fix($log): don't parse error stacks manually outside of IE/Edge

IE/Edge display errors in such a way that it requires the user to click in
4 places to see the stack trace. There is no way to feature-detect it so
there's a chance of the user agent sniffing to go wrong but since it's only
about logging, this shouldn't break apps. Other browsers display errors in
a sensible way and some of them map stack traces along source maps if available
so it makes sense to let browsers display it as they want.

Fixes angular#15590

Author: mgol

src/ng/log.js

@@ -124,7 +124,14 @@ function $LogProvider() {
 
     function formatError(arg) {
       if (arg instanceof Error) {
-        if (arg.stack) {
+        // Support: IE 9-11, Edge 12-14+
+        // IE/Edge display errors in such a way that it requires the user to click in 4 places
+        // to see the stack trace. There is no way to feature-detect it so there's a chance
+        // of the user agent sniffing to go wrong but since it's only about logging, this shouldn't
+        // break apps. Other browsers display errors in a sensible way and some of them map stack
+        // traces along source maps if available so it makes sense to let browsers display it
+        // as they want.
+        if (arg.stack && (msie || /\bEdge\//.test($window.navigator.userAgent))) {
           arg = (arg.message && arg.stack.indexOf(arg.message) === -1)
               ? 'Error: ' + arg.message + '\n' + arg.stack
               : arg.stack;

test/ng/logSpec.js

@@ -7,7 +7,7 @@ describe('$log', function() {
 
 
   beforeEach(module(function($provide) {
-    $window = {navigator: {}, document: {}};
+    $window = {navigator: {userAgent: ''}, document: {}};
     logger = '';
     log = function() { logger += 'log;'; };
     warn = function() { logger += 'warn;'; };
@@ -131,12 +131,12 @@ describe('$log', function() {
         $log.debug();
         expect(logger).toEqual('log;warn;info;error;');
       }
-  ));
+    ));
 
   });
 
   describe('$log.error', function() {
-    var e, $log, errorArgs;
+    var e, $log;
 
     function TestError() {
       Error.prototype.constructor.apply(this, arguments);
@@ -148,38 +148,81 @@ describe('$log', function() {
     TestError.prototype = Object.create(Error.prototype);
     TestError.prototype.constructor = TestError;
 
-    beforeEach(function() {
-      e = new TestError('');
-      var mockWindow = {
-        console: {
-          error: function() {
-            errorArgs = [].slice.call(arguments, 0);
+    [
+      {
+        browser: 'Chrome',
+        msie: undefined,
+        userAgent: 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_3) AppleWebKit/537.36 ' +
+          '(KHTML, like Gecko) Chrome/56.0.2924.87 Safari/537.36'
+      },
+      {
+        browser: 'Firefox',
+        msie: undefined,
+        userAgent: 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:51.0) ' +
+          'Gecko/20100101 Firefox/51.0'
+      },
+      {
+        browser: 'Safari',
+        msie: undefined,
+        userAgent: 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_3) AppleWebKit/602.4.8 ' +
+          '(KHTML, like Gecko) Version/10.0.3 Safari/602.4.8'
+      },
+      {
+        browser: 'Edge',
+        msie: undefined,
+        userAgent: 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 ' +
+          '(KHTML, like Gecko) Chrome/51.0.2704.79 Safari/537.36 Edge/14.14393'
+      },
+      {
+        browser: 'IE',
+        msie: 11,
+        userAgent: 'Mozilla/5.0 (Windows NT 10.0; WOW64; Trident/7.0; .NET4.0C; .NET4.0E; rv:11.0) like Gecko'
+      }
+    ].forEach(function(options) {
+      describe('(in ' + options.browser + ')', function() {
+        beforeEach(inject(
+          function() {
+            e = new TestError('');
+            $window.console = {
+              error: jasmine.createSpy('error')
+            };
+            $window.navigator.userAgent = options.userAgent;
+            msie = options.msie;
+          },
+
+          function(_$log_) {
+            $log = _$log_;
           }
+        ));
+
+
+        it('should pass error if does not have trace', function() {
+          $log.error('abc', e);
+          expect($window.console.error).toHaveBeenCalledWith('abc', e);
+        });
+
+        if (options.browser === 'IE' || options.browser === 'Edge') {
+          it('should print stack', function() {
+            e.stack = 'stack';
+            $log.error('abc', e);
+            expect($window.console.error).toHaveBeenCalledWith('abc', 'stack');
+          });
+        } else {
+          it('should print a raw error', function() {
+            e.stack = 'stack';
+            $log.error('abc', e);
+            expect($window.console.error).toHaveBeenCalledWith('abc', e);
+          });
         }
-      };
-      $log = new $LogProvider().$get[1](mockWindow);
-    });
-
-
-    it('should pass error if does not have trace', function() {
-      $log.error('abc', e);
-      expect(errorArgs).toEqual(['abc', e]);
-    });
-
-
-    it('should print stack', function() {
-      e.stack = 'stack';
-      $log.error('abc', e);
-      expect(errorArgs).toEqual(['abc', 'stack']);
-    });
-
 
-    it('should print line', function() {
-      e.message = 'message';
-      e.sourceURL = 'sourceURL';
-      e.line = '123';
-      $log.error('abc', e);
-      expect(errorArgs).toEqual(['abc', 'message\nsourceURL:123']);
+        it('should print line', function() {
+          e.message = 'message';
+          e.sourceURL = 'sourceURL';
+          e.line = '123';
+          $log.error('abc', e);
+          expect($window.console.error).toHaveBeenCalledWith('abc', 'message\nsourceURL:123');
+        });
+      });
     });
   });