branch: error copying or renaming a detached HEAD

In c847f53712 (Detached HEAD (experimental), 2007-01-01) an error
condition was introduced in rename_branch() to prevent renaming, later
also copying, a detached HEAD.

The condition used was checking for NULL in oldname, the source branch
to rename/copy.  That condition cannot be satisfied because if no source
branch is specified, HEAD is going to be used in the call.

The error issued instead is:

	fatal: Invalid branch name: 'HEAD'

Let's remove the condition in copy_or_rename_branch() (the current
function name) and check for HEAD before calling it, dying with the
original intended error if we're in a detached HEAD.

Signed-off-by: Rubén Justo <rjusto@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/branch.c b/builtin/branch.c
index 407517ba68447322b0e9a4ccaff2df5fc83186e9..c964ac7bb420545802312cb2f0231e987a67c1d7 100644 (file)
--- a/builtin/branch.c
+++ b/builtin/branch.c
@@ -520,13 +520,6 @@ static void copy_or_rename_branch(const char *oldname, const char *newname, int
        const char *interpreted_newname = NULL;
        int recovery = 0;
 
-       if (!oldname) {
-               if (copy)
-                       die(_("cannot copy the current branch while not on any."));
-               else
-                       die(_("cannot rename the current branch while not on any."));
-       }
-
        if (strbuf_check_branch_ref(&oldref, oldname)) {
                /*
                 * Bad name --- this could be an attempt to rename a
@@ -827,24 +820,19 @@ int cmd_branch(int argc, const char **argv, const char *prefix)
                strbuf_release(&buf);
 
                return ret;
-       } else if (copy) {
-               if (!argc)
-                       die(_("branch name required"));
-               else if (argc == 1)
-                       copy_or_rename_branch(head, argv[0], 1, copy > 1);
-               else if (argc == 2)
-                       copy_or_rename_branch(argv[0], argv[1], 1, copy > 1);
-               else
-                       die(_("too many branches for a copy operation"));
-       } else if (rename) {
+       } else if (copy || rename) {
                if (!argc)
                        die(_("branch name required"));
+               else if ((argc == 1) && filter.detached)
+                       die(copy? _("cannot copy the current branch while not on any.")
+                               : _("cannot rename the current branch while not on any."));
                else if (argc == 1)
-                       copy_or_rename_branch(head, argv[0], 0, rename > 1);
+                       copy_or_rename_branch(head, argv[0], copy, copy + rename > 1);
                else if (argc == 2)
-                       copy_or_rename_branch(argv[0], argv[1], 0, rename > 1);
+                       copy_or_rename_branch(argv[0], argv[1], copy, copy + rename > 1);
                else
-                       die(_("too many arguments for a rename operation"));
+                       die(copy? _("too many branches for a copy operation")
+                               : _("too many arguments for a rename operation"));
        } else if (new_upstream) {
                struct branch *branch;
                struct strbuf buf = STRBUF_INIT;

diff --git a/t/t3200-branch.sh b/t/t3200-branch.sh
index 7d8edff9c320f04aed15932cde1ad16dbec30f22..38c57de71ba52f91595c1b305064bc3b34d353c7 100755 (executable)
--- a/t/t3200-branch.sh
+++ b/t/t3200-branch.sh
@@ -268,6 +268,17 @@ test_expect_success 'git branch -M topic topic should work when main is checked
        git branch -M topic topic
 '
 
+test_expect_success 'git branch -M and -C fail on detached HEAD' '
+       git checkout HEAD^{} &&
+       test_when_finished git checkout - &&
+       echo "fatal: cannot rename the current branch while not on any." >expect &&
+       test_must_fail git branch -M must-fail 2>err &&
+       test_cmp expect err &&
+       echo "fatal: cannot copy the current branch while not on any." >expect &&
+       test_must_fail git branch -C must-fail 2>err &&
+       test_cmp expect err
+'
+
 test_expect_success 'git branch -v -d t should work' '
        git branch t &&
        git rev-parse --verify refs/heads/t &&