cat-file: fix a common "struct object_context" memory leak

Fix a memory leak where "cat-file" will leak the "path" member. See
e5fba602e59 (textconv: support for cat_file, 2010-06-15) for the code
that introduced the offending get_oid_with_context() call (called
get_sha1_with_context() at the time).

As a result we can mark several tests as passing with SANITIZE=leak
using "TEST_PASSES_SANITIZE_LEAK=true".

As noted in dc944b65f1d (get_sha1_with_context: dynamically allocate
oc->path, 2017-05-19) callers must free the "path" member. That same
commit added the relevant free() to this function, but we weren't
catching cases where we'd return early.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 22 insertions, 10 deletions

diff --git a/builtin/cat-file.c b/builtin/cat-file.c
index ac0459f96b..f42782e955 100644
--- a/builtin/cat-file.c
+++ b/builtin/cat-file.c
@@ -71,6 +71,7 @@ static int stream_blob(const struct object_id *oid)
 static int cat_one_file(int opt, const char *exp_type, const char *obj_name,
 			int unknown_type)
 {
+	int ret;
 	struct object_id oid;
 	enum object_type type;
 	char *buf;
@@ -106,7 +107,8 @@ static int cat_one_file(int opt, const char *exp_type, const char *obj_name,
 		if (sb.len) {
 			printf("%s\n", sb.buf);
 			strbuf_release(&sb);
-			return 0;
+			ret = 0;
+			goto cleanup;
 		}
 		break;
 
@@ -115,7 +117,8 @@ static int cat_one_file(int opt, const char *exp_type, const char *obj_name,
 		if (oid_object_info_extended(the_repository, &oid, &oi, flags) < 0)
 			die("git cat-file: could not get object info");
 		printf("%"PRIuMAX"\n", (uintmax_t)size);
-		return 0;
+		ret = 0;
+		goto cleanup;
 
 	case 'e':
 		return !has_object_file(&oid);
@@ -123,8 +126,10 @@ static int cat_one_file(int opt, const char *exp_type, const char *obj_name,
 	case 'w':
 
 		if (filter_object(path, obj_context.mode,
-				  &oid, &buf, &size))
-			return -1;
+				  &oid, &buf, &size)) {
+			ret = -1;
+			goto cleanup;
+		}
 		break;
 
 	case 'c':
@@ -143,11 +148,14 @@ static int cat_one_file(int opt, const char *exp_type, const char *obj_name,
 			const char *ls_args[3] = { NULL };
 			ls_args[0] =  "ls-tree";
 			ls_args[1] =  obj_name;
-			return cmd_ls_tree(2, ls_args, NULL);
+			ret = cmd_ls_tree(2, ls_args, NULL);
+			goto cleanup;
 		}
 
-		if (type == OBJ_BLOB)
-			return stream_blob(&oid);
+		if (type == OBJ_BLOB) {
+			ret = stream_blob(&oid);
+			goto cleanup;
+		}
 		buf = read_object_file(&oid, &type, &size);
 		if (!buf)
 			die("Cannot read object %s", obj_name);
@@ -172,8 +180,10 @@ static int cat_one_file(int opt, const char *exp_type, const char *obj_name,
 			} else
 				oidcpy(&blob_oid, &oid);
 
-			if (oid_object_info(the_repository, &blob_oid, NULL) == OBJ_BLOB)
-				return stream_blob(&blob_oid);
+			if (oid_object_info(the_repository, &blob_oid, NULL) == OBJ_BLOB) {
+				ret = stream_blob(&blob_oid);
+				goto cleanup;
+			}
 			/*
 			 * we attempted to dereference a tag to a blob
 			 * and failed; there may be new dereference
@@ -193,9 +203,11 @@ static int cat_one_file(int opt, const char *exp_type, const char *obj_name,
 		die("git cat-file %s: bad file", obj_name);
 
 	write_or_die(1, buf, size);
+	ret = 0;
+cleanup:
 	free(buf);
 	free(obj_context.path);
-	return 0;
+	return ret;
 }
 
 struct expand_data {