submodule update: add `--init-default-path` switch

The new switch `--init-default-path` initializes the submodules which are
configured in `submodule.defaultUpdatePath` instead of those given as
command line arguments before updating. In the first implementation this
is made incompatible with further command line arguments as it is
unclear what the user means by

    git submodule update --init --init-default-path <paths>

This new switch allows to record more complex patterns as it saves
retyping them whenever you invoke update.

Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

4 files changed, 89 insertions, 7 deletions

diff --git a/Documentation/config.txt b/Documentation/config.txt
index 58673cf21e..04275a4a89 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -2806,6 +2806,11 @@ submodule.fetchJobs::
 	in parallel. A value of 0 will give some reasonable default.
 	If unset, it defaults to 1.
 
+submodule.defaultUpdatePath::
+	Specifies a set of submodules to initialize when calling
+	`git submodule --init-default-group` by using the pathspec
+	syntax.
+
 tag.forceSignAnnotated::
 	A boolean to specify whether annotated tags created should be GPG signed.
 	If `--annotate` is specified on the command line, it takes
diff --git a/Documentation/git-submodule.txt b/Documentation/git-submodule.txt
index bf3bb372ee..503fec8bc6 100644
--- a/Documentation/git-submodule.txt
+++ b/Documentation/git-submodule.txt
@@ -14,10 +14,10 @@ SYNOPSIS
 'git submodule' [--quiet] status [--cached] [--recursive] [--] [<path>...]
 'git submodule' [--quiet] init [--] [<path>...]
 'git submodule' [--quiet] deinit [-f|--force] (--all|[--] <path>...)
-'git submodule' [--quiet] update [--init] [--remote] [-N|--no-fetch]
-	      [--[no-]recommend-shallow] [-f|--force] [--rebase|--merge]
-	      [--reference <repository>] [--depth <depth>] [--recursive]
-	      [--jobs <n>] [--] [<path>...]
+'git submodule' [--quiet] update [--init[-default-path]] [--remote] [-N|--no-fetch]
+	      [--[no-]recommend-shallow]
+	      [-f|--force] [--rebase|--merge] [--reference <repository>]
+	      [--depth <depth>] [--recursive] [--jobs <n>] [--] [<path>...]
 'git submodule' [--quiet] summary [--cached|--files] [(-n|--summary-limit) <n>]
 	      [commit] [--] [<path>...]
 'git submodule' [--quiet] foreach [--recursive] <command>
@@ -194,6 +194,10 @@ If the submodule is not yet initialized, and you just want to use the
 setting as stored in .gitmodules, you can automatically initialize the
 submodule with the `--init` option.
 
+You can configure a set of submodules using pathspec syntax in
+submodule.defaultUpdatePath you can use `--init-default-path` to initialize
+those before updating.
+
 If `--recursive` is specified, this command will recurse into the
 registered submodules, and update any nested submodules within.
 --
@@ -361,6 +365,11 @@ the submodule itself.
 	Initialize all submodules for which "git submodule init" has not been
 	called so far before updating.
 
+--init-default-path::
+	This option is only valid for the update command.
+	Initialize all submodules configured in "`submodule.defaultUpdatePath`"
+	that have not been updated before.
+
 --name::
 	This option is only valid for the add command. It sets the submodule's
 	name to the given string instead of defaulting to its path. The name
diff --git a/git-submodule.sh b/git-submodule.sh
index b39ac106ec..4dbcf0b507 100755
--- a/git-submodule.sh
+++ b/git-submodule.sh
@@ -9,7 +9,7 @@ USAGE="[--quiet] add [-b <branch>] [-f|--force] [--name <name>] [--reference <re
    or: $dashless [--quiet] status [--cached] [--recursive] [--] [<path>...]
    or: $dashless [--quiet] init [--] [<path>...]
    or: $dashless [--quiet] deinit [-f|--force] (--all| [--] <path>...)
-   or: $dashless [--quiet] update [--init] [--remote] [-N|--no-fetch] [-f|--force] [--checkout|--merge|--rebase] [--[no-]recommend-shallow] [--reference <repository>] [--recursive] [--] [<path>...]
+   or: $dashless [--quiet] update [--init[-default-path]] [--remote] [-N|--no-fetch] [-f|--force] [--checkout|--merge|--rebase] [--[no-]recommend-shallow] [--reference <repository>] [--recursive] [--] [<path>...]
    or: $dashless [--quiet] summary [--cached|--files] [--summary-limit <n>] [commit] [--] [<path>...]
    or: $dashless [--quiet] foreach [--recursive] <command>
    or: $dashless [--quiet] sync [--recursive] [--] [<path>...]"
@@ -499,7 +499,12 @@ cmd_update()
 			GIT_QUIET=1
 			;;
 		-i|--init)
-			init=1
+			test -z $init || test $init = by_args || die "$(gettext "Only one of --init or --init-default-path may be used.")"
+			init=by_args
+			;;
+		--init-default-path)
+			test -z $init || test $init = by_config || die "$(gettext "Only one of --init or --init-default-path may be used.")"
+			init=by_config
 			;;
 		--remote)
 			remote=1
@@ -568,7 +573,17 @@ cmd_update()
 
 	if test -n "$init"
 	then
-		cmd_init "--" "$@" || return
+		if test "$init" = "by_config"
+		then
+			if test $# -gt 0
+			then
+				die "$(gettext "path arguments are incompatible with --init-default-path")"
+			fi
+			cmd_init "--" $(git config --get-all submodule.defaultUpdatePath) || return
+		else
+			cmd_init "--" "$@" || return
+		fi
+
 	fi
 
 	{
diff --git a/t/t7400-submodule-basic.sh b/t/t7400-submodule-basic.sh
index 3570f7bb8c..112d86a885 100755
--- a/t/t7400-submodule-basic.sh
+++ b/t/t7400-submodule-basic.sh
@@ -1116,5 +1116,58 @@ test_expect_success 'submodule helper list is not confused by common prefixes' '
 	test_cmp expect actual
 '
 
+test_expect_success 'setup superproject with submodules' '
+	mkdir sub1 &&
+	(
+		cd sub1 &&
+		git init &&
+		test_commit test &&
+		test_commit test2
+	) &&
+	mkdir multisuper &&
+	(
+		cd multisuper &&
+		git init &&
+		git submodule add ../sub1 sub0 &&
+		git submodule add ../sub1 sub1 &&
+		git submodule add ../sub1 sub2 &&
+		git submodule add ../sub1 sub3 &&
+		git commit -m "add some submodules"
+	)
+'
+
+cat >expect <<-EOF
+-sub0
+ sub1 (test2)
+ sub2 (test2)
+ sub3 (test2)
+EOF
+
+test_expect_success 'submodule update --init with a specification' '
+	test_when_finished "rm -rf multisuper_clone" &&
+	pwd=$(pwd) &&
+	git clone file://"$pwd"/multisuper multisuper_clone &&
+	(
+		cd multisuper_clone &&
+		git submodule update --init . ":(exclude)sub0" &&
+		git submodule status |cut -c 1,43- >../actual
+	) &&
+	test_cmp expect actual
+'
+
+test_expect_success 'submodule update --init-default-path' '
+	test_when_finished "rm -rf multisuper_clone" &&
+	pwd=$(pwd) &&
+	git clone file://"$pwd"/multisuper multisuper_clone &&
+	(
+		cd multisuper_clone &&
+		git config submodule.defaultUpdatePath "." &&
+		git config --add submodule.defaultUpdatePath ":(exclude)sub0" &&
+		git submodule update --init-default-path &&
+		git submodule status |cut -c 1,43- >../actual &&
+		test_must_fail git submodule update --init-default-path sub0
+	) &&
+	test_cmp expect actual
+'
 
 test_done