git-submodule: add support for --merge.

'git submodule update --merge' merges the commit referenced by the
superproject into your local branch, instead of checking it out on
a detached HEAD.

As evidenced by the addition of "git submodule update --rebase", it
is useful to provide alternatives to the default 'checkout' behaviour
of "git submodule update". One such alternative is, when updating a
submodule to a new commit, to merge that commit into the current
local branch in that submodule. This is useful in workflows where
you want to update your submodule from its upstream, but you cannot
use --rebase, because you have downstream people working on top of
your submodule branch, and you don't want to disrupt their work.

Signed-off-by: Johan Herland <johan@herland.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Documentation/git-submodule.txt b/Documentation/git-submodule.txt
index f993469dc642d6fc84a07826c3782b8e22e3e223..2289d11f0e350886296bf961a9acb2e9b6f0ffd9 100644 (file)
--- a/Documentation/git-submodule.txt
+++ b/Documentation/git-submodule.txt
@@ -113,8 +113,9 @@ init::
 update::
        Update the registered submodules, i.e. clone missing submodules and
        checkout the commit specified in the index of the containing repository.
-       This will make the submodules HEAD be detached unless '--rebase' is
-       specified or the key `submodule.$name.update` is set to `rebase`.
+       This will make the submodules HEAD be detached unless '--rebase' or
+       '--merge' is specified or the key `submodule.$name.update` is set to
+       `rebase` or `merge`.
 +
 If the submodule is not yet initialized, and you just want to use the
 setting as stored in .gitmodules, you can automatically initialize the
@@ -187,6 +188,16 @@ OPTIONS
        If the key `submodule.$name.update` is set to `rebase`, this option is
        implicit.
 
+--merge::
+       This option is only valid for the update command.
+       Merge the commit recorded in the superproject into the current branch
+       of the submodule. If this option is given, the submodule's HEAD will
+       not be detached. If a merge failure prevents this process, you will
+       have to resolve the resulting conflicts within the submodule with the
+       usual conflict resolution tools.
+       If the key `submodule.$name.update` is set to `merge`, this option is
+       implicit.
+
 <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/Documentation/gitmodules.txt b/Documentation/gitmodules.txt
index 1b67f0a9f12974afca2e8e6948d0fca564b9b17b..5daf750d1942f3b97844b4ef378daf9346cb46d4 100644 (file)
--- a/Documentation/gitmodules.txt
+++ b/Documentation/gitmodules.txt
@@ -35,9 +35,11 @@ submodule.<name>.update::
        If 'checkout' (the default), the new commit specified in the
        superproject will be checked out in the submodule on a detached HEAD.
        If 'rebase', the current branch of the submodule will be rebased onto
-       the commit specified in the superproject.
+       the commit specified in the superproject. If 'merge', the commit
+       specified in the superproject will be merged into the current branch
+       in the submodule.
        This config option is overridden if 'git submodule update' is given
-       the '--rebase' option.
+       the '--merge' or '--rebase' options.
 
 
 EXAMPLES

diff --git a/git-submodule.sh b/git-submodule.sh
index f384c6b2b4953110ab0f892aabdbb826ac2263da..3aff37970ad22c2498e1b2755a214e2fdb183f21 100755 (executable)
--- a/git-submodule.sh
+++ b/git-submodule.sh
@@ -5,7 +5,7 @@
 # Copyright (c) 2007 Lars Hjemli
 
 USAGE="[--quiet] [--cached] \
-[add [-b branch] <repo> <path>]|[status|init|update [-i|--init] [-N|--no-fetch]|summary [-n|--summary-limit <n>] [<commit>]] \
+[add [-b branch] <repo> <path>]|[status|init|update [-i|--init] [-N|--no-fetch] [--rebase|--merge]|summary [-n|--summary-limit <n>] [<commit>]] \
 [--] [<path>...]|[foreach <command>]|[sync [--] [<path>...]]"
 OPTIONS_SPEC=
 . git-sh-setup
@@ -331,6 +331,10 @@ cmd_update()
                        shift
                        update="rebase"
                        ;;
+               -m|--merge)
+                       shift
+                       update="merge"
+                       ;;
                --)
                        shift
                        break
@@ -396,6 +400,11 @@ cmd_update()
                                action="rebase"
                                msg="rebased onto"
                                ;;
+                       merge)
+                               command="git merge"
+                               action="merge"
+                               msg="merged in"
+                               ;;
                        *)
                                command="git checkout $force -q"
                                action="checkout"

diff --git a/t/t7406-submodule-update.sh b/t/t7406-submodule-update.sh
index 0773fe405bb792e82b658c7cea2d8815163ccd19..2d33d9efec3f2f601305e736e31368621acd0584 100755 (executable)
--- a/t/t7406-submodule-update.sh
+++ b/t/t7406-submodule-update.sh
@@ -6,7 +6,7 @@
 test_description='Test updating submodules
 
 This test verifies that "git submodule update" detaches the HEAD of the
-submodule and "git submodule update --rebase" does not detach the HEAD.
+submodule and "git submodule update --rebase/--merge" does not detach the HEAD.
 '
 
 . ./test-lib.sh
@@ -76,6 +76,20 @@ test_expect_success 'submodule update --rebase staying on master' '
        )
 '
 
+test_expect_success 'submodule update --merge staying on master' '
+       (cd super/submodule &&
+         git reset --hard HEAD~1
+       ) &&
+       (cd super &&
+        (cd submodule &&
+         compare_head
+        ) &&
+        git submodule update --merge submodule &&
+        cd submodule &&
+        compare_head
+       )
+'
+
 test_expect_success 'submodule update - rebase in .git/config' '
        (cd super &&
         git config submodule.submodule.update rebase
@@ -110,6 +124,40 @@ test_expect_success 'submodule update - checkout in .git/config but --rebase giv
        )
 '
 
+test_expect_success 'submodule update - merge in .git/config' '
+       (cd super &&
+        git config submodule.submodule.update merge
+       ) &&
+       (cd super/submodule &&
+         git reset --hard HEAD~1
+       ) &&
+       (cd super &&
+        (cd submodule &&
+         compare_head
+        ) &&
+        git submodule update submodule &&
+        cd submodule &&
+        compare_head
+       )
+'
+
+test_expect_success 'submodule update - checkout in .git/config but --merge given' '
+       (cd super &&
+        git config submodule.submodule.update checkout
+       ) &&
+       (cd super/submodule &&
+         git reset --hard HEAD~1
+       ) &&
+       (cd super &&
+        (cd submodule &&
+         compare_head
+        ) &&
+        git submodule update --merge submodule &&
+        cd submodule &&
+        compare_head
+       )
+'
+
 test_expect_success 'submodule update - checkout in .git/config' '
        (cd super &&
         git config submodule.submodule.update checkout
@@ -137,4 +185,14 @@ test_expect_success 'submodule init picks up rebase' '
        )
 '
 
+test_expect_success 'submodule init picks up merge' '
+       (cd super &&
+        git config submodule.merging.url git://non-existing/git &&
+        git config submodule.merging.path does-not-matter &&
+        git config submodule.merging.update merge &&
+        git submodule init merging &&
+        test "merge" = $(git config submodule.merging.update)
+       )
+'
+
 test_done