[PATCH v2] submodule: port subcommand 'set-url' from shell to C

[Shourya Shukla <shouryashukla.oo@gmail.com>]

This aims to convert submodule subcommand 'set-url' to a builtin.
'set-url' is ported to 'submodule--helper.c' and the latter is called
via 'git-submodule.sh'.

'module_set_url()' accepts the the user input, which is parsed by
'parse_options()', followed by the setting of the appropriate entry
(i.e., the submodule URL here). Finally, the URL is synced, via
'sync_submodule()', with the upstream.

Signed-off-by: Shourya Shukla <shouryashukla.oo@gmail.com>
---
I finally fixed the implementation, was making a silly mistake.
The test './t7420-submodule-set-url.sh' passes (both tests 1 and 2
are successful now). I have deleted the function,
'update_url_in_gitmodules()' because I was able to suffice that
functionality in the 'module_set_url()' function itself.

Thank you so much Christian and Denton for helping me :)

 builtin/submodule--helper.c | 55 +++++++++++++++++++++++++++++++++++++
 git-submodule.sh            | 25 ++---------------
 2 files changed, 58 insertions(+), 22 deletions(-)

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index 1a4b391c88..59334d4286 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -2246,6 +2246,60 @@ static int module_config(int argc, const char **argv, const char *prefix)
 	usage_with_options(git_submodule_helper_usage, module_config_options);
 }
 
+struct set_url_cb {
+	const char *prefix;
+	unsigned int flags;
+};
+
+#define SET_URL_CB_INIT { NULL, 0 }
+
+static int module_set_url(int argc, const char **argv, const char *prefix)
+{
+	struct set_url_cb info = SET_URL_CB_INIT;
+	int quiet = 0;
+
+	const char *newurl = NULL;
+	const char *path = NULL;
+	
+	struct strbuf entry = STRBUF_INIT;
+
+	struct option module_set_url_options[] = {
+		OPT__QUIET(&quiet, N_("Suppress output for setting url of a submodule")),
+		OPT_END()
+	};
+
+	const char *const git_submodule_helper_usage[] = {
+		N_("git submodule--helper set-url [--quiet] [<path>] [<newurl>]"),
+		NULL
+	};
+
+	argc = parse_options(argc, argv, NULL, module_set_url_options,
+			     git_submodule_helper_usage, 0);
+
+	info.prefix = prefix;
+	if (quiet)
+		info.flags |= OPT_QUIET;
+
+	path = argv[0];
+	newurl = argv[1];
+
+	if(!path || !newurl){
+		usage_with_options(git_submodule_helper_usage,module_set_url_options);
+		return 1;
+	}
+
+	strbuf_addstr(&entry, "submodule.");
+	strbuf_addstr(&entry, path);
+	strbuf_addstr(&entry, ".url");
+	
+	/* Setting the new URL in .gitmodules */
+	config_set_in_gitmodules_file_gently(entry.buf, newurl);  
+	/* Syncing the updated URL */
+	sync_submodule(path, prefix, info.flags);
+
+	return 0;
+}
+
 #define SUPPORT_SUPER_PREFIX (1<<0)
 
 struct cmd_struct {
@@ -2276,6 +2330,7 @@ static struct cmd_struct commands[] = {
 	{"is-active", is_active, 0},
 	{"check-name", check_name, 0},
 	{"config", module_config, 0},
+	{"set-url", module_set_url, 0},
 };
 
 int cmd_submodule__helper(int argc, const char **argv, const char *prefix)
diff --git a/git-submodule.sh b/git-submodule.sh
index 89f915cae9..ea72d5a5f5 100755
--- a/git-submodule.sh
+++ b/git-submodule.sh
@@ -783,11 +783,13 @@ cmd_set_branch() {
 # $@ = requested path, requested url
 #
 cmd_set_url() {
+
 	while test $# -ne 0
 	do
 		case "$1" in
 		-q|--quiet)
 			GIT_QUIET=1
+			shift
 			;;
 		--)
 			shift
@@ -800,30 +802,9 @@ cmd_set_url() {
 			break
 			;;
 		esac
-		shift
 	done
 
-	if test $# -ne 2
-	then
-		usage
-	fi
-
-	# we can't use `git submodule--helper name` here because internally, it
-	# hashes the path so a trailing slash could lead to an unintentional no match
-	name="$(git submodule--helper list "$1" | cut -f2)"
-	if test -z "$name"
-	then
-		exit 1
-	fi
-
-	url="$2"
-	if test -z "$url"
-	then
-		exit 1
-	fi
-
-	git submodule--helper config submodule."$name".url "$url"
-	git submodule--helper sync ${GIT_QUIET:+--quiet} "$name"
+	git ${wt_prefix:+-C "$wt_prefix"} ${prefix:+--super-prefix "$prefix"} submodule--helper set-url ${GIT_QUIET:+--quiet} -- "$@"
 }
 
 #
-- 
2.26.2