Add --reference option to git submodule.

This adds --reference option to git submodule add and
git submodule update commands, which is passed to git clone.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Documentation/git-submodule.txt b/Documentation/git-submodule.txt
index 3b8df4467377d73d613f76875c725cbf8544ee77..14256c695b3817014be8ba4f45a62a2cd588939c 100644 (file)
--- a/Documentation/git-submodule.txt
+++ b/Documentation/git-submodule.txt
@@ -9,10 +9,12 @@ git-submodule - Initialize, update or inspect submodules
 SYNOPSIS
 --------
 [verse]
-'git submodule' [--quiet] add [-b branch] [--] <repository> <path>
+'git submodule' [--quiet] add [-b branch]
+             [--reference <repository>] [--] <repository> <path>
 'git submodule' [--quiet] status [--cached] [--] [<path>...]
 'git submodule' [--quiet] init [--] [<path>...]
-'git submodule' [--quiet] update [--init] [-N|--no-fetch] [--] [<path>...]
+'git submodule' [--quiet] update [--init] [-N|--no-fetch]
+             [--reference <repository>] [--] [<path>...]
 'git submodule' [--quiet] summary [--summary-limit <n>] [commit] [--] [<path>...]
 'git submodule' [--quiet] foreach <command>
 'git submodule' [--quiet] sync [--] [<path>...]
@@ -177,6 +179,14 @@ OPTIONS
        This option is only valid for the update command.
        Don't fetch new objects from the remote site.
 
+--reference <repository>::
+       This option is only valid for add and update commands.  These
+       commands sometimes need to clone a remote repository. In this case,
+       this option will be passed to the linkgit:git-clone[1] command.
++
+*NOTE*: Do *not* use this option unless you have read the note
+for linkgit:git-clone[1]'s --reference and --shared options carefully.
+
 <path>...::
        Paths to submodule(s). When specified this will restrict the command
        to only operate on the submodules found at the specified paths.

diff --git a/git-submodule.sh b/git-submodule.sh
index 8e234a4028d22e11baedba11f871d33f56945716..ab1ed02a663b7e6252fe33f5224cb9653bcd50f2 100755 (executable)
--- a/git-submodule.sh
+++ b/git-submodule.sh
@@ -15,6 +15,7 @@ require_work_tree
 command=
 branch=
 quiet=
+reference=
 cached=
 nofetch=
 
@@ -91,6 +92,7 @@ module_clone()
 {
        path=$1
        url=$2
+       reference="$3"
 
        # If there already is a directory at the submodule path,
        # expect it to be empty (since that is the default checkout
@@ -106,7 +108,12 @@ module_clone()
        test -e "$path" &&
        die "A file already exist at path '$path'"
 
-       git-clone -n "$url" "$path" ||
+       if test -n "$reference"
+       then
+               git-clone "$reference" -n "$url" "$path"
+       else
+               git-clone -n "$url" "$path"
+       fi ||
        die "Clone of '$url' into submodule path '$path' failed"
 }
 
@@ -131,6 +138,15 @@ cmd_add()
                -q|--quiet)
                        quiet=1
                        ;;
+               --reference)
+                       case "$2" in '') usage ;; esac
+                       reference="--reference=$2"
+                       shift
+                       ;;
+               --reference=*)
+                       reference="$1"
+                       shift
+                       ;;
                --)
                        shift
                        break
@@ -203,7 +219,7 @@ cmd_add()
                git config submodule."$path".url "$url"
        else
 
-               module_clone "$path" "$realrepo" || exit
+               module_clone "$path" "$realrepo" "$reference" || exit
                (
                        unset GIT_DIR
                        cd "$path" &&
@@ -314,13 +330,22 @@ cmd_update()
                        quiet=1
                        ;;
                -i|--init)
+                       init=1
                        shift
-                       cmd_init "$@" || return
                        ;;
                -N|--no-fetch)
                        shift
                        nofetch=1
                        ;;
+               --reference)
+                       case "$2" in '') usage ;; esac
+                       reference="--reference=$2"
+                       shift 2
+                       ;;
+               --reference=*)
+                       reference="$1"
+                       shift
+                       ;;
                --)
                        shift
                        break
@@ -334,6 +359,11 @@ cmd_update()
                esac
        done
 
+       if test -n "$init"
+       then
+               cmd_init "--" "$@" || return
+       fi
+
        module_list "$@" |
        while read mode sha1 stage path
        do
@@ -351,7 +381,7 @@ cmd_update()
 
                if ! test -d "$path"/.git -o -f "$path"/.git
                then
-                       module_clone "$path" "$url" || exit
+                       module_clone "$path" "$url" "$reference"|| exit
                        subsha1=
                else
                        subsha1=$(unset GIT_DIR; cd "$path" &&

diff --git a/t/t7406-submodule-reference.sh b/t/t7406-submodule-reference.sh
new file mode 100755 (executable)
index 0000000..cc16d3f
--- /dev/null
+++ b/t/t7406-submodule-reference.sh
@@ -0,0 +1,81 @@
+#!/bin/sh
+#
+# Copyright (c) 2009, Red Hat Inc, Author: Michael S. Tsirkin (mst@redhat.com)
+#
+
+test_description='test clone --reference'
+. ./test-lib.sh
+
+base_dir=`pwd`
+
+U=$base_dir/UPLOAD_LOG
+
+test_expect_success 'preparing first repository' \
+'test_create_repo A && cd A &&
+echo first > file1 &&
+git add file1 &&
+git commit -m A-initial'
+
+cd "$base_dir"
+
+test_expect_success 'preparing second repository' \
+'git clone A B && cd B &&
+echo second > file2 &&
+git add file2 &&
+git commit -m B-addition &&
+git repack -a -d &&
+git prune'
+
+cd "$base_dir"
+
+test_expect_success 'preparing supermodule' \
+'test_create_repo super && cd super &&
+echo file > file &&
+git add file &&
+git commit -m B-super-initial'
+
+cd "$base_dir"
+
+test_expect_success 'submodule add --reference' \
+'cd super && git submodule add --reference ../B "file://$base_dir/A" sub &&
+git commit -m B-super-added'
+
+cd "$base_dir"
+
+test_expect_success 'after add: existence of info/alternates' \
+'test `wc -l <super/sub/.git/objects/info/alternates` = 1'
+
+cd "$base_dir"
+
+test_expect_success 'that reference gets used with add' \
+'cd super/sub &&
+echo "0 objects, 0 kilobytes" > expected &&
+git count-objects > current &&
+diff expected current'
+
+cd "$base_dir"
+
+test_expect_success 'cloning supermodule' \
+'git clone super super-clone'
+
+cd "$base_dir"
+
+test_expect_success 'update with reference' \
+'cd super-clone && git submodule update --init --reference ../B'
+
+cd "$base_dir"
+
+test_expect_success 'after update: existence of info/alternates' \
+'test `wc -l <super-clone/sub/.git/objects/info/alternates` = 1'
+
+cd "$base_dir"
+
+test_expect_success 'that reference gets used with update' \
+'cd super-clone/sub &&
+echo "0 objects, 0 kilobytes" > expected &&
+git count-objects > current &&
+diff expected current'
+
+cd "$base_dir"
+
+test_done