bundle.c: don't leak the "args" in the "struct child_process"

Fix a leak that's been here since 7366096 (bundle API: change
"flags" to be "extra_index_pack_args", 2021-09-05). If we can't verify
the bundle, we didn't call child_process_clear() to clear the "args".

But rather than adding an additional child_process_clear() call, let's
verify the bundle before we start preparing the process we're going to
spawn. If we fail to verify, we don't need to push anything to the
child_process "args".

Helped-by: Elijah Newren <[email protected]>
Signed-off-by: Ævar Arnfjörð Bjarmason <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: avar

bundle.c

@@ -627,6 +627,10 @@ int unbundle(struct repository *r, struct bundle_header *header,
 	     enum verify_bundle_flags flags)
 {
 	struct child_process ip = CHILD_PROCESS_INIT;
+
+	if (verify_bundle(r, header, flags))
+		return -1;
+
 	strvec_pushl(&ip.args, "index-pack", "--fix-thin", "--stdin", NULL);
 
 	/* If there is a filter, then we need to create the promisor pack. */
@@ -638,8 +642,6 @@ int unbundle(struct repository *r, struct bundle_header *header,
 		strvec_clear(extra_index_pack_args);
 	}
 
-	if (verify_bundle(r, header, flags))
-		return -1;
 	ip.in = bundle_fd;
 	ip.no_stdout = 1;
 	ip.git_cmd = 1;