1 files changed, 12 insertions, 27 deletions
diff --git a/builtin/branch.c b/builtin/branch.c
index 407517ba68..9470c980c1 100644
--- a/builtin/branch.c
+++ b/builtin/branch.c
@@ -150,7 +150,7 @@ static int branch_merged(int kind, const char *name,
 	if (!reference_rev)
 		reference_rev = head_rev;
 
-	merged = in_merge_bases(rev, reference_rev);
+	merged = reference_rev ? in_merge_bases(rev, reference_rev) : 0;
 
 	/*
 	 * After the safety valve is fully redefined to "check with
@@ -160,7 +160,7 @@ static int branch_merged(int kind, const char *name,
 	 * a gentle reminder is in order.
 	 */
 	if ((head_rev != reference_rev) &&
-	    in_merge_bases(rev, head_rev) != merged) {
+	    (head_rev ? in_merge_bases(rev, head_rev) : 0) != merged) {
 		if (merged)
 			warning(_("deleting branch '%s' that has been merged to\n"
 				"         '%s', but not yet merged to HEAD."),
@@ -235,11 +235,8 @@ static int delete_branches(int argc, const char **argv, int force, int kinds,
 	}
 	branch_name_pos = strcspn(fmt, "%");
 
-	if (!force) {
+	if (!force)
 		head_rev = lookup_commit_reference(the_repository, &head_oid);
-		if (!head_rev)
-			die(_("Couldn't look up commit object for HEAD"));
-	}
 
 	for (i = 0; i < argc; i++, strbuf_reset(&bname)) {
 		char *target = NULL;
@@ -520,13 +517,6 @@ 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
@@ -816,7 +806,7 @@ int cmd_branch(int argc, const char **argv, const char *prefix)
 
 		strbuf_addf(&branch_ref, "refs/heads/%s", branch_name);
 		if (!ref_exists(branch_ref.buf))
-			ret = error((!argc || !strcmp(head, branch_name))
+			error((!argc || !strcmp(head, branch_name))
 			      ? _("No commit on branch '%s' yet.")
 			      : _("No branch named '%s'."),
 			      branch_name);
@@ -827,24 +817,19 @@ 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;