fix: throws an error if app building fails

cherry-pick from e7f6a51 of angular-cli-ghpages/master by @masaxsuzu
see angular-schule/angular-cli-ghpages#85

Author: masaxsuzu

src/deploy/actions.spec.ts

@@ -3,7 +3,8 @@ import {
   BuilderContext,
   BuilderRun,
   ScheduleOptions,
-  Target
+  Target,
+  BuilderOutput
 } from '@angular-devkit/architect/src/index';
 import deploy from './actions';
 
@@ -60,6 +61,25 @@ describe('Deploy Angular apps', () => {
         expect(e.message).toMatch(/Cannot execute the build target/);
       }
     });
+
+    it('throws if app building fails', async () => {
+      context.scheduleTarget = (
+        _: Target,
+        __?: JsonObject,
+        ___?: ScheduleOptions
+      ) =>
+        Promise.resolve({
+          result: Promise.resolve(
+            createBuilderOutputMock(false, 'build error test')
+          )
+        } as BuilderRun);
+      try {
+        await deploy(mockEngine, context, 'host', {});
+        fail();
+      } catch (e) {
+        expect(e.message).toMatch(/build error test/);
+      }
+    });
   });
 });
 
@@ -90,6 +110,20 @@ const initMocks = () => {
     scheduleBuilder: (_: string, __?: JsonObject, ___?: ScheduleOptions) =>
       Promise.resolve({} as BuilderRun),
     scheduleTarget: (_: Target, __?: JsonObject, ___?: ScheduleOptions) =>
-      Promise.resolve({} as BuilderRun)
+      Promise.resolve({
+        result: Promise.resolve(createBuilderOutputMock(true, ''))
+      } as BuilderRun)
+  };
+};
+
+const createBuilderOutputMock = (
+  success: boolean,
+  error: string
+): BuilderOutput => {
+  return {
+    info: { info: null },
+    error: error,
+    success: success,
+    target: {} as Target
   };
 };

src/deploy/actions.ts

@@ -46,7 +46,11 @@ export default async function deploy(
       },
       overrides as json.JsonObject
     );
-    await build.result;
+    const buildResult = await build.result;
+
+    if (!buildResult.success) {
+      throw new Error(buildResult.error);
+    }
   }
 
   await engine.run(