[PATCH] rebase -i: fix for optional [branch] parameter

[Johannes Schindelin <Johannes.Schindelin@gmx.de>]

When calling "git rebase -i <upstream> <branch>", git should switch
to <branch> first.  This worked before, but I broke it by my
"Shut git rebase -i up" patch.

Fix that, and add a test to make sure that it does not break again.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---

	On Wed, 1 Aug 2007, Alex Riesen wrote:

	> Johannes Schindelin, Wed, Aug 01, 2007 17:57:25 +0200:
	> > On Fri, 13 Jul 2007, Alex Riesen wrote:
	> >
	> > > Could we also have "git rebase <base> <branch>"?
	> > 
	> > Don't we do that already?  AFAICT it is already in the 
	> > synopsis, ever since rebase -i was introduced into the "next" 
	> > branch, on June 25...
	> > 
	> 
	> Err... "git rebase -i <base> <branch>"
	> 
	> Does not work, just checked:
	> 
	>     $ git rebase -i base branch
	>     /usr/local/bin/git-rebase--interactive: 482: cannot create /home/user/projects/tmp/.git/.dotest-merge/output: Directory nonexistent
	>     cat: /home/user/projects/tmp/.git/.dotest-merge/output: No such file or directory
	>     Invalid branchname: branch

	Sorry...

 git-rebase--interactive.sh    |    2 +-
 t/t3404-rebase-interactive.sh |    8 ++++++++
 2 files changed, 9 insertions(+), 1 deletions(-)

diff --git a/git-rebase--interactive.sh b/git-rebase--interactive.sh
index d3addd4..bdec462 100755
--- a/git-rebase--interactive.sh
+++ b/git-rebase--interactive.sh
@@ -405,6 +405,7 @@ do
 
 		require_clean_work_tree
 
+		mkdir "$DOTEST" || die "Could not create temporary $DOTEST"
 		if test ! -z "$2"
 		then
 			output git show-ref --verify --quiet "refs/heads/$2" ||
@@ -418,7 +419,6 @@ do
 
 		test -z "$ONTO" && ONTO=$UPSTREAM
 
-		mkdir "$DOTEST" || die "Could not create temporary $DOTEST"
 		: > "$DOTEST"/interactive || die "Could not mark as interactive"
 		git symbolic-ref HEAD > "$DOTEST"/head-name ||
 			die "Could not get HEAD"
diff --git a/t/t3404-rebase-interactive.sh b/t/t3404-rebase-interactive.sh
index dc436d7..a9b552f 100755
--- a/t/t3404-rebase-interactive.sh
+++ b/t/t3404-rebase-interactive.sh
@@ -98,6 +98,14 @@ test_expect_success 'no changes are a nop' '
 	test $(git rev-parse I) = $(git rev-parse HEAD)
 '
 
+test_expect_success 'test the [branch] option' '
+	git checkout -b dead-end &&
+	git rm file6 &&
+	git commit -m "stop here" &&
+	git rebase -i F branch2 &&
+	test $(git rev-parse I) = $(git rev-parse HEAD)
+'
+
 test_expect_success 'rebase on top of a non-conflicting commit' '
 	git checkout branch1 &&
 	git tag original-branch1 &&
-- 
1.5.3.rc3.112.gf60b6