[PATCH] Teach git submodule update to use distributed repositories

["Nigel Magnay" <nigel.magnay@gmail.com>]

When doing a git submodule update, it fetches any missing submodule
commits from the repository specified in .gitmodules. If you instead
want to pull from another repository, you currently need to do a fetch
in each submodule by hand.

Signed-off-by: Nigel Magnay <nigel.magnay@gmail.com>
---
This is my first attempt at adding things to help everyday usage of
git submodule.

I don't usually write much shell script; and it's my first patch, so
it's possible there are better ways to do these things..

 git-submodule.sh |   33 +++++++++++++++++++++++++++++++--
 1 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/git-submodule.sh b/git-submodule.sh
index 9228f56..40e1aa1 100755
--- a/git-submodule.sh
+++ b/git-submodule.sh
@@ -5,7 +5,7 @@
 # Copyright (c) 2007 Lars Hjemli

 USAGE="[--quiet] [--cached] \
-[add <repo> [-b branch] <path>]|[status|init|update
[-i|--init]|summary [-n|--summary-limit <n>] [<commit>]] \
+[add <repo> [-b branch] <path>]|[status|init|update [-i|--init]
[-o|--origin <repository>] [-r|-refspec <refspec>]|summary
[-n|--summary-limit <n>] [<commit>]] \
 [--] [<path>...]"
 OPTIONS_SPEC=
 . git-sh-setup
@@ -15,6 +15,8 @@ command=
 branch=
 quiet=
 cached=
+repository=
+refspec=

 #
 # print stuff on stdout unless -q was specified
@@ -270,6 +272,14 @@ cmd_update()
 			shift
 			cmd_init "$@" || return
 			;;
+		-o|--origin)
+			shift
+			repository=$1
+			;;
+		-r|--refspec)
+			shift
+			refspec=$1
+			;;
 		--)
 			shift
 			break
@@ -311,7 +321,9 @@ cmd_update()

 		if test "$subsha1" != "$sha1"
 		then
-			(unset GIT_DIR; cd "$path" && git-fetch &&
+			set_submodule_repository "$repository" "$path"
+
+			(unset GIT_DIR; cd "$path" && git-fetch "$subrepo" "$refspec" &&
 				git-checkout -q "$sha1") ||
 			die "Unable to checkout '$sha1' in submodule path '$path'"

@@ -320,6 +332,23 @@ cmd_update()
 	done
 }

+#
+# If we asked for a repository such as 'origin', just pass this through
+# otherwise, try to calculate what the repository URL might be by
+# adding the submodule path to the url, subtracting any /.git first
+#
+set_submodule_repository() {
+
+	if [ -z `echo "$1" | grep '/'` ]
+	then
+		# This is not a URL - just use the name
+		subrepo="$1"
+	else
+		# This is a URL. Chop off /.git if it's there, and add submodule path
+		subrepo="${1/%\/.git/}/$2"
+	fi
+}
+
 set_name_rev () {
 	revname=$( (
 		unset GIT_DIR
-- 
1.5.6.2