git-branch, git-checkout: autosetup for remote branch tracking

In order to track and build on top of a branch 'topic' you track from
your upstream repository, you often would end up doing this sequence:

  git checkout -b mytopic origin/topic
  git config --add branch.mytopic.remote origin
  git config --add branch.mytopic.merge refs/heads/topic

This would first fork your own 'mytopic' branch from the 'topic'
branch you track from the 'origin' repository; then it would set up two
configuration variables so that 'git pull' without parameters does the
right thing while you are on your own 'mytopic' branch.

This commit adds a --track option to git-branch, so that "git
branch --track mytopic origin/topic" performs the latter two actions
when creating your 'mytopic' branch.

If the configuration variable branch.autosetupmerge is set to true, you
do not have to pass the --track option explicitly; further patches in
this series allow setting the variable with a "git remote add" option.
The configuration variable is off by default, and there is a --no-track
option to countermand it even if the variable is set.

Signed-off-by: Paolo Bonzini  <bonzini@gnu.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>

1 files changed, 11 insertions, 6 deletions

diff --git a/git-checkout.sh b/git-checkout.sh
index 14835a4aa..6caa9fdcc 100755
--- a/git-checkout.sh
+++ b/git-checkout.sh
@@ -12,6 +12,7 @@ new=
 new_name=
 force=
 branch=
+track=
 newbranch=
 newbranch_log=
 merge=
@@ -33,7 +34,10 @@ while [ "$#" != "0" ]; do
 			die "git checkout: we do not like '$newbranch' as a branch name."
 		;;
 	"-l")
-		newbranch_log=1
+		newbranch_log=-l
+		;;
+	"--track"|"--no-track")
+		track="$arg"
 		;;
 	"-f")
 		force=1
@@ -85,6 +89,11 @@ while [ "$#" != "0" ]; do
     esac
 done
 
+case "$new_branch,$track" in
+,--*)
+	die "git checkout: --track and --no-track require -b"
+esac
+
 case "$force$merge" in
 11)
 	die "git checkout: -f and -m are incompatible"
@@ -235,11 +244,7 @@ fi
 #
 if [ "$?" -eq 0 ]; then
 	if [ "$newbranch" ]; then
-		if [ "$newbranch_log" ]; then
-			mkdir -p $(dirname "$GIT_DIR/logs/refs/heads/$newbranch")
-			touch "$GIT_DIR/logs/refs/heads/$newbranch"
-		fi
-		git-update-ref -m "checkout: Created from $new_name" "refs/heads/$newbranch" $new || exit
+		git-branch $track $newbranch_log "$newbranch" "$new_name" || exit
 		branch="$newbranch"
 	fi
 	if test -n "$branch"