commit-tree: resurrect command line parsing updates

79a9312 (commit-tree: update the command line parsing, 2011-11-09)
updated the command line parser to understand the usual "flags first
and then non-flag arguments" order, in addition to the original and
a bit unusual "tree comes first and then zero or more -p <parent>".

Unfortunately, ba3c69a (commit: teach --gpg-sign option, 2011-10-05)
broke it by mistake.  Resurrect it, and protect the feature with a
test from future breakages.

Noticed by Keshav Kini
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/commit-tree.c

@@ -48,9 +48,6 @@ int cmd_commit_tree(int argc, const char **argv, const char *prefix)
 	if (argc < 2 || !strcmp(argv[1], "-h"))
 		usage(commit_tree_usage);
 
-	if (get_sha1(argv[1], tree_sha1))
-		die("Not a valid object name %s", argv[1]);
-
 	for (i = 1; i < argc; i++) {
 		const char *arg = argv[i];
 		if (!strcmp(arg, "-p")) {

t/t1100-commit-tree-options.sh

@@ -7,6 +7,9 @@ test_description='git commit-tree options test
 
 This test checks that git commit-tree can create a specific commit
 object by defining all environment variables that it understands.
+
+Also make sure that command line parser understands the normal
+"flags first and then non flag arguments" command line.
 '
 
 . ./test-lib.sh
@@ -42,4 +45,18 @@ test_expect_success \
     'compare commit' \
     'test_cmp expected commit'
 
+
+test_expect_success 'flags and then non flags' '
+	echo comment text |
+	git commit-tree $(cat treeid) >commitid &&
+	echo comment text |
+	git commit-tree $(cat treeid) -p $(cat commitid) >childid-1 &&
+	echo comment text |
+	git commit-tree -p $(cat commitid) $(cat treeid) >childid-2 &&
+	test_cmp childid-1 childid-2 &&
+	git commit-tree $(cat treeid) -m foo >childid-3 &&
+	git commit-tree -m foo $(cat treeid) >childid-4 &&
+	test_cmp childid-3 childid-4
+'
+
 test_done