Check early that a new branch is new and valid

If you fail to update refs to change branches in checkout, your index and working tree are left already updated. We don't have an easy way to undo this, but at least we can check things that would make the creation of a new branch fail. These checks were in the shell version, and were lost in the C conversion. The messages are from the shell version, and should probably be made nicer. [jc: added test to t7201] Signed-off-by: Daniel Barkalow <barkalow@iabervon.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Daniel Barkalow committed Sep 21, 2008 at 14:36 UTC 352eadc40024b141e1295693654ec20cc123844f

2 files changed +22

builtin-checkout.c

+12

@@ -565,6 +565,18 @@ no_reference:

565 return checkout_paths(source_tree, pathspec);

566 }

567

568 + if (opts.new_branch) {

569 + struct strbuf buf;

570 + strbuf_init(&buf, 0);

571 + strbuf_addstr(&buf, "refs/heads/");

572 + strbuf_addstr(&buf, opts.new_branch);

573 + if (!get_sha1(buf.buf, rev))

574 + die("git checkout: branch %s already exists", opts.new_branch);

575 + if (check_ref_format(buf.buf))

576 + die("git checkout: we do not like '%s' as a branch name.", opts.new_branch);

577 + strbuf_release(&buf);

578 + }

579 +

580 if (new.name && !new.commit) {

581 die("Cannot switch branch to a non-commit.");

582 }

t/t7201-co.sh

+10

@@ -359,4 +359,14 @@ test_expect_success 'checkout an unmerged path should fail' '

359 test_cmp sample file

360 '

361

362 +test_expect_success 'failing checkout -b should not break working tree' '

363 + git reset --hard master &&

364 + git symbolic-ref HEAD refs/heads/master &&

365 + test_must_fail git checkout -b renamer side^ &&

366 + test $(git symbolic-ref HEAD) = refs/heads/master &&

367 + git diff --exit-code &&

368 + git diff --cached --exit-code

369 +

370 +'

371 +

372 test_done