feat(@angular/cli): allow flags to have deprecation

The feature comes from the "x-deprecated" field in schemas (any schema that is used
to parse arguments), and can be a boolean or a string.

The parser now takes a logger and will warn users when encountering a deprecated
option. These options will also appear in JSON help.

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

@@ -137,7 +137,7 @@ export abstract class ArchitectCommand<
     const builderConf = this._architect.getBuilderConfiguration(targetSpec);
     const builderDesc = await this._architect.getBuilderDescription(builderConf).toPromise();
     const targetOptionArray = await parseJsonSchemaToOptions(this._registry, builderDesc.schema);
-    const overrides = parseArguments(options, targetOptionArray);
+    const overrides = parseArguments(options, targetOptionArray, this.logger);
 
     if (overrides['--']) {
       (overrides['--'] || []).forEach(additional => {

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

@@ -182,7 +182,7 @@ export async function runCommand(
   }
 
   try {
-    const parsedOptions = parser.parseArguments(args, description.options);
+    const parsedOptions = parser.parseArguments(args, description.options, logger);
     Command.setCommandMap(commandMap);
     const command = new description.impl({ workspace }, description, logger);
 

packages/angular/cli/models/interface.ts

@@ -144,6 +144,12 @@ export interface Option {
    */
   positional?: number;
 
+  /**
+   * Deprecation. If this flag is not false a warning will be shown on the console. Either `true`
+   * or a string to show the user as a notice.
+   */
+  deprecated?: boolean | string;
+
   /**
    * Smart default object.
    */

packages/angular/cli/models/parser.ts

@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  *
  */
-import { BaseException, strings } from '@angular-devkit/core';
+import { BaseException, logging, strings } from '@angular-devkit/core';
 import { Arguments, Option, OptionType, Value } from './interface';
 
 
@@ -112,12 +112,15 @@ function _getOptionFromName(name: string, options: Option[]): Option | undefined
 function _assignOption(
   arg: string,
   args: string[],
-  options: Option[],
-  parsedOptions: Arguments,
-  _positionals: string[],
-  leftovers: string[],
-  ignored: string[],
-  errors: string[],
+  { options, parsedOptions, leftovers, ignored, errors, deprecations }: {
+    options: Option[],
+    parsedOptions: Arguments,
+    positionals: string[],
+    leftovers: string[],
+    ignored: string[],
+    errors: string[],
+    deprecations: string[],
+  },
 ) {
   const from = arg.startsWith('--') ? 2 : 1;
   let key = arg.substr(from);
@@ -185,6 +188,11 @@ function _assignOption(
     const v = _coerce(value, option, parsedOptions[option.name]);
     if (v !== undefined) {
       parsedOptions[option.name] = v;
+
+      if (option.deprecated !== undefined && option.deprecated !== false) {
+        deprecations.push(`Option ${JSON.stringify(option.name)} is deprecated${
+            typeof option.deprecated == 'string' ? ': ' + option.deprecated : ''}.`);
+      }
     } else {
       let error = `Argument ${key} could not be parsed using value ${JSON.stringify(value)}.`;
       if (option.enum) {
@@ -258,9 +266,14 @@ export function parseFreeFormArguments(args: string[]): Arguments {
  *
  * @param args The argument array to parse.
  * @param options List of supported options. {@see Option}.
+ * @param logger Logger to use to warn users.
  * @returns An object that contains a property per option.
  */
-export function parseArguments(args: string[], options: Option[] | null): Arguments {
+export function parseArguments(
+  args: string[],
+  options: Option[] | null,
+  logger?: logging.Logger,
+): Arguments {
   if (options === null) {
     options = [];
   }
@@ -271,6 +284,9 @@ export function parseArguments(args: string[], options: Option[] | null): Argume
 
   const ignored: string[] = [];
   const errors: string[] = [];
+  const deprecations: string[] = [];
+
+  const state = { options, parsedOptions, positionals, leftovers, ignored, errors, deprecations };
 
   for (let arg = args.shift(); arg !== undefined; arg = args.shift()) {
     if (arg == '--') {
@@ -280,7 +296,7 @@ export function parseArguments(args: string[], options: Option[] | null): Argume
     }
 
     if (arg.startsWith('--')) {
-      _assignOption(arg, args, options, parsedOptions, positionals, leftovers, ignored, errors);
+      _assignOption(arg, args, state);
     } else if (arg.startsWith('-')) {
       // Argument is of form -abcdef.  Starts at 1 because we skip the `-`.
       for (let i = 1; i < arg.length; i++) {
@@ -288,14 +304,14 @@ export function parseArguments(args: string[], options: Option[] | null): Argume
         // If the next character is an '=', treat it as a long flag.
         if (arg[i + 1] == '=') {
           const f = '-' + flag + arg.slice(i + 1);
-          _assignOption(f, args, options, parsedOptions, positionals, leftovers, ignored, errors);
+          _assignOption(f, args, state);
           break;
         }
         // Treat the last flag as `--a` (as if full flag but just one letter). We do this in
         // the loop because it saves us a check to see if the arg is just `-`.
         if (i == arg.length - 1) {
           const arg = '-' + flag;
-          _assignOption(arg, args, options, parsedOptions, positionals, leftovers, ignored, errors);
+          _assignOption(arg, args, state);
         } else {
           const maybeOption = _getOptionFromName(flag, options);
           if (maybeOption) {
@@ -352,6 +368,10 @@ export function parseArguments(args: string[], options: Option[] | null): Argume
     parsedOptions['--'] = [...positionals, ...leftovers];
   }
 
+  if (deprecations.length > 0 && logger) {
+    deprecations.forEach(message => logger.warn(message));
+  }
+
   if (errors.length > 0) {
     throw new ParseArgumentException(errors, parsedOptions, ignored);
   }

packages/angular/cli/models/parser_spec.ts

@@ -6,6 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  *
  */
+import { logging } from '@angular-devkit/core';
 import { Arguments, Option, OptionType } from './interface';
 import { ParseArgumentException, parseArguments } from './parser';
 
@@ -157,4 +158,41 @@ describe('parseArguments', () => {
       }
     });
   });
+
+  it('handles deprecation', () => {
+    const options = [
+      { name: 'bool', aliases: [], type: OptionType.Boolean, description: '' },
+      { name: 'depr', aliases: [], type: OptionType.Boolean, description: '', deprecated: true },
+      { name: 'deprM', aliases: [], type: OptionType.Boolean, description: '', deprecated: 'ABCD' },
+    ];
+
+    const logger = new logging.Logger('');
+    const messages: string[] = [];
+
+    logger.subscribe(entry => messages.push(entry.message));
+
+    let result = parseArguments(['--bool'], options, logger);
+    expect(result).toEqual({ bool: true });
+    expect(messages).toEqual([]);
+
+    result = parseArguments(['--depr'], options, logger);
+    expect(result).toEqual({ depr: true });
+    expect(messages.length).toEqual(1);
+    expect(messages[0]).toMatch(/\bdepr\b/);
+    messages.shift();
+
+    result = parseArguments(['--depr', '--bool'], options, logger);
+    expect(result).toEqual({ depr: true, bool: true });
+    expect(messages.length).toEqual(1);
+    expect(messages[0]).toMatch(/\bdepr\b/);
+    messages.shift();
+
+    result = parseArguments(['--depr', '--bool', '--deprM'], options, logger);
+    expect(result).toEqual({ depr: true, deprM: true, bool: true });
+    expect(messages.length).toEqual(2);
+    expect(messages[0]).toMatch(/\bdepr\b/);
+    expect(messages[1]).toMatch(/\bdeprM\b/);
+    expect(messages[1]).toMatch(/\bABCD\b/);
+    messages.shift();
+  });
 });

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

@@ -533,7 +533,7 @@ export abstract class SchematicCommand<
     schematicOptions: string[],
     options: Option[] | null,
   ): Promise<Arguments> {
-    return parseArguments(schematicOptions, options);
+    return parseArguments(schematicOptions, options, this.logger);
   }
 
   private async _loadWorkspace() {

packages/angular/cli/utilities/json-schema.ts

@@ -248,6 +248,11 @@ export async function parseJsonSchemaToOptions(
     const visible = current.visible === undefined || current.visible === true;
     const hidden = !!current.hidden || !visible;
 
+    // Deprecated is set only if it's true or a string.
+    const xDeprecated = current['x-deprecated'];
+    const deprecated = (xDeprecated === true || typeof xDeprecated == 'string')
+      ? xDeprecated : undefined;
+
     const option: Option = {
       name,
       description: '' + (current.description === undefined ? '' : current.description),
@@ -258,6 +263,7 @@ export async function parseJsonSchemaToOptions(
       aliases,
       ...format !== undefined ? { format } : {},
       hidden,
+      ...deprecated !== undefined ? { deprecated } : {},
       ...positional !== undefined ? { positional } : {},
     };