@matheusbsbs / matheus-bagliano / commits / 65170c07d4

merge-recursive: avoid incorporating uncommitted changes in a merge

builtin/merge.c contains this important requirement for merge strategies: /* * 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. */ merge-recursive does not do this check directly, instead it relies on unpack_trees() to do it. However, merge_trees() has a special check for the merge branch exactly matching the merge base; when it detects that situation, it returns early without calling unpack_trees(), because it knows that the HEAD commit already has the correct result. Unfortunately, it didn't check that the index matched HEAD, so after it returned, the outer logic ended up creating a merge commit that included something other than HEAD. Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Elijah Newren committed Dec 21, 2017 at 11:19 UTC 65170c07d466b18364e0d2b6a360900c073b600f

2 files changed +8 -1

merge-recursive.c

@@ -1952,6 +1952,13 @@ int merge_trees(struct merge_options *o,

1952 }

1953

1954 if (oid_eq(&common->object.oid, &merge->object.oid)) {

1955 + struct strbuf sb = STRBUF_INIT;

1956 +

1957 + if (index_has_changes(&sb)) {

1958 + err(o, _("Dirty index: cannot merge (dirty: %s)"),

1959 + sb.buf);

1960 + return 0;

1961 + }

1962 output(o, 0, _("Already up to date!"));

1963 *result = head;

1964 return 1;

t/t6044-merge-unrelated-index-changes.sh

+1 -1

@@ -112,7 +112,7 @@ test_expect_success 'recursive' '

112 test_must_fail git merge -s recursive C^0

113 '

114

115 -test_expect_failure 'recursive, when merge branch matches merge base' '

115 +test_expect_success 'recursive, when merge branch matches merge base' '

116 git reset --hard &&

117 git checkout B^0 &&

118