From 7f8ab8dc07ba4e892d0c2b5e7ac8436f9e845920 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sun, 16 Mar 2008 11:42:50 -0700 Subject: [PATCH] Don't update unchanged merge entries In commit 34110cd4e394e3f92c01a4709689b384c34645d8 ("Make 'unpack_trees()' have a separate source and destination index") I introduced a really stupid bug in that it would always add merged entries with the CE_UPDATE flag set. That caused us to always re-write the file, even when it was already up-to-date in the source index. Not only is that really stupid from a performance angle, but more importantly it's actively wrong: if we have dirty state in the tree when we merge, overwriting it with the result of the merge will incorrectly overwrite that dirty state. This trivially fixes the problem - simply don't set the CE_UPDATE flag when the merge result matches the old state. Signed-off-by: Linus Torvalds Signed-off-by: Junio C Hamano --- t/t1004-read-tree-m-u-wf.sh | 41 +++++++++++++++++++++++++++++++++++++ unpack-trees.c | 9 +++++--- 2 files changed, 47 insertions(+), 3 deletions(-) diff --git a/t/t1004-read-tree-m-u-wf.sh b/t/t1004-read-tree-m-u-wf.sh index d609a551a..9d1371c2c 100755 --- a/t/t1004-read-tree-m-u-wf.sh +++ b/t/t1004-read-tree-m-u-wf.sh @@ -116,4 +116,45 @@ test_expect_success 'three-way not complaining on an untracked file' ' git read-tree -m -u --exclude-per-directory=.gitignore branch-point master side ' +test_expect_success '3-way not overwriting local changes (setup)' ' + + git reset --hard && + git checkout -b side-a branch-point && + echo >>file1 "new line to be kept in the merge result" && + git commit -a -m "side-a changes file1" && + git checkout -b side-b branch-point && + echo >>file2 "new line to be kept in the merge result" && + git commit -a -m "side-b changes file2" && + git checkout side-a + +' + +test_expect_success '3-way not overwriting local changes (our side)' ' + + # At this point, file1 from side-a should be kept as side-b + # did not touch it. + + git reset --hard && + + echo >>file1 "local changes" && + git read-tree -m -u branch-point side-a side-b && + grep "new line to be kept" file1 && + grep "local changes" file1 + +' + +test_expect_success '3-way not overwriting local changes (their side)' ' + + # At this point, file2 from side-b should be taken as side-a + # did not touch it. + + git reset --hard && + + echo >>file2 "local changes" && + test_must_fail git read-tree -m -u branch-point side-a side-b && + ! grep "new line to be kept" file2 && + grep "local changes" file2 + +' + test_done diff --git a/unpack-trees.c b/unpack-trees.c index 93019abdc..4b359e083 100644 --- a/unpack-trees.c +++ b/unpack-trees.c @@ -595,16 +595,19 @@ static int verify_absent(struct cache_entry *ce, const char *action, static int merged_entry(struct cache_entry *merge, struct cache_entry *old, struct unpack_trees_options *o) { + int update = CE_UPDATE; + if (old) { /* * See if we can re-use the old CE directly? * That way we get the uptodate stat info. * - * This also removes the UPDATE flag on - * a match. + * This also removes the UPDATE flag on a match; otherwise + * we will end up overwriting local changes in the work tree. */ if (same(old, merge)) { copy_cache_entry(merge, old); + update = 0; } else { if (verify_uptodate(old, o)) return -1; @@ -617,7 +620,7 @@ static int merged_entry(struct cache_entry *merge, struct cache_entry *old, invalidate_ce_path(merge, o); } - add_entry(o, merge, CE_UPDATE, CE_STAGEMASK); + add_entry(o, merge, update, CE_STAGEMASK); return 1; } -- 2.26.2