Handle non-standard leading whitespace on V8 stack frames (occurs whe…

…n users

have defined Error.prepareStackTrace).

Also, do not format stack trace if every frame is an unrecognized format.

Fixes issue 7994.

javascript/webdriver/stacktrace.js

@@ -353,7 +353,9 @@ webdriver.stacktrace.V8_LOCATION_PATTERN_ = ' (?:\\((.*)\\)|(.*))';
  * @private {!RegExp}
  * @const
  */
-webdriver.stacktrace.V8_STACK_FRAME_REGEXP_ = new RegExp('^    at' +
+webdriver.stacktrace.V8_STACK_FRAME_REGEXP_ = new RegExp('^\\s+at' +
+    // Prevent intersections with IE10 stack frame regex.
+    '(?! (?:Anonymous function|Global code|eval code) )' +
     '(?:' + webdriver.stacktrace.V8_FUNCTION_CALL_PATTERN_ + ')?' +
     webdriver.stacktrace.V8_LOCATION_PATTERN_ + '$');
 
@@ -591,6 +593,18 @@ webdriver.stacktrace.format = function(error) {
   var stack = webdriver.stacktrace.getStack_(error);
   var frames = webdriver.stacktrace.parse_(stack);
 
+  // If the original stack is in an unexpected format, our formatted stack
+  // trace will be a bunch of "    at <anonymous>" lines. If this is the case,
+  // just return the error unmodified to avoid losing information. This is
+  // necessary since the user may have defined a custom stack formatter in
+  // V8 via Error.prepareStackTrace. See issue 7994.
+  var isAnonymousFrame = function(frame) {
+    return frame.toString() === '    at <anonymous>';
+  };
+  if (frames.length && goog.array.every(frames, isAnonymousFrame)) {
+    return error;
+  }
+
   // Older versions of IE simply return [object Error] for toString(), so
   // only use that as a last resort.
   var errorStr = '';

javascript/webdriver/test/stacktrace_test.js

@@ -165,6 +165,11 @@ function testParseStackFrameInV8() {
       '    at Object.assert (http://bar:4000/bar.js?value=(a):150:3)',
       new webdriver.stacktrace.Frame('Object', 'assert', '',
           'http://bar:4000/bar.js?value=(a):150:3'));
+
+  assertStackFrame('Frame with non-standard leading whitespace (issue 7994)',
+      '  at module.exports.runCucumber (/local/dir/path)',
+      new webdriver.stacktrace.Frame('module.exports', 'runCucumber', '',
+          '/local/dir/path'));
 }
 
 function testParseStackFrameInOpera() {
@@ -468,6 +473,19 @@ function testFormatsUsingNameAndMessageIfAvailable() {
   assertEquals('TypeError: boom\n', ret.stack);
 }
 
+function testDoesNotFormatErrorIfOriginalStacktraceIsInAnUnexpectedFormat() {
+  var error = Error('testing');
+  var stack = error.stack = [
+    'Error: testing',
+    '..> at Color.red (http://x:1234)',
+    '..> at Foo.bar (http://y:5678)'
+  ].join('\n');
+
+  var ret = webdriver.stacktrace.format(error);
+  assertEquals(ret, error);
+  assertEquals(stack, error.stack);
+}
+
 function testParseStackFrameInIE10() {
   assertStackFrame('name and path',
       '   at foo (http://bar:4000/bar.js:150:3)',