Phillip found out that 'git checkout -f <branch>' does not restore
conflict/unmerged files correctly. All tracked files should be taken
from <branch> and all non-zero stages removed. Most of this is true,
except that the final file could be in stage one instead of zero.
"checkout -f" (among other commands) does this with one-way merge, which
is supposed to take stat info from the index and everything else from
the given tree. The add_entry(.., old, ...) call in oneway_merge()
though will keep stage index from the index.
This is normally not a problem if the entry from the index is
normal (stage #0). But if there is a conflict, stage #0 does not exist
and we'll get stage #1 entry as "old" variable, which gets recorded in
the final index. Fix it by clearing stage mask.
This bug probably comes from b5b425074e (git-read-tree: make one-way
merge also honor the "update" flag, 2005-06-07). Before this commit, we
may create the final ("dst") index entry from the one in index, but we
do clear CE_STAGEMASK.
I briefly checked two- and three-way merge functions. I think we don't
have the same problem in those.
Reported-by: Phillip Wood <phillip.wood123@xxxxxxxxx>
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@xxxxxxxxx>
---
v2 updates log message to describe the problem and moves the test to
t2023-checkout.m.sh
t/t2023-checkout-m.sh | 24 ++++++++++++++++++++++++
unpack-trees.c | 2 +-
2 files changed, 25 insertions(+), 1 deletion(-)
diff --git a/t/t2023-checkout-m.sh b/t/t2023-checkout-m.sh
index 7e18985134..fca3f85824 100755
--- a/t/t2023-checkout-m.sh
+++ b/t/t2023-checkout-m.sh
@@ -46,4 +46,28 @@ test_expect_success '-m restores 3-way conflicted+resolved file' '
test_cmp both.txt.conflicted.cleaned both.txt.cleaned
'
+test_expect_success 'force checkout a conflict file creates stage zero entry' '
+ git init co-force &&
+ (
+ cd co-force &&
+ echo a >a &&
+ git add a &&
+ git commit -ama &&
+ A_OBJ=$(git rev-parse :a) &&
+ git branch topic &&
+ echo b >a &&
+ git commit -amb &&
+ B_OBJ=$(git rev-parse :a) &&
+ git checkout topic &&
+ echo c >a &&
+ C_OBJ=$(git hash-object a) &&
+ git checkout -m master &&
+ test_cmp_rev :1:a $A_OBJ &&
+ test_cmp_rev :2:a $B_OBJ &&
+ test_cmp_rev :3:a $C_OBJ &&
+ git checkout -f topic &&
+ test_cmp_rev :0:a $A_OBJ
+ )
+'
+
test_done
diff --git a/unpack-trees.c b/unpack-trees.c
index 22c41a3ba8..1ccd343cad 100644
--- a/unpack-trees.c
+++ b/unpack-trees.c
@@ -2386,7 +2386,7 @@ int oneway_merge(const struct cache_entry * const *src,
if (o->update && S_ISGITLINK(old->ce_mode) &&
should_update_submodules() && !verify_uptodate(old, o))
update |= CE_UPDATE;
- add_entry(o, old, update, 0);
+ add_entry(o, old, update, CE_STAGEMASK);
return 0;
}
return merged_entry(a, old, o);
--
2.21.0.548.gd3c7d92dc2
