Subject: [PATCH v3] revision: fix memory leak in prepare_show_merge()

From: "Lidong Yan via GitGitGadget" <[email-masked]>
Date: Tue, 10 Jun 2025 00:37:59 +0000

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().

Signed-off-by: Lidong Yan <[email-masked]>
---
    revision: fix memory leak in prepare_show_merge()
    
    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().

Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-git-1989%2Fbrandb97%2Ffix-revision-leak-v3
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-git-1989/brandb97/fix-revision-leak-v3
Pull-Request: https://github.com/git/git/pull/1989

Range-diff vs v2:

 1:  61a2d98dad9 ! 1:  88795b33bbe revision: fix memory leak in prepare_show_merge()
     @@ t/t7007-show.sh: test_expect_success 'show --graph is forbidden' '
       '
       
      +test_expect_success 'show unmerged index' '
     -+    git reset --hard &&
     ++	git reset --hard &&
      +
     -+    git switch -C base &&
     -+    echo "base" > conflicting &&
     -+    git add conflicting &&
     -+    git commit -m "base" &&
     ++	git switch -C base &&
     ++	echo "base" >conflicting &&
     ++	git add conflicting &&
     ++	git commit -m "base" &&
      +
     -+    git branch hello &&
     -+    git branch goodbye &&
     ++	git branch hello &&
     ++	git branch goodbye &&
      +
     -+    git switch hello &&
     -+    echo "hello" > conflicting &&
     -+    git commit -am "hello" &&
     ++	git switch hello &&
     ++	echo "hello" >conflicting &&
     ++	git commit -am "hello" &&
      +
     -+    git switch goodbye &&
     -+    echo "goodbye" > conflicting &&
     -+    git commit -am "goodbye" &&
     ++	git switch goodbye &&
     ++	echo "goodbye" >conflicting &&
     ++	git commit -am "goodbye" &&
      +
     -+    git switch hello &&
     -+    test_must_fail git merge goodbye &&
     -+    git show --merge HEAD
     ++	git switch hello &&
     ++	test_must_fail git merge goodbye &&
     ++	git show --merge HEAD
      +'
      +
       test_done

 revision.c      |  1 +
 t/t7007-show.sh | 24 ++++++++++++++++++++++++
 2 files changed, 25 insertions(+)

diff --git a/revision.c b/revision.c
index 2c36a9c179ef..afee11119615 100644
--- a/revision.c
+++ b/revision.c
@@ -2060,6 +2060,7 @@ static void prepare_show_merge(struct rev_info *revs)
 	parse_pathspec(&revs->prune_data, PATHSPEC_ALL_MAGIC & ~PATHSPEC_LITERAL,
 		       PATHSPEC_PREFER_FULL | PATHSPEC_LITERAL_PATH, "", prune);
 	revs->limited = 1;
+	free(prune);
 }
 
 static int dotdot_missing(const char *arg, char *dotdot,
diff --git a/t/t7007-show.sh b/t/t7007-show.sh
index d6cc69e0f2cb..2d322b53d16e 100755
--- a/t/t7007-show.sh
+++ b/t/t7007-show.sh
@@ -167,4 +167,28 @@ test_expect_success 'show --graph is forbidden' '
   test_must_fail git show --graph HEAD
 '
 
+test_expect_success 'show unmerged index' '
+	git reset --hard &&
+
+	git switch -C base &&
+	echo "base" >conflicting &&
+	git add conflicting &&
+	git commit -m "base" &&
+
+	git branch hello &&
+	git branch goodbye &&
+
+	git switch hello &&
+	echo "hello" >conflicting &&
+	git commit -am "hello" &&
+
+	git switch goodbye &&
+	echo "goodbye" >conflicting &&
+	git commit -am "goodbye" &&
+
+	git switch hello &&
+	test_must_fail git merge goodbye &&
+	git show --merge HEAD
+'
+
 test_done

base-commit: 7014b55638da979331baf8dc31c4e1d697cf2d67
-- 
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