Fix Error.prototype.toString to be ES5 conform.

test/mjsunit/error-tostring.js

+// Copyright 2011 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+
+// Test default string representation of an Error object.
+
+var e = new Error();
+assertEquals('Error', e.toString());
+
+
+// Test printing of cyclic errors which return the empty string for
+// compatibility with Safari and Firefox.
+
+e = new Error();
+e.name = e;
+e.message = e;
+e.stack = "Does not occur in output";
+e.arguments = "Does not occur in output";
+e.type = "Does not occur in output";
+assertEquals('', e.toString());
+
+e = new Error();
+e.name = [ e ];
+e.message = [ e ];
+e.stack = "Does not occur in output";
+e.arguments = "Does not occur in output";
+e.type = "Does not occur in output";
+assertEquals('', e.toString());
+
+
+// Test the sequence in which getters and toString operations are called
+// on a given Error object.  Verify the produced string representation.
+
+function testErrorToString(nameValue, messageValue) {
+  var seq = [];
+  var e = {
+    get name() {
+      seq.push(1);
+      return (nameValue === undefined) ? nameValue : {
+        toString: function() { seq.push(2); return nameValue; }
+      };
+    },
+    get message() {
+      seq.push(3);
+      return (messageValue === undefined) ? messageValue : {
+        toString: function() { seq.push(4); return messageValue; }
+      };
+    }
+  };
+  var string = Error.prototype.toString.call(e);
+  return [string,seq];
+}
+
+assertEquals(["Error",[1,3]], testErrorToString(undefined, undefined));
+assertEquals(["e1",[1,2,3]], testErrorToString("e1", undefined));
+assertEquals(["e1: null",[1,2,3,4]], testErrorToString("e1", null));
+assertEquals(["e1",[1,2,3,4]], testErrorToString("e1", ""));
+assertEquals(["Error: e2",[1,3,4]], testErrorToString(undefined, "e2"));
+assertEquals(["null: e2",[1,2,3,4]], testErrorToString(null, "e2"));
+assertEquals(["e2",[1,2,3,4]], testErrorToString("", "e2"));
+assertEquals(["e1: e2",[1,2,3,4]], testErrorToString("e1", "e2"));