branch: introduce --set-upstream-to

The existing --set-uptream option can cause confusion, as it uses the
usual branch convention of assuming a starting point of HEAD if none
is specified, causing

    git branch --set-upstream origin/master

to create a new local branch 'origin/master' that tracks the current
branch. As --set-upstream already exists, we can't simply change its
behaviour. To work around this, introduce --set-upstream-to which
accepts a compulsory argument indicating what the new upstream branch
should be and one optinal argument indicating which branch to change,
defaulting to HEAD.

The new options allows us to type

    git branch --set-upstream-to origin/master

to set the current branch's upstream to be origin's master.

Signed-off-by: Carlos Martín Nieto <cmn@elego.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 14 insertions, 0 deletions

diff --git a/t/t3200-branch.sh b/t/t3200-branch.sh
index a17f8b2a40..e9019ac943 100755
--- a/t/t3200-branch.sh
+++ b/t/t3200-branch.sh
@@ -369,6 +369,20 @@ test_expect_success \
     'git tag foobar &&
      test_must_fail git branch --track my11 foobar'
 
+test_expect_success 'use --set-upstream-to modify HEAD' \
+    'test_config branch.master.remote foo &&
+     test_config branch.master.merge foo &&
+     git branch my12
+     git branch --set-upstream-to my12 &&
+     test "$(git config branch.master.remote)" = "." &&
+     test "$(git config branch.master.merge)" = "refs/heads/my12"'
+
+test_expect_success 'use --set-upstream-to modify a particular branch' \
+    'git branch my13
+     git branch --set-upstream-to master my13 &&
+     test "$(git config branch.my13.remote)" = "." &&
+     test "$(git config branch.my13.merge)" = "refs/heads/master"'
+
 # Keep this test last, as it changes the current branch
 cat >expect <<EOF
 $_z40 $HEAD $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> 1117150200 +0000	branch: Created from master