handle empty stacktraces (#605)

Author: hmalphettes

features/custom_stack_trace.feature

@@ -0,0 +1,37 @@
+Feature: Custom stack trace
+
+  Scenario: Error.prepareStackTrace override
+    Given a file named "features/a.feature" with:
+      """
+      Feature: Some feature
+        Scenario: Some scenario
+          Given Error.prepareStackTrace has been overriden
+      """
+    Given a file named "features/step_definitions/cucumber_steps.js" with:
+      """
+      var cucumberSteps = function() {
+        var _prepareStackTrace = Error.prepareStackTrace;
+        Error.prepareStackTrace = function() {
+          return 'Custom message';
+        }
+
+        this.When(/^Error.prepareStackTrace has been overriden$/, function() {
+        });
+
+        Error.prepareStackTrace = _prepareStackTrace;
+      };
+      module.exports = cucumberSteps;
+      """
+    When I run cucumber.js
+    Then it outputs this text:
+      """
+      Feature: Some feature
+
+        Scenario: Some scenario
+        ✓ Given Error.prepareStackTrace has been overriden
+
+      1 scenario (1 passed)
+      1 step (1 passed)
+      <duration-stat>
+      """
+    And the exit status should be 0

lib/cucumber/support_code/library.js

@@ -24,6 +24,15 @@ function Library(supportCodeDefinition) {
     });
   }
 
+  function getStackframe() {
+    var stackframes = StackTrace.getSync();
+    if (stackframes.length > 2) {
+      return stackframes[2];
+    } else {
+      return stackframes[0];
+    }
+  }
+
   var self = {
     lookupBeforeHooksByScenario: function lookupBeforeHooksByScenario(scenario) {
       return self.lookupHooksByScenario(beforeHooks, scenario);
@@ -53,9 +62,9 @@ function Library(supportCodeDefinition) {
           code = options;
           options = {};
         }
-        var stackframes = StackTrace.getSync();
-        var line = stackframes[1].getLineNumber();
-        var uri = stackframes[1].getFileName() || 'unknown';
+        var stackframe = getStackframe();
+        var line = stackframe.getLineNumber();
+        var uri = stackframe.getFileName() || 'unknown';
         var hook = builder(code, options, uri, line);
         collection.push(hook);
       };
@@ -66,9 +75,9 @@ function Library(supportCodeDefinition) {
         code = options;
         options = {};
       }
-      var stackframes = StackTrace.getSync();
-      var line = stackframes[1].getLineNumber();
-      var uri = stackframes[1].getFileName() || 'unknown';
+      var stackframe = getStackframe();
+      var line = stackframe.getLineNumber();
+      var uri = stackframe.getFileName() || 'unknown';
       var stepDefinition = Cucumber.SupportCode.StepDefinition(name, options, code, uri, line);
       stepDefinitions.push(stepDefinition);
     },
@@ -82,9 +91,9 @@ function Library(supportCodeDefinition) {
         handler = options;
         options = {};
       }
-      var stackframes = StackTrace.getSync();
-      options.line = stackframes[1].getLineNumber();
-      options.uri = stackframes[1].getFileName() || 'unknown';
+      var stackframe = getStackframe();
+      options.line = stackframe.getLineNumber();
+      options.uri = stackframe.getFileName() || 'unknown';
       var listener = Cucumber.Listener(options);
       listener.setHandlerForEvent(eventName, handler);
       self.registerListener(listener);