feat(compiler): A better error message for invalid selectors

Author: jbdeboer

lib/core_dom/selector.dart

@@ -181,7 +181,7 @@ class _ElementSelector {
   toString() => 'ElementSelector($name)';
 }
 
-List<_SelectorPart> _splitCss(String selector) {
+List<_SelectorPart> _splitCss(String selector, Type type) {
   List<_SelectorPart> parts = [];
   var remainder = selector;
   var match;
@@ -199,7 +199,7 @@ List<_SelectorPart> _splitCss(String selector) {
         throw "Missmatched RegExp $_SELECTOR_REGEXP on $remainder";
       }
     } else {
-      throw "Unknown selector format '$remainder'.";
+      throw "Unknown selector format '$selector' for $type.";
     }
     remainder = remainder.substring(match.end);
   }
@@ -226,7 +226,7 @@ DirectiveSelector directiveSelectorFactory(DirectiveMap directives) {
       textSelector.add(new _ContainsSelector(annotation, match.group(1)));
     } else if ((match = _ATTR_CONTAINS_REGEXP.firstMatch(selector)) != null) {
       attrSelector.add(new _ContainsSelector(annotation, match[1]));
-    } else if ((selectorParts = _splitCss(selector)) != null){
+    } else if ((selectorParts = _splitCss(selector, type)) != null){
       elementSelector.addDirective(selectorParts, new _Directive(type, annotation));
     } else {
       throw new ArgumentError('Unsupported Selector: $selector');

test/core_dom/compiler_spec.dart

@@ -444,21 +444,26 @@ main() => describe('dte.compiler', () {
       });
 
       describe('invalid components', () {
-        beforeEach(module((Module module) {
-          module
-            ..type(MissingSelector);
-          return (Injector _injector) {
-            injector = _injector;
-            $compile = injector.get(Compiler);
-            $rootScope = injector.get(Scope);
-          };
-        }));
-
-        it('should throw a useful error message', () {
+        it('should throw a useful error message for missing selectors', () {
+          module((Module module) {
+            module
+              ..type(MissingSelector);
+          });
           expect(() {
             inject((Compiler c) { });
           }).toThrow('Missing selector annotation for MissingSelector');
         });
+
+
+        it('should throw a useful error message for invalid selector', () {
+          module((Module module) {
+            module
+              ..type(InvalidSelector);
+          });
+          expect(() {
+            inject((Compiler c) { });
+          }).toThrow('Unknown selector format \'buttonbar button\' for InvalidSelector');
+        });
       });
     });
 
@@ -738,10 +743,9 @@ class MyController {
   }
 }
 
-@NgComponent(
-  template: 'boo'
-)
-class MissingSelector {
+@NgComponent()
+class MissingSelector {}
 
-}
+@NgComponent(selector: 'buttonbar button')
+class InvalidSelector {}