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[PATCH] git-submodule: add support for --merge.

From
Johan Herland <johan@herland.net>
Date
May 19, 2009, 00:35 UTC
Message-ID
<200905190235.34720.johan@herland.net>
In-Reply-To
<200905182355.21645.johan@herland.net>

'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". Another such alternative is, when updating a submodule to a new commit, to merge that commit into the current branch. This is useful in workflows where 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 with a rebase, but you still want to update your submodule from its upstream.

Config variables: The --rebase patch added submodule.<name>.rebase for turning on --rebase by default for a given submodule. However, a similar submodule.<name>.merge variable cannot be added since it would conflict with submodule.<name>.rebase (they cannot both be true). This patch therefore replaces submodule.<name>.rebase with submodule.<name>.update, which can be set to the following values:

- 'checkout': This specifies the default behaviour in which "git
  submodule update" checks out the new commit to a detached HEAD.
  Leaving submodule.<name>.update unset also causes this behaviour.
- 'rebase': This specifies the --rebase behaviour (and thus replaces
  submodule.<name>.rebase == true), where the local branch in the
  submodule is rebased onto the new commit.
- 'merge': This specifies the new --merge behaviour in which the new
  commit is merged into the submodule's local branch.
Signed-off-by: Johan Herland <johan@herland.net>
---

Here's a patch implementing my suggestion. I have chosen to avoid backwards-compatibility for the submodule.<name>.rebase config variable, since it is not yet present in a released version.

Have fun! :)
...Johan
 Documentation/git-submodule.txt |   19 ++++++++--
 Documentation/gitmodules.txt    |   12 +++++-
 git-submodule.sh                |   43 ++++++++++++++--------
 t/t7406-submodule-update.sh     |   76 ++++++++++++++++++++++++++++++++++-----
 4 files changed, 119 insertions(+), 31 deletions(-)
diff --git a/Documentation/git-submodule.txt b/Documentation/git-submodule.txt
index acd16ac..1cbb181 100644
--- a/Documentation/git-submodule.txt
+++ b/Documentation/git-submodule.txt
@@ -13,7 +13,7 @@ SYNOPSIS
 	      [--reference <repository>] [--] <repository> <path>
 'git submodule' [--quiet] status [--cached] [--] [<path>...]
 'git submodule' [--quiet] init [--] [<path>...]
-'git submodule' [--quiet] update [--init] [-N|--no-fetch] [--rebase]
+'git submodule' [--quiet] update [--init] [-N|--no-fetch] [--rebase|--merge]
 	      [--reference <repository>] [--] [<path>...]
 'git submodule' [--quiet] summary [--summary-limit <n>] [commit] [--] [<path>...]
 'git submodule' [--quiet] foreach <command>
@@ -115,8 +115,9 @@ 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.$name.rebase` is set to `true`.
+	This will make the submodules HEAD be detached unless '--rebase' or
+	'--merge' is specified or the key `submodule.$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
@@ -186,7 +187,17 @@ OPTIONS
 	superproject. If this option is given, the submodule's HEAD will not
 	be detached. If a a merge failure prevents this process, you will have
 	to resolve these failures with linkgit:git-rebase[1].
-	If the key `submodule.$name.rebase` is set to `true`, this option is
+	If the key `submodule.$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.
 
 --reference <repository>::
diff --git a/Documentation/gitmodules.txt b/Documentation/gitmodules.txt
index 7c22c40..5daf750 100644
--- a/Documentation/gitmodules.txt
+++ b/Documentation/gitmodules.txt
@@ -30,8 +30,16 @@ submodule.<name>.path::
 submodule.<name>.url::
 	Defines an url from where the submodule repository can be cloned.
 
-submodule.<name>.rebase::
-	Defines that the submodule should be rebased by default.
+submodule.<name>.update::
+	Defines what to do when the submodule is updated by the superproject.
+	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. 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 '--merge' or '--rebase' options.
 
 
 EXAMPLES
diff --git a/git-submodule.sh b/git-submodule.sh
index bbca183..2a1e73c 100755
--- 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
@@ -18,7 +18,7 @@ quiet=
 reference=
 cached=
 nofetch=
-rebase=
+update=
 
 #
 # print stuff on stdout unless -q was specified
@@ -311,10 +311,10 @@ cmd_init()
 		git config submodule."$name".url "$url" ||
 		die "Failed to register url for submodule path '$path'"
 
-		test true != "$(git config -f .gitmodules --bool \
-			submodule."$name".rebase)" ||
-		git config submodule."$name".rebase true ||
-		die "Failed to register submodule path '$path' as rebasing"
+		upd="$(git config -f .gitmodules submodule."$name".update)"
+		test -z "$upd" ||
+		git config submodule."$name".update "$upd" ||
+		die "Failed to register update mode for submodule path '$path'"
 
 		say "Submodule '$name' ($url) registered for path '$path'"
 	done
@@ -345,7 +345,11 @@ cmd_update()
 			;;
 		-r|--rebase)
 			shift
-			rebase=true
+			update="rebase"
+			;;
+		-m|--merge)
+			shift
+			update="merge"
 			;;
 		--reference)
 			case "$2" in '') usage ;; esac
@@ -379,7 +383,7 @@ cmd_update()
 	do
 		name=$(module_name "$path") || exit
 		url=$(git config submodule."$name".url)
-		rebase_module=$(git config --bool submodule."$name".rebase)
+		update_module=$(git config submodule."$name".update)
 		if test -z "$url"
 		then
 			# Only mention uninitialized submodules when its
@@ -400,9 +404,9 @@ cmd_update()
 			die "Unable to find current revision in submodule path '$path'"
 		fi
 
-		if test true = "$rebase"
+		if ! test -z "$update"
 		then
-			rebase_module=true
+			update_module=$update
 		fi
 
 		if test "$subsha1" != "$sha1"
@@ -420,16 +424,23 @@ cmd_update()
 				die "Unable to fetch in submodule path '$path'"
 			fi
 
-			if test true = "$rebase_module"
-			then
-				command="git-rebase"
+			case "$update_module" in
+			rebase)
+				command="git rebase"
 				action="rebase"
 				msg="rebased onto"
-			else
-				command="git-checkout $force -q"
+				;;
+			merge)
+				command="git merge"
+				action="merge"
+				msg="merged in"
+				;;
+			*)
+				command="git checkout $force -q"
 				action="checkout"
 				msg="checked out"
-			fi
+				;;
+			esac
 
 			(unset GIT_DIR; cd "$path" && $command "$sha1") ||
 			die "Unable to $action '$sha1' in submodule path '$path'"
diff --git a/t/t7406-submodule-update.sh b/t/t7406-submodule-update.sh
index 3442c05..2d33d9e 100755
--- 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
@@ -76,9 +76,23 @@ test_expect_success 'submodule update --rebase staying on master' '
 	)
 '
 
-test_expect_success 'submodule update - rebase true in .git/config' '
+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.rebase true
+	 git config submodule.submodule.update rebase
 	) &&
 	(cd super/submodule &&
 	  git reset --hard HEAD~1
@@ -93,9 +107,9 @@ test_expect_success 'submodule update - rebase true in .git/config' '
 	)
 '
 
-test_expect_success 'submodule update - rebase false in .git/config but --rebase given' '
+test_expect_success 'submodule update - checkout in .git/config but --rebase given' '
 	(cd super &&
-	 git config submodule.submodule.rebase false
+	 git config submodule.submodule.update checkout
 	) &&
 	(cd super/submodule &&
 	  git reset --hard HEAD~1
@@ -110,9 +124,43 @@ test_expect_success 'submodule update - rebase false in .git/config but --rebase
 	)
 '
 
-test_expect_success 'submodule update - rebase false in .git/config' '
+test_expect_success 'submodule update - merge in .git/config' '
 	(cd super &&
-	 git config submodule.submodule.rebase false
+	 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
 	) &&
 	(cd super/submodule &&
 	  git reset --hard HEAD^
@@ -131,9 +179,19 @@ 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 config submodule.rebasing.update rebase &&
 	 git submodule init rebasing &&
-	 test true = $(git config --bool submodule.rebasing.rebase)
+	 test "rebase" = $(git config submodule.rebasing.update)
+	)
+'
+
+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)
 	)
 '
 

-- 
1.6.3.rc0.1.gf800
Previous: Johan HerlandNext: Junio C Hamano
Message 9 of 23 in “What's cooking in git.git (May 2009, #02; Sun, 17)”
  1. Junio C HamanoMay 17, 2009
  2. Jakub NarebskiMay 17, 2009
  3. Junio C HamanoMay 17, 2009
  4. Jakub NarebskiMay 17, 2009
  5. David AguilarMay 17, 2009
  6. Johan HerlandMay 18, 2009
  7. Markus HeidelbergMay 18, 2009
  8. Johan HerlandMay 18, 2009
  9. git-submodule: add support for --merge.Johan Herland, May 19, 2009
  10. Junio C HamanoMay 19, 2009
  11. Johan HerlandMay 19, 2009
  12. Johannes SchindelinMay 19, 2009
  13. Johan HerlandMay 19, 2009
  14. Johannes SchindelinMay 19, 2009
  15. Johan HerlandMay 19, 2009
  16. Johan HerlandMay 25, 2009
  17. Junio C HamanoMay 25, 2009
  18. Johannes SchindelinMay 25, 2009
  19. Avery PennarunMay 25, 2009
  20. Johannes SchindelinMay 25, 2009
  21. Johan HerlandMay 25, 2009
  22. Johan HerlandMay 25, 2009
  23. Peter HuttererMay 25, 2009

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