Regression test for gitgitgadget#1577

Signed-off-by: Kevin Backhouse <kevinbackhouse@github.com>

t/t9904-merge-leak.sh

@@ -0,0 +1,39 @@
+#!/bin/sh
+#
+
+test_description='regression test for memory leak in git merge'
+
+GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
+export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
+
+. ./lib-bash.sh
+
+# test-lib.sh disables LeakSanitizer by default, but we want it enabled
+# for this test
+export ASAN_OPTIONS=
+
+. "$GIT_BUILD_DIR/contrib/completion/git-prompt.sh"
+
+test_expect_success 'Merge fails due to local changes' '
+	git init &&
+	echo x > x.txt &&
+	git add . &&
+	git commit -m "WIP" &&
+	git checkout -b dev &&
+	echo y > x.txt &&
+	git add . &&
+	git commit -m "WIP" &&
+	git checkout main &&
+	echo z > x.txt &&
+	git add . &&
+	git commit -m "WIP" &&
+	echo a > x.txt &&
+	git add . &&
+	(echo "error: ''Your local changes to the following files would be overwritten by merge:''" >expected &&
+	echo "  x.txt" >>expected &&
+	echo "Merge with strategy ort failed." >>expected &&
+	(git merge dev 2>actual || echo "merge error is expected") &&
+	test_cmp expected actual)
+'
+
+test_done