git-check-attr: Fix command-line handling to match docs

According to the git-check-attr synopsis, if the '--stdin' option is
used then no pathnames are expected on the command line.  Change the
behavior to match this description; namely, if '--stdin' is used but
not '--', then treat all command-line arguments as attribute names.
Signed-off-by: NMichael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Documentation/git-check-attr.txt

@@ -33,8 +33,11 @@ OPTIONS
 
 \--::
 	Interpret all preceding arguments as attributes and all following
-	arguments as path names. If not supplied, only the first argument will
-	be treated as an attribute.
+	arguments as path names.
+
+If none of `--stdin`, `--all`, or `--` is used, the first argument
+will be treated as an attribute and the rest of the arguments as
+pathnames.
 
 OUTPUT
 ------

builtin/check-attr.c

@@ -111,15 +111,18 @@ int cmd_check_attr(int argc, const char **argv, const char *prefix)
 	} else if (doubledash == 0) {
 		error_with_usage("No attribute specified");
 	} else if (doubledash < 0) {
-		/*
-		 * There is no double dash; treat the first
-		 * argument as an attribute.
-		 */
 		if (!argc)
 			error_with_usage("No attribute specified");
 
-		cnt = 1;
-		filei = 1;
+		if (stdin_paths) {
+			/* Treat all arguments as attribute names. */
+			cnt = argc;
+			filei = argc;
+		} else {
+			/* Treat exactly one argument as an attribute name. */
+			cnt = 1;
+			filei = 1;
+		}
 	} else {
 		cnt = doubledash;
 		filei = doubledash + 1;

t/t0003-attributes.sh

@@ -70,7 +70,6 @@ test_expect_success 'command line checks' '
 	echo "f" | test_must_fail git check-attr --stdin &&
 	echo "f" | test_must_fail git check-attr --stdin -- f &&
 	echo "f" | test_must_fail git check-attr --stdin test -- f &&
-	echo "f" | test_must_fail git check-attr --stdin test f &&
 	test_must_fail git check-attr "" -- f
 
 '