Add --depth to submodule update/add

Add the --depth option to the add and update commands of "git submodule",
which is then passed on to the clone command. This is useful when the
submodule(s) are huge and you're not really interested in anything but
the latest commit.

Tests are added and some indention adjustments were made to conform to the
rest of the testfile on "submodule update can handle symbolic links in pwd".

Signed-off-by: Fredrik Gustafsson <iveqy@iveqy.com>
Acked-by: Jens Lehmann <Jens.Lehmann@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-submodule.txt

@@ -10,12 +10,12 @@ SYNOPSIS
 --------
 [verse]
 'git submodule' [--quiet] add [-b <branch>] [-f|--force] [--name <name>]
-	      [--reference <repository>] [--] <repository> [<path>]
+	      [--reference <repository>] [--depth <depth>] [--] <repository> [<path>]
 'git submodule' [--quiet] status [--cached] [--recursive] [--] [<path>...]
 'git submodule' [--quiet] init [--] [<path>...]
 'git submodule' [--quiet] deinit [-f|--force] [--] <path>...
 'git submodule' [--quiet] update [--init] [--remote] [-N|--no-fetch]
-	      [-f|--force] [--rebase] [--reference <repository>]
+	      [-f|--force] [--rebase] [--reference <repository>] [--depth <depth>]
 	      [--merge] [--recursive] [--] [<path>...]
 'git submodule' [--quiet] summary [--cached|--files] [(-n|--summary-limit) <n>]
 	      [commit] [--] [<path>...]
@@ -328,6 +328,12 @@ for linkgit:git-clone[1]'s `--reference` and `--shared` options carefully.
 	only in the submodules of the current repo, but also
 	in any nested submodules inside those submodules (and so on).
 
+--depth::
+	This option is valid for add and update commands. Create a 'shallow'
+	clone with a history truncated to the specified number of revisions.
+	See linkgit:git-clone[1]
+
+
 <path>...::
 	Paths to submodule(s). When specified this will restrict the command
 	to only operate on the submodules found at the specified paths.

git-submodule.sh

@@ -32,6 +32,7 @@ nofetch=
 update=
 prefix=
 custom_name=
+depth=
 
 # The function takes at most 2 arguments. The first argument is the
 # URL that navigates to the submodule origin repo. When relative, this URL
@@ -211,6 +212,7 @@ module_clone()
 	name=$2
 	url=$3
 	reference="$4"
+	depth="$5"
 	quiet=
 	if test -n "$GIT_QUIET"
 	then
@@ -233,7 +235,7 @@ module_clone()
 		mkdir -p "$gitdir_base"
 		(
 			clear_local_git_env
-			git clone $quiet -n ${reference:+"$reference"} \
+			git clone $quiet ${depth:+"$depth"} -n ${reference:+"$reference"} \
 				--separate-git-dir "$gitdir" "$url" "$sm_path"
 		) ||
 		die "$(eval_gettext "Clone of '\$url' into submodule path '\$sm_path' failed")"
@@ -309,6 +311,14 @@ cmd_add()
 			custom_name=$2
 			shift
 			;;
+		--depth)
+			case "$2" in '') usage ;; esac
+			depth="--depth=$2"
+			shift
+			;;
+		--depth=*)
+			depth=$1
+			;;
 		--)
 			shift
 			break
@@ -405,7 +415,7 @@ Use -f if you really want to add it." >&2
 				echo "$(eval_gettext "Reactivating local git directory for submodule '\$sm_name'.")"
 			fi
 		fi
-		module_clone "$sm_path" "$sm_name" "$realrepo" "$reference" || exit
+		module_clone "$sm_path" "$sm_name" "$realrepo" "$reference" "$depth" || exit
 		(
 			clear_local_git_env
 			cd "$sm_path" &&
@@ -676,6 +686,14 @@ cmd_update()
 		--checkout)
 			update="checkout"
 			;;
+		--depth)
+			case "$2" in '') usage ;; esac
+			depth="--depth=$2"
+			shift
+			;;
+		--depth=*)
+			depth=$1
+			;;
 		--)
 			shift
 			break
@@ -735,7 +753,7 @@ Maybe you want to use 'update --init'?")"
 
 		if ! test -d "$sm_path"/.git -o -f "$sm_path"/.git
 		then
-			module_clone "$sm_path" "$name" "$url" "$reference" || exit
+			module_clone "$sm_path" "$name" "$url" "$reference" "$depth" || exit
 			cloned_modules="$cloned_modules;$name"
 			subsha1=
 		else

t/t7400-submodule-basic.sh

@@ -868,4 +868,19 @@ test_expect_success 'submodule deinit fails when submodule has a .git directory
 	test -n "$(git config --get-regexp "submodule\.example\.")"
 '
 
+test_expect_success 'submodule add clone shallow submodule' '
+	mkdir super &&
+	pwd=$(pwd)
+	(
+		cd super &&
+		git init &&
+		git submodule add --depth=1 file://"$pwd"/example2 submodule &&
+		(
+			cd submodule &&
+			test 1 = $(git log --oneline | wc -l)
+		)
+	)
+'
+
+
 test_done

t/t7406-submodule-update.sh

@@ -685,14 +685,24 @@ test_expect_success 'submodule update properly revives a moved submodule' '
 test_expect_success SYMLINKS 'submodule update can handle symbolic links in pwd' '
 	mkdir -p linked/dir &&
 	ln -s linked/dir linkto &&
-	(
-		cd linkto &&
-		git clone "$TRASH_DIRECTORY"/super_update_r2 super &&
-		(
-			cd super &&
-			git submodule update --init --recursive
-		)
+	(cd linkto &&
+	 git clone "$TRASH_DIRECTORY"/super_update_r2 super &&
+	 (cd super &&
+	  git submodule update --init --recursive
+	 )
 	)
 '
 
+test_expect_success 'submodule update clone shallow submodule' '
+	git clone cloned super3 &&
+	pwd=$(pwd)
+	(cd super3 &&
+	 sed -e "s#url = ../#url = file://$pwd/#" <.gitmodules >.gitmodules.tmp &&
+	 mv -f .gitmodules.tmp .gitmodules &&
+	 git submodule update --init --depth=3
+	 (cd submodule &&
+	  test 1 = $(git log --oneline | wc -l)
+	 )
+	)
+'
 test_done