git/t/t7605-merge-resolve.sh
Elijah Newren 40d71940b6 builtin/merge.c: fix a bug with trivial merges
If read_tree_trivial() succeeds and produces a tree that is already
in the object store, then the index is not written to disk, leaving
it out-of-sync with both HEAD and the working tree.

In order to write the index back out to disk after a merge,
write_index_locked() needs to be called.  For most merge strategies, this
is done from try_merge_strategy().  For fast forward updates, this is
done from checkout_fast_forward().  When trivial merges work, the call to
write_index_locked() is buried a little deeper:

  merge_trivial()
  -> write_tree_trivial()
     -> write_cache_as_tree()
        -> write_index_as_tree()
           -> write_locked_index()

However, it is only called when !cache_tree_fully_valid(), which is how
this bug is triggered.  But that also shows why this bug doesn't affect
any other merge strategies or cases.

Add a direct call to write_index_locked() from merge_trivial() to fix
this issue.  Since the indirect call to write_locked_index() was
conditional on cache_tree_fully_valid(), it won't be written twice.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-04-12 18:33:59 -07:00

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Executable File

#!/bin/sh
test_description='git merge
Testing the resolve strategy.'
. ./test-lib.sh
test_expect_success 'setup' '
echo c0 > c0.c &&
git add c0.c &&
git commit -m c0 &&
git tag c0 &&
echo c1 > c1.c &&
git add c1.c &&
git commit -m c1 &&
git tag c1 &&
git reset --hard c0 &&
echo c2 > c2.c &&
git add c2.c &&
git commit -m c2 &&
git tag c2 &&
git reset --hard c0 &&
echo c3 > c2.c &&
git add c2.c &&
git commit -m c3 &&
git tag c3
'
merge_c1_to_c2_cmds='
git reset --hard c1 &&
git merge -s resolve c2 &&
test "$(git rev-parse c1)" != "$(git rev-parse HEAD)" &&
test "$(git rev-parse c1)" = "$(git rev-parse HEAD^1)" &&
test "$(git rev-parse c2)" = "$(git rev-parse HEAD^2)" &&
git diff --exit-code &&
test -f c0.c &&
test -f c1.c &&
test -f c2.c &&
test 3 = $(git ls-tree -r HEAD | wc -l) &&
test 3 = $(git ls-files | wc -l)
'
test_expect_success 'merge c1 to c2' "$merge_c1_to_c2_cmds"
test_expect_success 'merge c1 to c2, again' "$merge_c1_to_c2_cmds"
test_expect_success 'merge c2 to c3 (fails)' '
git reset --hard c2 &&
test_must_fail git merge -s resolve c3
'
test_done