Support optional trailing comma in attribute argument list

Author: theodorejb

Zend/tests/attributes/027_trailing_comma_args.phpt

@@ -0,0 +1,30 @@
+--TEST--
+Trailing comma in attribute argument list
+--FILE--
+<?php
+
+@@MyAttribute(
+	"there",
+	"are",
+	"many",
+	"arguments",
+)
+class Foo { }
+
+$ref = new \ReflectionClass(Foo::class);
+$attr = $ref->getAttributes()[0];
+var_dump($attr->getName(), $attr->getArguments());
+
+?>
+--EXPECT--
+string(11) "MyAttribute"
+array(4) {
+  [0]=>
+  string(5) "there"
+  [1]=>
+  string(3) "are"
+  [2]=>
+  string(4) "many"
+  [3]=>
+  string(9) "arguments"
+}

Zend/zend_language_parser.y

@@ -330,7 +330,7 @@ attribute:
 			{ $$ = zend_ast_create(ZEND_AST_ATTRIBUTE, $1, NULL); }
 	|	T_ATTRIBUTE '(' ')'
 			{ $$ = zend_ast_create(ZEND_AST_ATTRIBUTE, $1, NULL); }
-	|	T_ATTRIBUTE '(' attribute_arguments ')'
+	|    T_ATTRIBUTE '(' attribute_arguments possible_comma ')'
 			{ $$ = zend_ast_create(ZEND_AST_ATTRIBUTE, $1, $3); }
 ;