Re: [PATCH v2 2/2] Avoid a segmentation fault with renaming merges

[Junio C Hamano <gitster@pobox.com>]

Junio C Hamano <gitster@pobox.com> writes:

> Looking at the commit you blamed, what happened in this case before
> that change was that
>
>  (1) make_cache_entry() would have called refresh_cache_entry() with
>      CE_MATCH_REFRESH and returned a NULL;
>
>  (2) merge-recursive.c::add_cacheinfo() noticed NULL and did
>
>      return error(_("addinfo_cache failed for path '%s'"), path)
>
> But the updated code forgot that refresh_cache_entry() could return
> NULL.  So 1335d76e45 ("merge: avoid "safer crlf" during recording of
> merge results", 2016-07-08) was not a faithful rewrite.

I'd tentatively queue the two patches fro you on top of the
jc/renormalize-merge-kill-safer-crlf topic that ends at 1335d76e45
("merge: avoid "safer crlf" during recording of merge results",
2016-07-08).  The real "fix" became like this with the above
analysis.  Semantic adjustment "error(" -> "err(o," between the old
codebase and the current one will be handled when merging.

Thanks for catching my incorrect refactoring.

-- >8 --
From: Johannes Schindelin <johannes.schindelin@gmx.de>
Date: Sat, 26 Nov 2016 13:48:06 +0100
Subject: [PATCH] merge-recursive: handle NULL in add_cacheinfo() correctly

1335d76e45 ("merge: avoid "safer crlf" during recording of merge
results", 2016-07-08) tried to split make_cache_entry() call made
with CE_MATCH_REFRESH into a call to make_cache_entry() without one,
followed by a call to add_cache_entry(), refresh_cache() and another
add_cache_entry() as needed.  However the conversion was botched in
that it forgot that refresh_cache() can return NULL, which was handled
correctly in make_cache_entry() but not in the updated code.

This fixes https://github.com/git-for-windows/git/issues/952

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 merge-recursive.c             | 2 ++
 t/t3501-revert-cherry-pick.sh | 2 +-
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/merge-recursive.c b/merge-recursive.c
index de37e5153c..56385d4c01 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -213,6 +213,8 @@ static int add_cacheinfo(unsigned int mode, const unsigned char *sha1,
 		struct cache_entry *nce;
 
 		nce = refresh_cache_entry(ce, CE_MATCH_REFRESH | CE_MATCH_IGNORE_MISSING);
+		if (!nce)
+			return error(_("addinfo_cache failed for path '%s'"), path);
 		if (nce != ce)
 			ret = add_cache_entry(nce, options);
 	}
diff --git a/t/t3501-revert-cherry-pick.sh b/t/t3501-revert-cherry-pick.sh
index 5bef564ff1..22970d2223 100755
--- a/t/t3501-revert-cherry-pick.sh
+++ b/t/t3501-revert-cherry-pick.sh
@@ -141,7 +141,7 @@ test_expect_success 'cherry-pick "-" works with arguments' '
 	test_cmp expect actual
 '
 
-test_expect_failure 'cherry-pick works with dirty renamed file' '
+test_expect_success 'cherry-pick works with dirty renamed file' '
 	test_commit to-rename &&
 	git checkout -b unrelated &&
 	test_commit unrelated &&
-- 
2.11.0-rc3-172-gc8d0e450d3