From 6de68e2f1f2b8403266e94f13f1986dfd09e5969 Mon Sep 17 00:00:00 2001
From: Brian Ford <btford@umich.edu>
Date: Wed, 9 Mar 2016 14:55:27 -0800
Subject: [PATCH] feat(compiler): assert that Component.style is an array

Part of #7481 (effort to improve error messages)

Closes #7559
---
 modules/angular2/src/compiler/assertions.dart    |  3 +++
 modules/angular2/src/compiler/assertions.ts      | 16 ++++++++++++++++
 .../angular2/src/compiler/runtime_metadata.ts    |  3 +++
 .../test/compiler/runtime_metadata_fixture.dart  |  9 +++++++++
 .../test/compiler/runtime_metadata_fixture.ts    |  5 +++++
 .../test/compiler/runtime_metadata_spec.ts       |  9 +++++++++
 6 files changed, 45 insertions(+)
 create mode 100644 modules/angular2/src/compiler/assertions.dart
 create mode 100644 modules/angular2/src/compiler/assertions.ts
 create mode 100644 modules/angular2/test/compiler/runtime_metadata_fixture.dart
 create mode 100644 modules/angular2/test/compiler/runtime_metadata_fixture.ts

diff --git a/modules/angular2/src/compiler/assertions.dart b/modules/angular2/src/compiler/assertions.dart
new file mode 100644
index 0000000000..243292ea57
--- /dev/null
+++ b/modules/angular2/src/compiler/assertions.dart
@@ -0,0 +1,3 @@
+library angular2.core.util.asserions;
+
+void assertArrayOfStrings(String identifier, Object value) {}
diff --git a/modules/angular2/src/compiler/assertions.ts b/modules/angular2/src/compiler/assertions.ts
new file mode 100644
index 0000000000..b402485d03
--- /dev/null
+++ b/modules/angular2/src/compiler/assertions.ts
@@ -0,0 +1,16 @@
+import {isArray, isString, isBlank, assertionsEnabled} from '../facade/lang';
+import {BaseException} from '../facade/exceptions';
+
+export function assertArrayOfStrings(identifier: string, value: any) {
+  if (!assertionsEnabled() || isBlank(value)) {
+    return;
+  }
+  if (!isArray(value)) {
+    throw new BaseException(`Expected '${identifier}' to be an array of strings.`);
+  }
+  for (var i = 0; i < value.length; i += 1) {
+    if (!isString(value[i])) {
+      throw new BaseException(`Expected '${identifier}' to be an array of strings.`);
+    }
+  }
+}
diff --git a/modules/angular2/src/compiler/runtime_metadata.ts b/modules/angular2/src/compiler/runtime_metadata.ts
index 51b3494b4e..d15d2a9229 100644
--- a/modules/angular2/src/compiler/runtime_metadata.ts
+++ b/modules/angular2/src/compiler/runtime_metadata.ts
@@ -20,6 +20,7 @@ import {reflector} from 'angular2/src/core/reflection/reflection';
 import {Injectable, Inject, Optional} from 'angular2/src/core/di';
 import {PLATFORM_DIRECTIVES, PLATFORM_PIPES} from 'angular2/src/core/platform_directives_and_pipes';
 import {MODULE_SUFFIX} from './util';
+import {assertArrayOfStrings} from './assertions';
 import {getUrlScheme} from 'angular2/src/compiler/url_resolver';
 
 @Injectable()
@@ -41,9 +42,11 @@ export class RuntimeMetadataResolver {
       var changeDetectionStrategy = null;
 
       if (dirMeta instanceof md.ComponentMetadata) {
+        assertArrayOfStrings('styles', dirMeta.styles);
         var cmpMeta = <md.ComponentMetadata>dirMeta;
         moduleUrl = calcModuleUrl(directiveType, cmpMeta);
         var viewMeta = this._viewResolver.resolve(directiveType);
+        assertArrayOfStrings('styles', viewMeta.styles);
         templateMeta = new cpl.CompileTemplateMetadata({
           encapsulation: viewMeta.encapsulation,
           template: viewMeta.template,
diff --git a/modules/angular2/test/compiler/runtime_metadata_fixture.dart b/modules/angular2/test/compiler/runtime_metadata_fixture.dart
new file mode 100644
index 0000000000..b26f0f259a
--- /dev/null
+++ b/modules/angular2/test/compiler/runtime_metadata_fixture.dart
@@ -0,0 +1,9 @@
+library angular2.test.compiler.runtime_metadata_fixture;
+
+import "package:angular2/core.dart" show Component;
+
+// This component is not actually malformed; this fixture is here to
+// make Dart not complain about a missing import for a test case that only
+// matters in an JavaScript app.
+@Component(template: "")
+class MalformedStylesComponent {}
diff --git a/modules/angular2/test/compiler/runtime_metadata_fixture.ts b/modules/angular2/test/compiler/runtime_metadata_fixture.ts
new file mode 100644
index 0000000000..74a0a650f3
--- /dev/null
+++ b/modules/angular2/test/compiler/runtime_metadata_fixture.ts
@@ -0,0 +1,5 @@
+import {Component} from 'angular2/core';
+
+@Component({styles:<any>('foo'), template: ''})
+export class MalformedStylesComponent {
+}
diff --git a/modules/angular2/test/compiler/runtime_metadata_spec.ts b/modules/angular2/test/compiler/runtime_metadata_spec.ts
index e74a8cae8c..231d022720 100644
--- a/modules/angular2/test/compiler/runtime_metadata_spec.ts
+++ b/modules/angular2/test/compiler/runtime_metadata_spec.ts
@@ -37,6 +37,7 @@ import {TEST_PROVIDERS} from './test_bindings';
 import {MODULE_SUFFIX} from 'angular2/src/compiler/util';
 import {IS_DART} from 'angular2/src/facade/lang';
 import {PLATFORM_DIRECTIVES} from 'angular2/src/core/platform_directives_and_pipes';
+import {MalformedStylesComponent} from './runtime_metadata_fixture';
 
 export function main() {
   describe('RuntimeMetadataResolver', () => {
@@ -74,6 +75,14 @@ export function main() {
            var expectedEndValue = IS_DART ? 'test/compiler/runtime_metadata_spec.dart' : './';
            expect(value.endsWith(expectedEndValue)).toBe(true);
          }));
+
+      it('should throw when metadata is incorrectly typed',
+         inject([RuntimeMetadataResolver], (resolver: RuntimeMetadataResolver) => {
+           if (!IS_DART) {
+             expect(() => resolver.getDirectiveMetadata(MalformedStylesComponent))
+                 .toThrowError(`Expected 'styles' to be an array of strings.`);
+           }
+         }));
     });
 
     describe('getViewDirectivesMetadata', () => {