builtin/difftool: plug several trivial memory leaks

There are several leaking data structures in git-difftool(1). Plug them.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: pks-t

builtin/difftool.c

@@ -660,6 +660,12 @@ static int run_dir_diff(const char *extcmd, int symlinks, const char *prefix,
 	if (fp)
 		fclose(fp);
 
+	hashmap_clear_and_free(&working_tree_dups, struct working_tree_entry, entry);
+	hashmap_clear_and_free(&wt_modified, struct path_entry, entry);
+	hashmap_clear_and_free(&tmp_modified, struct path_entry, entry);
+	hashmap_clear_and_free(&submodules, struct pair_entry, entry);
+	hashmap_clear_and_free(&symlinks2, struct pair_entry, entry);
+	release_index(&wtindex);
 	free(lbase_dir);
 	free(rbase_dir);
 	strbuf_release(&info);

t/t7800-difftool.sh

@@ -11,6 +11,7 @@ Testing basic diff tool invocation
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 difftool_test_setup ()