push: allow unqualified dest refspecs to DWIM

Previously, a push like:

  git push remote src:dst

would go through the following steps:

  1. check for an unambiguous 'dst' on the remote; if it
     exists, then push to that ref
  2. otherwise, check if 'dst' begins with 'refs/'; if it
     does, create a new ref
  3. otherwise, complain because we don't know where in the
     refs hierarchy to put 'dst'

However, in some cases, we can guess about the ref type of
'dst' based on the ref type of 'src'. Specifically, before
complaining we now check:

  2.5. if 'src' resolves to a ref starting with refs/heads
       or refs/tags, then prepend that to 'dst'

So now this creates a new branch on the remote, whereas it
previously failed with an error message:

  git push master:newbranch

Note that, by design, we limit this DWIM behavior only to
source refs which resolve exactly (including symrefs which
resolve to existing refs). We still complain on a partial
destination refspec if the source is a raw sha1, or a ref
expression such as 'master~10'.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 40 insertions, 0 deletions

diff --git a/t/t5516-fetch-push.sh b/t/t5516-fetch-push.sh
index f93a100f8..0a757d5b9 100755
--- a/t/t5516-fetch-push.sh
+++ b/t/t5516-fetch-push.sh
@@ -273,6 +273,37 @@ test_expect_success 'push with colon-less refspec (4)' '
 
 '
 
+test_expect_success 'push head with non-existant, incomplete dest' '
+
+	mk_test &&
+	git push testrepo master:branch &&
+	check_push_result $the_commit heads/branch
+
+'
+
+test_expect_success 'push tag with non-existant, incomplete dest' '
+
+	mk_test &&
+	git tag -f v1.0 &&
+	git push testrepo v1.0:tag &&
+	check_push_result $the_commit tags/tag
+
+'
+
+test_expect_success 'push sha1 with non-existant, incomplete dest' '
+
+	mk_test &&
+	test_must_fail git push testrepo `git rev-parse master`:foo
+
+'
+
+test_expect_success 'push ref expression with non-existant, incomplete dest' '
+
+	mk_test &&
+	test_must_fail git push testrepo master^:branch
+
+'
+
 test_expect_success 'push with HEAD' '
 
 	mk_test heads/master &&
@@ -311,6 +342,15 @@ test_expect_success 'push with +HEAD' '
 
 '
 
+test_expect_success 'push HEAD with non-existant, incomplete dest' '
+
+	mk_test &&
+	git checkout master &&
+	git push testrepo HEAD:branch &&
+	check_push_result $the_commit heads/branch
+
+'
+
 test_expect_success 'push with config remote.*.push = HEAD' '
 
 	mk_test heads/local &&