fix(@angular/cli): honor builder schema additional properties option

Fixes angular#14354

Author: clydin

packages/angular/cli/models/architect-command.ts

@@ -239,7 +239,10 @@ export abstract class ArchitectCommand<
     );
     const overrides = parseArguments(targetOptions, targetOptionArray, this.logger);
 
-    if (overrides['--']) {
+    const allowAdditionalProperties = typeof builderDesc.optionSchema === 'object'
+      && builderDesc.optionSchema.additionalProperties;
+
+    if (overrides['--'] && !allowAdditionalProperties) {
       (overrides['--'] || []).forEach(additional => {
         this.logger.fatal(`Unknown option: '${additional.split(/=/)[0]}'`);
       });

tests/legacy-cli/e2e/tests/commands/additional-properties.ts

@@ -0,0 +1,28 @@
+import { createDir, rimraf, writeMultipleFiles } from '../../utils/fs';
+import { execAndWaitForOutputToMatch } from '../../utils/process';
+import { updateJsonFile } from '../../utils/project';
+
+export default async function() {
+  await createDir('example-builder');
+  await writeMultipleFiles({
+    'example-builder/package.json': '{ "builders": "./builders.json" }',
+    'example-builder/schema.json': '{ "$schema": "http://json-schema.org/draft-07/schema", "type": "object", "additionalProperties": true }',
+    'example-builder/builders.json': '{ "$schema": "@angular-devkit/architect/src/builders-schema.json", "builders": { "example": { "implementation": "./example", "schema": "./schema.json" } } }',
+    'example-builder/example.js': 'module.exports.default = require("@angular-devkit/architect").createBuilder((options) => { console.log(options); return { success: true }; });',
+  });
+
+  await updateJsonFile('angular.json', json => {
+    const appArchitect = json.projects['test-project'].architect;
+    appArchitect.example = {
+      builder: './example-builder:example',
+    };
+  });
+
+  await execAndWaitForOutputToMatch(
+    'ng',
+    ['run', 'test-project:example', '--additional', 'property'],
+    /'{ '--': \[ '--additional', 'property' \] }'/,
+  );
+
+  await rimraf('example-builder');
+}