fix: Handle Schrodingers Error (#1261)

* fix: Handle Schrodingers Error
* ref: Create better description for Schrodinger's Error

Author: kamilogorek

src/raven.js

@@ -461,18 +461,18 @@ Raven.prototype = {
   captureException: function(ex, options) {
     options = objectMerge({trimHeadFrames: 0}, options ? options : {});
 
-    if (isPlainObject(ex)) {
-      // If it is plain Object, serialize it manually and extract options
-      // This will allow us to group events based on top-level keys
-      // which is much better than creating new group when any key/value change
-      options = this._getCaptureExceptionOptionsFromPlainObject(options, ex);
-      ex = new Error(options.message);
-    } else if (isErrorEvent(ex) && ex.error) {
+    if (isErrorEvent(ex) && ex.error) {
       // If it is an ErrorEvent with `error` property, extract it to get actual Error
       ex = ex.error;
     } else if (isError(ex)) {
       // we have a real Error object
       ex = ex;
+    } else if (isPlainObject(ex)) {
+      // If it is plain Object, serialize it manually and extract options
+      // This will allow us to group events based on top-level keys
+      // which is much better than creating new group when any key/value change
+      options = this._getCaptureExceptionOptionsFromPlainObject(options, ex);
+      ex = new Error(options.message);
     } else {
       // If none of previous checks were valid, then it means that
       // it's not a plain Object

test/raven.test.js

@@ -3066,8 +3066,10 @@ describe('Raven (public API)', function() {
         var error = new ErrorEvent('pickleRick', {error: new Error('pickleRick')});
         this.sinon.stub(Raven, 'isSetup').returns(true);
         this.sinon.stub(Raven, '_handleStackInfo');
+        this.sinon.spy(Raven, '_getCaptureExceptionOptionsFromPlainObject');
         Raven.captureException(error, {foo: 'bar'});
         assert.isTrue(Raven._handleStackInfo.calledOnce);
+        assert.isFalse(Raven._getCaptureExceptionOptionsFromPlainObject.called);
       });
 
       it('should send ErrorEvents without Errors as messages', function() {
@@ -3079,6 +3081,44 @@ describe('Raven (public API)', function() {
       });
     }
 
+    it("should treat Schrodinger's Error in the same way as regular Error", function() {
+      // Schrodinger's Error is an object that is and is not an Error at the same time
+      // Like... error, but not really.
+      // But error.
+      //
+      // To be more exact, it's an object literal or an instance of constructor function
+      // that has it's prototype set to the Error object itself.
+      // When using `isPlanObject`, which makes a call to `Object.prototype.toString`,
+      // it returns `[object Object]`, because any instance created with `new X`
+      // where X is a custom constructor like `function X () {}`, it's return value
+      // is an object literal.
+      // However, because it has it's prototype set to an Error object,
+      // when using `instanceof Error` check, it returns `true`, because calls
+      // like this, are always going up the prototype chain and will verify
+      // all possible constructors. For example:
+      //
+      // class Foo extends Bar {}
+      // class Bar extends Error {}
+      //
+      // var foo = new Foo();
+      //
+      // and now `foo` is instance of every "extension" ever created in the chain
+      //
+      // foo instanceof Foo; // true
+      // foo instanceof Bar; // true (because Foo extends Bar)
+      // foo instanceof Error; // true (because Foo extends Bar that extends Error)
+
+      function SchrodingersError() {}
+      SchrodingersError.prototype = new Error("Schrödinger's cat was here");
+      var error = new SchrodingersError();
+      this.sinon.stub(Raven, 'isSetup').returns(true);
+      this.sinon.stub(Raven, '_handleStackInfo');
+      this.sinon.spy(Raven, '_getCaptureExceptionOptionsFromPlainObject');
+      Raven.captureException(error, {foo: 'bar'});
+      assert.isTrue(Raven._handleStackInfo.calledOnce);
+      assert.isFalse(Raven._getCaptureExceptionOptionsFromPlainObject.called);
+    });
+
     it('should call handleStackInfo', function() {
       var error = new Error('pickleRick');
       this.sinon.stub(Raven, 'isSetup').returns(true);