Merge branch 'db/maint-checkout-b' into maint

* db/maint-checkout-b:
Check early that a new branch is new and valid

diff --git a/builtin-checkout.c b/builtin-checkout.c
index c4fc2b2c562725018789dead3b86ccfbc4e2925f..1deda927cdfcbcdcb751aca3338ac77ef0aad836 100644 (file)
--- a/builtin-checkout.c
+++ b/builtin-checkout.c
@@ -565,6 +565,18 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
                return checkout_paths(source_tree, pathspec);
        }
 
+       if (opts.new_branch) {
+               struct strbuf buf;
+               strbuf_init(&buf, 0);
+               strbuf_addstr(&buf, "refs/heads/");
+               strbuf_addstr(&buf, opts.new_branch);
+               if (!get_sha1(buf.buf, rev))
+                       die("git checkout: branch %s already exists", opts.new_branch);
+               if (check_ref_format(buf.buf))
+                       die("git checkout: we do not like '%s' as a branch name.", opts.new_branch);
+               strbuf_release(&buf);
+       }
+
        if (new.name && !new.commit) {
                die("Cannot switch branch to a non-commit.");
        }

diff --git a/t/t7201-co.sh b/t/t7201-co.sh
index fbec70d3c6abff4a97aa205aa10fbf6fe336fa5f..0679abd29d907944c5c246275adfcd760f001d55 100755 (executable)
--- a/t/t7201-co.sh
+++ b/t/t7201-co.sh
@@ -359,4 +359,14 @@ test_expect_success 'checkout an unmerged path should fail' '
        test_cmp sample file
 '
 
+test_expect_success 'failing checkout -b should not break working tree' '
+       git reset --hard master &&
+       git symbolic-ref HEAD refs/heads/master &&
+       test_must_fail git checkout -b renamer side^ &&
+       test $(git symbolic-ref HEAD) = refs/heads/master &&
+       git diff --exit-code &&
+       git diff --cached --exit-code
+
+'
+
 test_done