feat(dev-infra): support --no-branch-prompt to suppress the merge tool branch target confirmation (#40528)

Add support for a `--no-branch-prompt` flag for the `ng-dev pr merge` tool.  This
flag enables suppression of the confirmation prompt for which branches the specified
PR will merge into.

PR Close #40528

dev-infra/pr/cli.ts

@@ -11,7 +11,7 @@ import * as yargs from 'yargs';
 import {CheckTargetBranchesModule} from './check-target-branches/cli';
 import {CheckoutCommandModule} from './checkout/cli';
 import {buildDiscoverNewConflictsCommand, handleDiscoverNewConflictsCommand} from './discover-new-conflicts/cli';
-import {buildMergeCommand, handleMergeCommand} from './merge/cli';
+import {MergeCommandModule} from './merge/cli';
 import {buildRebaseCommand, handleRebaseCommand} from './rebase/cli';
 
 /** Build the parser for pull request commands. */
@@ -19,7 +19,6 @@ export function buildPrParser(localYargs: yargs.Argv) {
   return localYargs.help()
       .strict()
       .demandCommand()
-      .command('merge <pr-number>', 'Merge pull requests', buildMergeCommand, handleMergeCommand)
       .command(
           'discover-new-conflicts <pr-number>',
           'Check if a pending PR causes new conflicts for other pending PRs',
@@ -27,6 +26,7 @@ export function buildPrParser(localYargs: yargs.Argv) {
       .command(
           'rebase <pr-number>', 'Rebase a pending PR and push the rebased commits back to Github',
           buildRebaseCommand, handleRebaseCommand)
+      .command(MergeCommandModule)
       .command(CheckoutCommandModule)
       .command(CheckTargetBranchesModule);
 }

dev-infra/pr/merge/cli.ts

@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {Arguments, Argv} from 'yargs';
+import {Arguments, Argv, CommandModule} from 'yargs';
 
 import {addGithubTokenOption} from '../../utils/git/github-yargs';
 
@@ -15,17 +15,36 @@ import {mergePullRequest} from './index';
 /** The options available to the merge command via CLI. */
 export interface MergeCommandOptions {
   githubToken: string;
-  'pr-number': number;
+  pr: number;
+  branchPrompt: boolean;
 }
 
-/** Builds the options for the merge command. */
-export function buildMergeCommand(yargs: Argv): Argv<MergeCommandOptions> {
-  return addGithubTokenOption(yargs).help().strict().positional(
-      'pr-number', {demandOption: true, type: 'number'});
+/** Builds the command. */
+function builder(yargs: Argv) {
+  return addGithubTokenOption(yargs)
+      .help()
+      .strict()
+      .positional('pr', {
+        demandOption: true,
+        type: 'number',
+        description: 'The PR to be merged.',
+      })
+      .option('branch-prompt' as 'branchPrompt', {
+        type: 'boolean',
+        default: true,
+        description: 'Whether to prompt to confirm the branches a PR will merge into.',
+      });
 }
 
-/** Handles the merge command. i.e. performs the merge of a specified pull request. */
-export async function handleMergeCommand(
-    {'pr-number': pr, githubToken}: Arguments<MergeCommandOptions>) {
-  await mergePullRequest(pr, githubToken);
+/** Handles the command. */
+async function handler({pr, githubToken, branchPrompt}: Arguments<MergeCommandOptions>) {
+  await mergePullRequest(pr, githubToken, {branchPrompt});
 }
+
+/** yargs command module describing the command.  */
+export const MergeCommandModule: CommandModule<{}, MergeCommandOptions> = {
+  handler,
+  builder,
+  command: 'merge <pr>',
+  describe: 'Merge a PR into its targeted branches.',
+};

dev-infra/pr/merge/index.ts

@@ -14,7 +14,7 @@ import {GITHUB_TOKEN_GENERATE_URL} from '../../utils/git/github-urls';
 import {GitClient} from '../../utils/git/index';
 
 import {loadAndValidateConfig, MergeConfigWithRemote} from './config';
-import {MergeResult, MergeStatus, PullRequestMergeTask} from './task';
+import {MergeResult, MergeStatus, PullRequestMergeTask, PullRequestMergeTaskFlags} from './task';
 
 /**
  * Merges a given pull request based on labels configured in the given merge configuration.
@@ -30,13 +30,12 @@ import {MergeResult, MergeStatus, PullRequestMergeTask} from './task';
  * @param config Configuration for merging pull requests.
  */
 export async function mergePullRequest(
-    prNumber: number, githubToken: string, projectRoot: string = getRepoBaseDir(),
-    config?: MergeConfigWithRemote) {
+    prNumber: number, githubToken: string, flags: PullRequestMergeTaskFlags) {
   // Set the environment variable to skip all git commit hooks triggered by husky. We are unable to
   // rely on `--no-verify` as some hooks still run, notably the `prepare-commit-msg` hook.
   process.env['HUSKY'] = '0';
 
-  const api = await createPullRequestMergeTask(githubToken, projectRoot, config);
+  const api = await createPullRequestMergeTask(githubToken, flags);
 
   // Perform the merge. Force mode can be activated through a command line flag.
   // Alternatively, if the merge fails with non-fatal failures, the script
@@ -128,13 +127,8 @@ export async function mergePullRequest(
  * and optional explicit configuration. An explicit configuration can be specified
  * when the merge script is used outside of a `ng-dev` configured repository.
  */
-async function createPullRequestMergeTask(
-    githubToken: string, projectRoot: string, explicitConfig?: MergeConfigWithRemote) {
-  if (explicitConfig !== undefined) {
-    const git = new GitClient(githubToken, {github: explicitConfig.remote}, projectRoot);
-    return new PullRequestMergeTask(explicitConfig, git);
-  }
-
+async function createPullRequestMergeTask(githubToken: string, flags: PullRequestMergeTaskFlags) {
+  const projectRoot = getRepoBaseDir();
   const devInfraConfig = getConfig();
   const git = new GitClient(githubToken, devInfraConfig, projectRoot);
   const {config, errors} = await loadAndValidateConfig(devInfraConfig, git.github);
@@ -150,5 +144,5 @@ async function createPullRequestMergeTask(
   config!.remote = devInfraConfig.github;
   // We can cast this to a merge config with remote because we always set the
   // remote above.
-  return new PullRequestMergeTask(config! as MergeConfigWithRemote, git);
+  return new PullRequestMergeTask(config! as MergeConfigWithRemote, git, flags);
 }

dev-infra/pr/merge/task.ts

@@ -34,13 +34,28 @@ export interface MergeResult {
   failure?: PullRequestFailure;
 }
 
+export interface PullRequestMergeTaskFlags {
+  branchPrompt: boolean;
+}
+
+const defaultPullRequestMergeTaskFlags: PullRequestMergeTaskFlags = {
+  branchPrompt: true,
+};
+
 /**
  * Class that accepts a merge script configuration and Github token. It provides
  * a programmatic interface for merging multiple pull requests based on their
  * labels that have been resolved through the merge script configuration.
  */
 export class PullRequestMergeTask {
-  constructor(public config: MergeConfigWithRemote, public git: GitClient) {}
+  private flags: PullRequestMergeTaskFlags;
+
+  constructor(
+      public config: MergeConfigWithRemote, public git: GitClient,
+      flags: Partial<PullRequestMergeTaskFlags>) {
+    // Update flags property with the provided flags values as patches to the default flag values.
+    this.flags = {...defaultPullRequestMergeTaskFlags, ...flags};
+  }
 
   /**
    * Merges the given pull request and pushes it upstream.
@@ -79,7 +94,8 @@ export class PullRequestMergeTask {
     }
 
 
-    if (!await promptConfirm(getTargettedBranchesConfirmationPromptMessage(pullRequest))) {
+    if (this.flags.branchPrompt &&
+        !await promptConfirm(getTargettedBranchesConfirmationPromptMessage(pullRequest))) {
       return {status: MergeStatus.USER_ABORTED};
     }