[PATCH] git-checkout: fix argument parsing to detect ambiguous arguments.

[Pierre Habouzit <madcoder@debian.org>]

Note that it also fix a bug, git checkout -- <path> would be badly
understood as git checkout <branch> if <path> is ambiguous with a branch.

Testcases included.

Signed-off-by: Pierre Habouzit <madcoder@debian.org>
---

  A user on #git happened to have issues that made me realize that
  builtin-checkout is badly broken wrt argument parseing.

  This clearly needs to be applied to master, probably to maint too.

  The patch is against next though, but should probably apply to other
  branches just fine.


 builtin-checkout.c            |    9 +++++++--
 t/t2010-checkout-ambiguous.sh |   27 +++++++++++++++++++++++++++
 2 files changed, 34 insertions(+), 2 deletions(-)
 create mode 100755 t/t2010-checkout-ambiguous.sh

diff --git a/builtin-checkout.c b/builtin-checkout.c
index fbd5105..1490e8e 100644
--- a/builtin-checkout.c
+++ b/builtin-checkout.c
@@ -438,9 +438,14 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
 
 	opts.track = git_branch_track;
 
-	argc = parse_options(argc, argv, options, checkout_usage, 0);
-	if (argc) {
+	argc = parse_options(argc, argv, options, checkout_usage,
+			     PARSE_OPT_KEEP_DASHDASH);
+
+	if (argc && strcmp(argv[0], "--")) {
 		arg = argv[0];
+
+		if (argc == 1 || strcmp(argv[1], "--"))
+			verify_non_filename(NULL, arg);
 		if (get_sha1(arg, rev))
 			;
 		else if ((new.commit = lookup_commit_reference_gently(rev, 1))) {
diff --git a/t/t2010-checkout-ambiguous.sh b/t/t2010-checkout-ambiguous.sh
new file mode 100755
index 0000000..c1a86a2
--- /dev/null
+++ b/t/t2010-checkout-ambiguous.sh
@@ -0,0 +1,26 @@
+#!/bin/sh
+
+test_description='checkout and pathspecs/refspecs ambiguities'
+
+. ./test-lib.sh
+
+test_expect_success 'setup' '
+	echo hello >world &&
+	git add world &&
+	git commit -m initial &&
+	git branch world
+'
+
+test_expect_success 'branch switching' '
+	git checkout world --
+'
+
+test_expect_success 'checkout world from the index' '
+	git checkout -- world
+'
+
+test_expect_success 'ambiguous call' '
+	test_must_fail git checkout world
+'
+
+test_done
-- 
1.6.0.rc0.154.g60644