git-ls-tree $treeH &&
+
+ echo gnusto >bozbar &&
+ git-update-cache --add frotz bozbar --force-remove rezrov &&
+ git-ls-files --stage >M.out &&
+ treeM=`git-write-tree` &&
+ echo treeM $treeM &&
+ git-ls-tree $treeM &&
+ git-diff-tree $treeH $treeM'
+
+test_expect_success \
+ '1, 2, 3 - no carry forward' \
+ 'rm -f .git/index &&
+ read_tree_twoway $treeH $treeM &&
+ git-ls-files --stage >1-3.out &&
+ diff -u M.out 1-3.out &&
+ check_cache_at bozbar dirty &&
+ check_cache_at frotz clean && # different from pure 2-way
+ check_cache_at nitfol dirty'
+
+echo '+100644 X 0 yomin' >expected
+
+test_expect_success \
+ '4 - carry forward local addition.' \
+ 'rm -f .git/index &&
+ git-update-cache --add yomin &&
+ read_tree_twoway $treeH $treeM &&
+ git-ls-files --stage >4.out || exit
+ diff -u M.out 4.out >4diff.out
+ compare_change 4diff.out expected &&
+ check_cache_at yomin clean'
+
+# "read-tree -m H I+H M" where !H && !M; so (I+H) not being up-to-date
+# should not matter, but without #3ALT this does not work.
+: test_expect_success \
+ '5 - carry forward local addition.' \
+ 'rm -f .git/index &&
+ echo yomin >yomin &&
+ git-update-cache --add yomin &&
+ echo yomin yomin >yomin &&
+ read_tree_twoway $treeH $treeM &&
+ git-ls-files --stage >5.out || exit
+ diff -u M.out 5.out >5diff.out
+ compare_change 5diff.out expected &&
+ check_cache_at yomin dirty'
+
+# "read-tree -m H I+H M" where !H && M && (I+H) == M, so this should
+# succeed (even the entry is clean), but without #5ALT this does not
+# work.
+: test_expect_success \
+ '6 - local addition already has the same.' \
+ 'rm -f .git/index &&
+ git-update-cache --add frotz &&
+ read_tree_twoway $treeH $treeM &&
+ git-ls-files --stage >6.out &&
+ diff -u M.out 6.out &&
+ check_cache_at frotz clean'
+
+# Exactly the same pattern as above but with dirty cache. This also
+# should succeed, but without #5ALT it does not.
+: test_expect_success \
+ '7 - local addition already has the same.' \
+ 'rm -f .git/index &&
+ echo frotz >frotz &&
+ git-update-cache --add frotz &&
+ echo frotz frotz >frotz &&
+ read_tree_twoway $treeH $treeM &&
+ git-ls-files --stage >7.out &&
+ diff -u M.out 7.out &&
+ check_cache_at frotz dirty'
+
+test_expect_success \
+ '8 - conflicting addition.' \
+ 'rm -f .git/index &&
+ echo frotz frotz >frotz &&
+ git-update-cache --add frotz &&
+ if read_tree_twoway $treeH $treeM; then false; else :; fi'
+
+test_expect_success \
+ '9 - conflicting addition.' \
+ 'rm -f .git/index &&
+ echo frotz frotz >frotz &&
+ git-update-cache --add frotz &&
+ echo frotz >frotz &&
+ if read_tree_twoway $treeH $treeM; then false; else :; fi'
+
+test_expect_success \
+ '10 - path removed.' \
+ 'rm -f .git/index &&
+ echo rezrov >rezrov &&
+ git-update-cache --add rezrov &&
+ read_tree_twoway $treeH $treeM &&
+ git-ls-files --stage >10.out &&
+ diff -u M.out 10.out'
+
+test_expect_success \
+ '11 - dirty path removed.' \
+ 'rm -f .git/index &&
+ echo rezrov >rezrov &&
+ git-update-cache --add rezrov &&
+ echo rezrov rezrov >rezrov &&
+ if read_tree_twoway $treeH $treeM; then false; else :; fi'
+
+test_expect_success \
+ '12 - unmatching local changes being removed.' \
+ 'rm -f .git/index &&
+ echo rezrov rezrov >rezrov &&
+ git-update-cache --add rezrov &&
+ if read_tree_twoway $treeH $treeM; then false; else :; fi'
+
+test_expect_success \
+ '13 - unmatching local changes being removed.' \
+ 'rm -f .git/index &&
+ echo rezrov rezrov >rezrov &&
+ git-update-cache --add rezrov &&
+ echo rezrov >rezrov &&
+ if read_tree_twoway $treeH $treeM; then false; else :; fi'
+
+cat >expected <<EOF
+-100644 X 0 nitfol
++100644 X 0 nitfol
+EOF
+
+test_expect_success \
+ '14 - unchanged in two heads.' \
+ 'rm -f .git/index &&
+ echo nitfol nitfol >nitfol &&
+ git-update-cache --add nitfol &&
+ read_tree_twoway $treeH $treeM &&
+ git-ls-files --stage >14.out || exit
+ diff -u M.out 14.out >14diff.out
+ compare_change 14diff.out expected &&
+ check_cache_at nitfol clean'
+
+test_expect_success \
+ '15 - unchanged in two heads.' \
+ 'rm -f .git/index &&
+ echo nitfol nitfol >nitfol &&
+ git-update-cache --add nitfol &&
+ echo nitfol nitfol nitfol >nitfol &&
+ read_tree_twoway $treeH $treeM &&
+ git-ls-files --stage >15.out || exit
+ diff -u M.out 15.out >15diff.out
+ compare_change 15diff.out expected &&
+ check_cache_at nitfol dirty'
+
+# This is different from straight 2-way merge in that it leaves
+# three stages of bozbar in the index file without failing, so
+# the user can run git-diff-stages to examine the situation.
+test_expect_success \
+ '16 - conflicting local change.' \
+ 'rm -f .git/index &&
+ echo bozbar bozbar >bozbar &&
+ git-update-cache --add bozbar &&
+ git-read-tree --emu23 $treeH $treeM &&
+ check_stages' <<\EOF
+100644 X 1 bozbar
+100644 X 2 bozbar
+100644 X 3 bozbar
+100644 X 3 frotz
+100644 X 0 nitfol
+100644 X 1 rezrov
+100644 X 2 rezrov
+EOF
+
+test_expect_success \
+ '17 - conflicting local change.' \
+ 'rm -f .git/index &&
+ echo bozbar bozbar >bozbar &&
+ git-update-cache --add bozbar &&
+ echo bozbar bozbar bozbar >bozbar &&
+ if read_tree_twoway $treeH $treeM; then false; else :; fi'
+
+test_expect_success \
+ '18 - local change already having a good result.' \
+ 'rm -f .git/index &&
+ echo gnusto >bozbar &&
+ git-update-cache --add bozbar &&
+ read_tree_twoway $treeH $treeM &&
+ git-ls-files --stage >18.out &&
+ diff -u M.out 18.out &&
+ check_cache_at bozbar clean'
+
+test_expect_success \
+ '19 - local change already having a good result, further modified.' \
+ 'rm -f .git/index &&
+ echo gnusto >bozbar &&
+ git-update-cache --add bozbar &&
+ echo gnusto gnusto >bozbar &&
+ read_tree_twoway $treeH $treeM &&
+ git-ls-files --stage >19.out &&
+ diff -u M.out 19.out &&
+ check_cache_at bozbar dirty'
+
+test_expect_success \
+ '20 - no local change, use new tree.' \
+ 'rm -f .git/index &&
+ echo bozbar >bozbar &&
+ git-update-cache --add bozbar &&
+ read_tree_twoway $treeH $treeM &&
+ git-ls-files --stage >20.out &&
+ diff -u M.out 20.out &&
+ check_cache_at bozbar dirty'
+
+test_expect_success \
+ '21 - no local change, dirty cache.' \
+ 'rm -f .git/index &&
+ echo bozbar >bozbar &&
+ git-update-cache --add bozbar &&
+ echo gnusto gnusto >bozbar &&
+ if read_tree_twoway $treeH $treeM; then false; else :; fi'
+
+# Also make sure we did not break DF vs DF/DF case.
+test_expect_success \
+ 'DF vs DF/DF case setup.' \
+ 'rm -f .git/index &&
+ echo DF >DF &&
+ git-update-cache --add DF &&
+ treeDF=`git-write-tree` &&
+ echo treeDF $treeDF &&
+ git-ls-tree $treeDF &&
+
+ rm -f DF &&
+ mkdir DF &&
+ echo DF/DF >DF/DF &&
+ git-update-cache --add --remove DF DF/DF &&
+ treeDFDF=`git-write-tree` &&
+ echo treeDFDF $treeDFDF &&
+ git-ls-tree $treeDFDF &&
+ git-ls-files --stage >DFDF.out'
+
+test_expect_success \
+ 'DF vs DF/DF case test.' \
+ 'rm -f .git/index &&
+ rm -fr DF &&
+ echo DF >DF &&
+ git-update-cache --add DF &&
+ read_tree_twoway $treeDF $treeDFDF &&
+ git-ls-files --stage >DFDFcheck.out &&
+ diff -u DFDF.out DFDFcheck.out &&
+ check_cache_at DF/DF clean && # different from pure 2-way
+ :'
+
+test_done