fix segfault with git log -c --follow

In diff_tree_combined we make a copy of diffopts. In
try_to_follow_renames, called via diff_tree_sha1, we free and
re-initialize diffopts->pathspec->items. Since we did not make a deep
copy of diffopts in diff_tree_combined, the original diffopts does not
get the update. By the time we return from diff_tree_combined,
rev->diffopt->pathspec->items points to an invalid memory address. We
get a segfault next time we try to access that pathspec.

Instead, along with the copy of diffopts, make a copy pathspec->items as
well.

We would also have to make a copy of pathspec->raw to keep it consistent
with pathspec->items, but nobody seems to rely on that.

Signed-off-by: Clemens Buchacher <drizzd@aon.at>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 14 insertions, 0 deletions

diff --git a/t/t4202-log.sh b/t/t4202-log.sh
index fa686b8..d9e587a 100755
--- a/t/t4202-log.sh
+++ b/t/t4202-log.sh
@@ -542,6 +542,20 @@ test_expect_success 'show added path under "--follow -M"' '
 	)
 '
 
+test_expect_success 'git log -c --follow' '
+	test_create_repo follow-c &&
+	(
+		cd follow-c &&
+		test_commit initial file original &&
+		git rm file &&
+		test_commit rename file2 original &&
+		git reset --hard initial &&
+		test_commit modify file foo &&
+		git merge -m merge rename &&
+		git log -c --follow file2
+	)
+'
+
 cat >expect <<\EOF
 *   commit COMMIT_OBJECT_NAME
 |\  Merge: MERGE_PARENTS