branch: allow -f with -m and -d

-f/--force is the standard way to force an action, and is used by branch
for the recreation of existing branches, but not for deleting unmerged
branches nor for renaming to an existing branch.

Make "-m -f" equivalent to "-M" and "-d -f" equivalent to" -D", i.e.
allow -f/--force to be used with -m/-d also.

For the list modes, "-f" is simply ignored.

Signed-off-by: Michael J Gruber <git@drmicha.warpmail.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/branch.c

@@ -790,7 +790,7 @@ static int edit_branch_description(const char *branch_name)
 
 int cmd_branch(int argc, const char **argv, const char *prefix)
 {
-	int delete = 0, rename = 0, force_create = 0, list = 0;
+	int delete = 0, rename = 0, force = 0, list = 0;
 	int verbose = 0, abbrev = -1, detached = 0;
 	int reflog = 0, edit_description = 0;
 	int quiet = 0, unset_upstream = 0;
@@ -838,7 +838,7 @@ int cmd_branch(int argc, const char **argv, const char *prefix)
 		OPT_BOOL('l', "create-reflog", &reflog, N_("create the branch's reflog")),
 		OPT_BOOL(0, "edit-description", &edit_description,
 			 N_("edit the description for the branch")),
-		OPT__FORCE(&force_create, N_("force creation (when already exists)")),
+		OPT__FORCE(&force, N_("force creation, move/rename, deletion")),
 		{
 			OPTION_CALLBACK, 0, "no-merged", &merge_filter_ref,
 			N_("commit"), N_("print only not merged branches"),
@@ -884,7 +884,7 @@ int cmd_branch(int argc, const char **argv, const char *prefix)
 	if (with_commit || merge_filter != NO_FILTER)
 		list = 1;
 
-	if (!!delete + !!rename + !!force_create + !!new_upstream +
+	if (!!delete + !!rename + !!new_upstream +
 	    list + unset_upstream > 1)
 		usage_with_options(builtin_branch_usage, options);
 
@@ -897,6 +897,11 @@ int cmd_branch(int argc, const char **argv, const char *prefix)
 		colopts = 0;
 	}
 
+	if (force) {
+		delete *= 2;
+		rename *= 2;
+	}
+
 	if (delete) {
 		if (!argc)
 			die(_("branch name required"));
@@ -1013,7 +1018,7 @@ int cmd_branch(int argc, const char **argv, const char *prefix)
 
 		branch_existed = ref_exists(branch->refname);
 		create_branch(head, argv[0], (argc == 2) ? argv[1] : head,
-			      force_create, reflog, 0, quiet, track);
+			      force, reflog, 0, quiet, track);
 
 		/*
 		 * We only show the instructions if the user gave us

t/t3200-branch.sh

@@ -106,6 +106,11 @@ test_expect_success 'git branch -M o/q o/p should work when o/p exists' '
 	git branch -M o/q o/p
 '
 
+test_expect_success 'git branch -m -f o/q o/p should work when o/p exists' '
+	git branch o/q &&
+	git branch -m -f o/q o/p
+'
+
 test_expect_success 'git branch -m q r/q should fail when r exists' '
 	git branch q &&
 	git branch r &&