ensure only one dialog content is attached

Author: jelbourn

src/components/dialog/dialog-container.ts

@@ -7,6 +7,7 @@ import {
 import {PortalHostDirective} from '@angular2-material/core/portal/portal-directives';
 import {PromiseCompleter} from '@angular2-material/core/async/promise-completer';
 import {MdDialogConfig} from './dialog-config';
+import {MdDialogContentAlreadyAttachedError} from './dialog-errors';
 
 
 /**
@@ -49,20 +50,24 @@ export class MdDialogContainer extends BasePortalHost implements AfterViewInit {
 
         this._deferredAttachPortal = null;
         this._deferredAttachCompleter = null;
-      });
+      }, () => this._deferredAttachCompleter.reject());
     }
   }
 
   /** Attach a portal as content to this dialog container. */
   attachComponentPortal<T>(portal: ComponentPortal<T>): Promise<ComponentRef<T>> {
     if (this._portalHost) {
+      if (this._portalHost.hasAttached()) {
+        throw new MdDialogContentAlreadyAttachedError();
+      }
+
       return this._portalHost.attachComponentPortal(portal);
     } else {
       // The @ViewChild query for the portalHost is not resolved until AfterViewInit, but this
       // function may be called before this lifecycle event. As such, we defer the attachment of
       // the portal until AfterViewInit.
       if (this._deferredAttachCompleter) {
-        this._deferredAttachCompleter.reject();
+        throw new MdDialogContentAlreadyAttachedError();
       }
 
       this._deferredAttachPortal = portal;

src/components/dialog/dialog-errors.ts

@@ -0,0 +1,8 @@
+import {MdError} from '@angular2-material/core/errors/error';
+
+/** Exception thrown when a ComponentPortal is attached to a DomPortalHost without an origin. */
+export class MdDialogContentAlreadyAttachedError extends MdError {
+  constructor() {
+      super('Attempting to attach dialog content after content is already attached');
+  }
+}

src/components/dialog/dialog.spec.ts

@@ -89,7 +89,7 @@ describe('MdDialog', () => {
 
 /** Runs the necessary detectChanges for a dialog to complete its opening. */
 function detectChangesForDialogOpen(fixture: ComponentFixture<ComponentWithChildViewContainer>) {
-  // TODO(jelbourn): figure out why the test zone is "stable" when where are still pending
+  // TODO(jelbourn): figure out why the test zone is "stable" when there are still pending
   // tasks, such that we have to use `setTimeout` to run the second round of change detection.
   // Two rounds of change detection are necessary: one to *create* the dialog container, and
   // another to cause the lifecycle events of the container to run and load the dialog content.