Merge branch 'jk/submodule-c-credential' into js/http-custom-headers

* jk/submodule-c-credential:
  submodule: stop sanitizing config options
  submodule: use prepare_submodule_repo_env consistently
  submodule--helper: move config-sanitizing to submodule.c
  submodule: export sanitized GIT_CONFIG_PARAMETERS
  t5550: break submodule config test into multiple sub-tests
  t5550: fix typo in $HTTPD_URL
  git_config_push_parameter: handle empty GIT_CONFIG_PARAMETERS
  git: submodule honor -c credential.* from command line
  quote: implement sq_quotef()
  submodule: fix segmentation fault in submodule--helper clone
  submodule: fix submodule--helper clone usage
  submodule: check argc count for git submodule--helper clone
  submodule: don't pass empty string arguments to submodule--helper clone

Signed-off-by: Johannes Schindelin <[email protected]>

Author: dscho

builtin/submodule--helper.c

@@ -515,6 +515,10 @@ static int module_clone(int argc, const char **argv, const char *prefix)
 		usage_with_options(git_submodule_helper_usage,
 				   module_clone_options);
 
+	if (argc || !url)
+		usage_with_options(git_submodule_helper_usage,
+				   module_clone_options);
+
 	strbuf_addf(&sb, "%s/modules/%s", get_git_dir(), name);
 	sm_gitdir = xstrdup(absolute_path(sb.buf));
 	strbuf_reset(&sb);