fix(@angular-devkit/architect): properly report errors thrown by builder

When they are thrown by the builder itself.

packages/angular_devkit/architect/src/create-builder.ts

@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 import { experimental, isPromise, json, logging } from '@angular-devkit/core';
-import { Observable, Subscription, from, isObservable, of } from 'rxjs';
+import { Observable, Subscription, from, isObservable, of, throwError } from 'rxjs';
 import { tap } from 'rxjs/operators';
 import {
   BuilderContext,
@@ -14,6 +14,7 @@ import {
   BuilderInfo,
   BuilderInput,
   BuilderOutput,
+  BuilderOutputLike,
   BuilderProgressState,
   Target,
   TypedBuilderProgress,
@@ -148,7 +149,12 @@ export function createBuilder<
         };
 
         context.reportRunning();
-        let result = fn(i.options as OptT, context);
+        let result: BuilderOutputLike;
+        try {
+          result = fn(i.options as OptT, context);
+        } catch (e) {
+          result = throwError(e);
+        }
 
         if (isPromise(result)) {
           result = from(result);

packages/angular_devkit/architect/src/index2_spec.ts

@@ -9,7 +9,7 @@ import { schema } from '@angular-devkit/core';
 import { timer } from 'rxjs';
 import { map, take, tap, toArray } from 'rxjs/operators';
 import { TestingArchitectHost } from '../testing/testing-architect-host';
-import { BuilderOutput } from './api';
+import { BuilderOutput, BuilderRun } from './api';
 import { Architect } from './architect';
 import { createBuilder } from './create-builder';
 
@@ -135,4 +135,54 @@ describe('architect', () => {
     expect(results).toBe(10);
     expect(all.length).toBe(10);
   });
+
+  it('reports errors in the builder', async () => {
+    testArchitectHost.addBuilder('package:error', createBuilder(() => {
+      throw new Error('Error in the builder.');
+    }));
+
+    let run: BuilderRun | undefined = undefined;
+    try {
+      try {
+        // This should not throw.
+        run = await architect.scheduleBuilder('package:error', {});
+      } catch (err) {
+        expect(err).toBeUndefined();
+        throw err;
+      }
+
+      // This should throw.
+      await run.result;
+      expect('to throw').not.toEqual('to throw');
+    } catch {
+    }
+    if (run) {
+      await run.stop();
+    }
+  });
+
+  it('reports errors in the builder (async)', async () => {
+    testArchitectHost.addBuilder('package:error', createBuilder(() => {
+      return new Promise((_, reject) => reject(new Error('Error async')));
+    }));
+
+    let run: BuilderRun | undefined = undefined;
+    try {
+      try {
+        // This should not throw.
+        run = await architect.scheduleBuilder('package:error', {});
+      } catch (err) {
+        expect(err).toBeUndefined();
+        throw err;
+      }
+
+      // This should throw.
+      await run.result;
+      expect('to throw').not.toEqual('to throw');
+    } catch {
+    }
+    if (run) {
+      await run.stop();
+    }
+  });
 });