git-submodule: add support for --rebase.

'git submodule update --rebase' rebases your local branch on top of what
would have been checked out to a detached HEAD otherwise.

In some cases, detaching the HEAD when updating a submodule complicates
the workflow to commit to this submodule (checkout master, rebase, then
commit).  For submodules that require frequent updates but infrequent
(if any) commits, a rebase can be executed directly by the git-submodule
command, ensuring that the submodules stay on their respective branches.

git-config key: submodule.$name.rebase (bool)

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 140 insertions, 0 deletions

diff --git a/t/t7406-submodule-update.sh b/t/t7406-submodule-update.sh
new file mode 100755
index 000000000..3442c05d2
--- /dev/null
+++ b/t/t7406-submodule-update.sh
@@ -0,0 +1,140 @@
+#!/bin/sh
+#
+# Copyright (c) 2009 Red Hat, Inc.
+#
+
+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.
+'
+
+. ./test-lib.sh
+
+
+compare_head()
+{
+    sha_master=`git-rev-list --max-count=1 master`
+    sha_head=`git-rev-list --max-count=1 HEAD`
+
+    test "$sha_master" = "$sha_head"
+}
+
+
+test_expect_success 'setup a submodule tree' '
+	echo file > file &&
+	git add file &&
+	test_tick &&
+	git commit -m upstream
+	git clone . super &&
+	git clone super submodule &&
+	(cd super &&
+	 git submodule add ../submodule submodule &&
+	 test_tick &&
+	 git commit -m "submodule" &&
+	 git submodule init submodule
+	) &&
+	(cd submodule &&
+	echo "line2" > file &&
+	git add file &&
+	git commit -m "Commit 2"
+	) &&
+	(cd super &&
+	 (cd submodule &&
+	  git pull --rebase origin
+	 ) &&
+	 git add submodule &&
+	 git commit -m "submodule update"
+	)
+'
+
+test_expect_success 'submodule update detaching the HEAD ' '
+	(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 --rebase staying on master' '
+	(cd super/submodule &&
+	  git checkout master
+	) &&
+	(cd super &&
+	 (cd submodule &&
+	  compare_head
+	 ) &&
+	 git submodule update --rebase submodule &&
+	 cd submodule &&
+	 compare_head
+	)
+'
+
+test_expect_success 'submodule update - rebase true in .git/config' '
+	(cd super &&
+	 git config submodule.submodule.rebase true
+	) &&
+	(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 - rebase false in .git/config but --rebase given' '
+	(cd super &&
+	 git config submodule.submodule.rebase false
+	) &&
+	(cd super/submodule &&
+	  git reset --hard HEAD~1
+	) &&
+	(cd super &&
+	 (cd submodule &&
+	  compare_head
+	 ) &&
+	 git submodule update --rebase submodule &&
+	 cd submodule &&
+	 compare_head
+	)
+'
+
+test_expect_success 'submodule update - rebase false in .git/config' '
+	(cd super &&
+	 git config submodule.submodule.rebase false
+	) &&
+	(cd super/submodule &&
+	  git reset --hard HEAD^
+	) &&
+	(cd super &&
+	 (cd submodule &&
+	  compare_head
+	 ) &&
+	 git submodule update submodule &&
+	 cd submodule &&
+	 ! compare_head
+	)
+'
+
+test_expect_success 'submodule init picks up rebase' '
+	(cd super &&
+	 git config submodule.rebasing.url git://non-existing/git &&
+	 git config submodule.rebasing.path does-not-matter &&
+	 git config submodule.rebasing.rebase true &&
+	 git submodule init rebasing &&
+	 test true = $(git config --bool submodule.rebasing.rebase)
+	)
+'
+
+test_done