Bug 1130798 - Return "(?:)" for source of RegExp with empty pattern. r=till

js/src/builtin/RegExp.cpp

@@ -494,7 +494,12 @@ regexp_source_impl(JSContext *cx, CallArgs args)
     if (!src)
         return false;
 
-    args.rval().setString(src);
+    /* Step 7. */
+    if (src->length() == 0)
+        args.rval().setString(cx->names().emptyRegExp);
+    else
+        args.rval().setString(src);
+
     return true;
 }
 

js/src/jit-test/tests/basic/bug513898-regexp.js

@@ -6,10 +6,10 @@
 
 /* Check the undefined pattern is equivalent to empty string. */
 
-assertEq(RegExp(undefined).source, '');
+assertEq(RegExp(undefined).source, '(?:)');
 assertEq(RegExp(undefined).global, false);
 assertEq("test".replace(RegExp(undefined), "*"), '*test');
-assertEq(new RegExp(undefined).source, '');
+assertEq(new RegExp(undefined).source, '(?:)');
 assertEq(new RegExp(undefined).global, false);
 assertEq('test'.replace(new RegExp(undefined), "*"), '*test');
 

js/src/tests/ecma_2/RegExp/constructor-001.js

@@ -40,7 +40,7 @@ AddTestCase(
 
 AddTestCase(
   "(new RegExp()).source",
-  "",
+  "(?:)",
   re.source );
 
 AddTestCase(

js/src/tests/ecma_2/RegExp/function-001.js

@@ -1,66 +0,0 @@
-/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-
-/**
- *  File Name:          RegExp/function-001.js
- *  ECMA Section:       15.7.2.1
- *  Description:        Based on ECMA 2 Draft 7 February 1999
- *
- *  Author:             christine@netscape.com
- *  Date:               19 February 1999
- */
-var SECTION = "RegExp/function-001";
-var VERSION = "ECMA_2";
-var TITLE   = "RegExp( pattern, flags )";
-
-startTest();
-
-/*
- * for each test case, verify:
- * - verify that [[Class]] property is RegExp
- * - prototype property should be set to RegExp.prototype
- * - source is set to the empty string
- * - global property is set to false
- * - ignoreCase property is set to false
- * - multiline property is set to false
- * - lastIndex property is set to 0
- */
-
-RegExp.prototype.getClassProperty = Object.prototype.toString;
-var re = new RegExp();
-
-AddTestCase(
-  "RegExp.prototype.getClassProperty = Object.prototype.toString; " +
-  "(new RegExp()).getClassProperty()",
-  "[object RegExp]",
-  re.getClassProperty() );
-
-AddTestCase(
-  "(new RegExp()).source",
-  "",
-  re.source );
-
-AddTestCase(
-  "(new RegExp()).global",
-  false,
-  re.global );
-
-AddTestCase(
-  "(new RegExp()).ignoreCase",
-  false,
-  re.ignoreCase );
-
-AddTestCase(
-  "(new RegExp()).multiline",
-  false,
-  re.multiline );
-
-AddTestCase(
-  "(new RegExp()).lastIndex",
-  0,
-  re.lastIndex );
-
-test()

js/src/tests/ecma_2/RegExp/properties-001.js

@@ -19,7 +19,7 @@ var BUGNUMBER ="";
 
 startTest();
 
-AddRegExpCases( new RegExp, "",   false, false, false, 0 );
+AddRegExpCases( new RegExp, "(?:)",   false, false, false, 0 );
 AddRegExpCases( /.*/,       ".*", false, false, false, 0 );
 AddRegExpCases( /[\d]{5}/g, "[\\d]{5}", true, false, false, 0 );
 AddRegExpCases( /[\S]?$/i,  "[\\S]?$", false, true, false, 0 );

js/src/tests/ecma_6/RegExp/source.js

@@ -3,9 +3,12 @@ var summary = "Implement RegExp.prototype.source";
 
 print(BUGNUMBER + ": " + summary);
 
+assertEq(RegExp.prototype.source, "(?:)");
 assertEq(/foo/.source, "foo");
 assertEq(/foo/iymg.source, "foo");
 assertEq(/\//.source, "\\/");
+assertEq(RegExp("").source, "(?:)");
+assertEq(RegExp("", "mygi").source, "(?:)");
 assertEq(RegExp("/").source, "\\/");
 
 assertThrowsInstanceOf(() => genericSource(), TypeError);

js/src/vm/CommonPropertyNames.h

@@ -64,6 +64,7 @@
     macro(each, each, "each") \
     macro(elementType, elementType, "elementType") \
     macro(empty, empty, "") \
+    macro(emptyRegExp, emptyRegExp, "(?:)") \
     macro(encodeURI, encodeURI, "encodeURI") \
     macro(encodeURIComponent, encodeURIComponent, "encodeURIComponent") \
     macro(enumerable, enumerable, "enumerable") \