[PATCH] Do not create bogus branch from flag to git branch

If you run `git branch --help', you will unexpectedly have created a new
branch named "--help".  This simple patch adds logic and a usage
statement to catch this and similar problems, and adds a testcase for it.

Signed-off-by: Amos Waterland <apw@rossby.metr.ou.edu>
Signed-off-by: Junio C Hamano <junkio@cox.net>

t/t3200-branch.sh

@@ -0,0 +1,27 @@
+#!/bin/sh
+#
+# Copyright (c) 2005 Amos Waterland
+#
+
+test_description='git branch --foo should not create bogus branch
+
+This test runs git branch --help and checks that the argument is properly
+handled.  Specifically, that a bogus branch is not created.
+'
+. ./test-lib.sh
+
+test_expect_success \
+    'prepare an trivial repository' \
+    'echo Hello > A &&
+     ../../git-update-index --add A &&
+     ../../git-commit.sh -m "Initial commit."'
+
+test_expect_failure \
+    'git branch --help should return error code' \
+    '../../git-branch.sh --help'
+
+test_expect_failure \
+    'git branch --help should not have created a bogus branch' \
+    'test -f .git/refs/heads/--help'
+
+test_done