git-submodule: provide easy way of adding new submodules

To make a submodule effectively usable, the path and
a URL where the submodule can be cloned need to be stored
in .gitmodules.  This subcommand takes care of setting
this information after cloning the new submodule.
Only the index is updated, so, if needed, the user may still
change the URL or switch to a different branch of the submodule
before committing.

Signed-off-by: Sven Verdoolaege <skimo@kotnet.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 96 insertions, 6 deletions

diff --git a/git-submodule.sh b/git-submodule.sh
index 89a3885350..67c78f2d3d 100755
--- a/git-submodule.sh
+++ b/git-submodule.sh
@@ -1,13 +1,15 @@
 #!/bin/sh
 #
-# git-submodules.sh: init, update or list git submodules
+# git-submodules.sh: add, init, update or list git submodules
 #
 # Copyright (c) 2007 Lars Hjemli
 
-USAGE='[--quiet] [--cached] [status|init|update] [--] [<path>...]'
+USAGE='[--quiet] [--cached] [add <repo> [-b branch]|status|init|update] [--] [<path>...]'
 . git-sh-setup
 require_work_tree
 
+add=
+branch=
 init=
 update=
 status=
@@ -25,6 +27,18 @@ say()
 	fi
 }
 
+# NEEDSWORK: identical function exists in get_repo_base in clone.sh
+get_repo_base() {
+	(
+		cd "`/bin/pwd`" &&
+		cd "$1" || cd "$1.git" &&
+		{
+			cd .git
+			pwd
+		}
+	) 2>/dev/null
+}
+
 #
 # Map submodule path to submodule name
 #
@@ -42,6 +56,11 @@ module_name()
 #
 # Clone a submodule
 #
+# Prior to calling, modules_update checks that a possibly existing
+# path is not a git repository.
+# Likewise, module_add checks that path does not exist at all,
+# since it is the location of a new submodule.
+#
 module_clone()
 {
 	path=$1
@@ -66,6 +85,53 @@ module_clone()
 }
 
 #
+# Add a new submodule to the working tree, .gitmodules and the index
+#
+# $@ = repo [path]
+#
+# optional branch is stored in global branch variable
+#
+module_add()
+{
+	repo=$1
+	path=$2
+
+	if test -z "$repo"; then
+		usage
+	fi
+
+	# Turn the source into an absolute path if
+	# it is local
+	if base=$(get_repo_base "$repo"); then
+		repo="$base"
+	fi
+
+	# Guess path from repo if not specified or strip trailing slashes
+	if test -z "$path"; then
+		path=$(echo "$repo" | sed -e 's|/*$||' -e 's|:*/*\.git$||' -e 's|.*[/:]||g')
+	else
+		path=$(echo "$path" | sed -e 's|/*$||')
+	fi
+
+	test -e "$path" &&
+	die "'$path' already exists"
+
+	git-ls-files --error-unmatch "$path" > /dev/null 2>&1 &&
+	die "'$path' already exists in the index"
+
+	module_clone "$path" "$repo" || exit
+	(unset GIT_DIR && cd "$path" && git checkout -q ${branch:+-b "$branch" "origin/$branch"}) ||
+	die "Unable to checkout submodule '$path'"
+	git add "$path" ||
+	die "Failed to add submodule '$path'"
+
+	GIT_CONFIG=.gitmodules git config submodule."$path".path "$path" &&
+	GIT_CONFIG=.gitmodules git config submodule."$path".url "$repo" &&
+	git add .gitmodules ||
+	die "Failed to register submodule '$path'"
+}
+
+#
 # Register submodules in .git/config
 #
 # $@ = requested paths (default to all)
@@ -173,6 +239,9 @@ modules_list()
 while case "$#" in 0) break ;; esac
 do
 	case "$1" in
+	add)
+		add=1
+		;;
 	init)
 		init=1
 		;;
@@ -185,6 +254,14 @@ do
 	-q|--quiet)
 		quiet=1
 		;;
+	-b|--branch)
+		case "$2" in
+		'')
+			usage
+			;;
+		esac
+		branch="$2"; shift
+		;;
 	--cached)
 		cached=1
 		;;
@@ -201,14 +278,27 @@ do
 	shift
 done
 
-case "$init,$update,$status,$cached" in
-1,,,)
+case "$add,$branch" in
+1,*)
+	;;
+,)
+	;;
+,*)
+	usage
+	;;
+esac
+
+case "$add,$init,$update,$status,$cached" in
+1,,,,)
+	module_add "$@"
+	;;
+,1,,,)
 	modules_init "$@"
 	;;
-,1,,)
+,,1,,)
 	modules_update "$@"
 	;;
-,,*,*)
+,,,1,*)
 	modules_list "$@"
 	;;
 *)