Subject: Re: [PATCH] revision: fix memory leak in prepare_show_merge()

From: Junio C Hamano <[email-masked]>
Date: Thu, 05 Jun 2025 13:56:38 -0700

Patrick Steinhardt <[email-masked]> writes:

> On Wed, Jun 04, 2025 at 03:08:56AM +0000, Lidong Yan via GitGitGadget wrote:
>> From: Lidong Yan <[email-masked]>
>> 
>> In revision.c:prepare_show_merge(), we allocated an array in prune
>> but forget to free it. Since parse_pathspec is not responsible to
>> free prune, we should add `free(prune)` in the end of prepare_show_merge().
>
> That is a rather obvious memory leak indeed. Do you know why we never
> detected the leak in our CI? Is this code path not exercised at all by
> our tests?

I think we have no "show --merge" test.  Something like this may be
minimally sufficient.

 t/t7007-show.sh | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git c/t/t7007-show.sh w/t/t7007-show.sh
index d6cc69e0f2..99f4d0b963 100755
--- c/t/t7007-show.sh
+++ w/t/t7007-show.sh
@@ -167,4 +167,19 @@ test_expect_success 'show --graph is forbidden' '
   test_must_fail git show --graph HEAD
 '
 
+test_expect_success 'unmerged index' '
+	git reset --hard &&
+	git commit --allow-empty -m initial &&
+	git rev-parse HEAD >.git/MERGE_HEAD &&
+	blob1=$(echo hello | git hash-object -w --stdin) &&
+	blob2=$(echo goodbye | git hash-object -w --stdin) &&
+	blob3=$(echo world | git hash-object -w --stdin) &&
+	git update-index --add --index-info <<-EOF &&
+	100644 $blob1 1	conflicting
+	100644 $blob2 2	conflicting
+	100755 $blob3 3	conflicting
+	EOF
+	git show --merge HEAD
+'
+
 test_done