feat(dev-infra): integrate merge script into ng-dev cli (#37138)

Integrates the merge script into the `ng-dev` CLI. The goal is that
caretakers can run the same command across repositories to merge a pull
request. The command is as followed: `yarn ng-dev pr merge <number>`.

PR Close #37138

dev-infra/pr/BUILD.bazel

@@ -2,20 +2,12 @@ load("@npm_bazel_typescript//:index.bzl", "ts_library")
 
 ts_library(
     name = "pr",
-    srcs = glob([
-        "*.ts",
-    ]),
+    srcs = ["cli.ts"],
     module_name = "@angular/dev-infra-private/pr",
     visibility = ["//dev-infra:__subpackages__"],
     deps = [
-        "//dev-infra/utils",
-        "@npm//@types/cli-progress",
-        "@npm//@types/node",
-        "@npm//@types/shelljs",
+        "//dev-infra/pr/discover-new-conflicts",
+        "//dev-infra/pr/merge",
         "@npm//@types/yargs",
-        "@npm//cli-progress",
-        "@npm//shelljs",
-        "@npm//typed-graphqlify",
-        "@npm//yargs",
     ],
 )

dev-infra/pr/cli.ts

@@ -7,39 +7,20 @@
  */
 
 import * as yargs from 'yargs';
-import {discoverNewConflictsForPr} from './discover-new-conflicts';
 
-/** A Date object 30 days ago. */
-const THIRTY_DAYS_AGO = (() => {
-  const date = new Date();
-  // Set the hours, minutes and seconds to 0 to only consider date.
-  date.setHours(0, 0, 0, 0);
-  // Set the date to 30 days in the past.
-  date.setDate(date.getDate() - 30);
-  return date;
-})();
+import {buildDiscoverNewConflictsCommand, handleDiscoverNewConflictsCommand} from './discover-new-conflicts/cli';
+import {buildMergeCommand, handleMergeCommand} from './merge/cli';
 
-/** Build the parser for the pr commands. */
+/** Build the parser for pull request commands. */
 export function buildPrParser(localYargs: yargs.Argv) {
-  return localYargs.help().strict().demandCommand().command(
-      'discover-new-conflicts <pr>',
-      'Check if a pending PR causes new conflicts for other pending PRs',
-      args => {
-        return args.option('date', {
-          description: 'Only consider PRs updated since provided date',
-          defaultDescription: '30 days ago',
-          coerce: Date.parse,
-          default: THIRTY_DAYS_AGO,
-        });
-      },
-      ({pr, date}) => {
-        // If a provided date is not able to be parsed, yargs provides it as NaN.
-        if (isNaN(date)) {
-          console.error('Unable to parse the value provided via --date flag');
-          process.exit(1);
-        }
-        discoverNewConflictsForPr(pr, date);
-      });
+  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',
+          buildDiscoverNewConflictsCommand, handleDiscoverNewConflictsCommand)
 }
 
 if (require.main === module) {

dev-infra/pr/discover-new-conflicts/BUILD.bazel

@@ -0,0 +1,19 @@
+load("@npm_bazel_typescript//:index.bzl", "ts_library")
+
+ts_library(
+    name = "discover-new-conflicts",
+    srcs = [
+        "cli.ts",
+        "index.ts",
+    ],
+    module_name = "@angular/dev-infra-private/pr/discover-new-conflicts",
+    visibility = ["//dev-infra:__subpackages__"],
+    deps = [
+        "//dev-infra/utils",
+        "@npm//@types/cli-progress",
+        "@npm//@types/node",
+        "@npm//@types/shelljs",
+        "@npm//@types/yargs",
+        "@npm//typed-graphqlify",
+    ],
+)

dev-infra/pr/discover-new-conflicts/cli.ts

@@ -0,0 +1,33 @@
+import {Arguments, Argv} from 'yargs';
+
+import {discoverNewConflictsForPr} from './index';
+
+/** Builds the discover-new-conflicts pull request command. */
+export function buildDiscoverNewConflictsCommand(yargs: Argv) {
+  return yargs.option('date', {
+    description: 'Only consider PRs updated since provided date',
+    defaultDescription: '30 days ago',
+    coerce: Date.parse,
+    default: getThirtyDaysAgoDate,
+  });
+}
+
+/** Handles the discover-new-conflicts pull request command. */
+export async function handleDiscoverNewConflictsCommand({prNumber, date}: Arguments) {
+  // If a provided date is not able to be parsed, yargs provides it as NaN.
+  if (isNaN(date)) {
+    console.error('Unable to parse the value provided via --date flag');
+    process.exit(1);
+  }
+  await discoverNewConflictsForPr(prNumber, date);
+}
+
+/** Gets a date object 30 days ago from today. */
+function getThirtyDaysAgoDate(): Date {
+  const date = new Date();
+  // Set the hours, minutes and seconds to 0 to only consider date.
+  date.setHours(0, 0, 0, 0);
+  // Set the date to 30 days in the past.
+  date.setDate(date.getDate() - 30);
+  return date;
+}

dev-infra/pr/discover-new-conflicts/index.ts

@@ -9,10 +9,10 @@
 import {Bar} from 'cli-progress';
 import {types as graphQLTypes} from 'typed-graphqlify';
 
-import {getConfig, NgDevConfig} from '../utils/config';
-import {getCurrentBranch, hasLocalChanges} from '../utils/git';
-import {getPendingPrs} from '../utils/github';
-import {exec} from '../utils/shelljs';
+import {getConfig, NgDevConfig} from '../../utils/config';
+import {getCurrentBranch, hasLocalChanges} from '../../utils/git';
+import {getPendingPrs} from '../../utils/github';
+import {exec} from '../../utils/shelljs';
 
 
 /* GraphQL schema for the response body for each pending PR. */
@@ -67,8 +67,6 @@ export async function discoverNewConflictsForPr(
   const progressBar = new Bar({format: `[{bar}] ETA: {eta}s | {value}/{total}`});
   /* PRs which were found to be conflicting. */
   const conflicts: Array<PullRequest> = [];
-  /* String version of the updatedAfter value, for logging. */
-  const updatedAfterString = new Date(updatedAfter).toLocaleDateString();
 
   console.info(`Requesting pending PRs from Github`);
   /** List of PRs from github currently known as mergable. */

dev-infra/pr/merge/BUILD.bazel

@@ -0,0 +1,17 @@
+load("@npm_bazel_typescript//:index.bzl", "ts_library")
+
+ts_library(
+    name = "merge",
+    srcs = glob(["**/*.ts"]),
+    module_name = "@angular/dev-infra-private/pr/merge",
+    visibility = ["//dev-infra:__subpackages__"],
+    deps = [
+        "//dev-infra/commit-message",
+        "//dev-infra/utils",
+        "@npm//@octokit/rest",
+        "@npm//@types/inquirer",
+        "@npm//@types/node",
+        "@npm//@types/yargs",
+        "@npm//chalk",
+    ],
+)

dev-infra/pr/merge/cli.ts

@@ -0,0 +1,33 @@
+/**
+ * @license
+ * Copyright Google LLC All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+import chalk from 'chalk';
+import {Arguments, Argv} from 'yargs';
+import {GITHUB_TOKEN_GENERATE_URL, mergePullRequest} from './index';
+
+/** Builds the options for the merge command. */
+export function buildMergeCommand(yargs: Argv) {
+  return yargs.help().strict().option('github-token', {
+    type: 'string',
+    description: 'Github token. If not set, token is retrieved from the environment variables.'
+  })
+}
+
+/** Handles the merge command. i.e. performs the merge of a specified pull request. */
+export async function handleMergeCommand(args: Arguments) {
+  const githubToken = args.githubToken || process.env.GITHUB_TOKEN || process.env.TOKEN;
+  if (!githubToken) {
+    console.error(
+        chalk.red('No Github token set. Please set the `GITHUB_TOKEN` environment variable.'));
+    console.error(chalk.red('Alternatively, pass the `--github-token` command line flag.'));
+    console.error(chalk.yellow(`You can generate a token here: ${GITHUB_TOKEN_GENERATE_URL}`));
+    process.exit(1);
+  }
+
+  await mergePullRequest(args.prNumber, githubToken);
+}

dev-infra/pr/merge/config.ts

@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {getAngularDevConfig} from '../../utils/config';
+import {getConfig, NgDevConfig} from '../../utils/config';
 
 import {GithubApiMergeStrategyConfig} from './strategies/api-merge';
 
@@ -31,10 +31,30 @@ export interface TargetLabel {
   branches: string[]|((githubTargetBranch: string) => string[]);
 }
 
+/** Describes the remote used for merging pull requests. */
+export interface MergeRemote {
+  /** Owner name of the repository. */
+  owner: string;
+  /** Name of the repository. */
+  name: string;
+  /** Whether SSH should be used for merging pull requests. */
+  useSsh?: boolean
+}
+
+/**
+ * Configuration for the merge script with all remote options specified. The
+ * default `MergeConfig` has does not require any of these options as defaults
+ * are provided by the common dev-infra github configuration.
+ */
+export type MergeConfigWithRemote = MergeConfig&{remote: MergeRemote};
+
 /** Configuration for the merge script. */
 export interface MergeConfig {
-  /** Configuration for the upstream repository. */
-  repository: {user: string; name: string; useSsh?: boolean};
+  /**
+   * Configuration for the upstream remote. All of these options are optional as
+   * defaults are provided by the common dev-infra github configuration.
+   */
+  remote?: Partial<MergeRemote>;
   /** List of target labels. */
   labels: TargetLabel[];
   /** Required base commits for given branches. */
@@ -54,34 +74,56 @@ export interface MergeConfig {
   githubApiMerge: false|GithubApiMergeStrategyConfig;
 }
 
+/**
+ * Configuration of the merge script in the dev-infra configuration. Note that the
+ * merge configuration is retrieved lazily as usually these configurations rely
+ * on branch name computations. We don't want to run these immediately whenever
+ * the dev-infra configuration is loaded as that could slow-down other commands.
+ */
+export type DevInfraMergeConfig = NgDevConfig<{'merge': () => MergeConfig}>;
+
 /** Loads and validates the merge configuration. */
-export function loadAndValidateConfig(): {config?: MergeConfig, errors?: string[]} {
-  const config = getAngularDevConfig<'merge', MergeConfig>().merge;
-  if (config === undefined) {
+export function loadAndValidateConfig(): {config?: MergeConfigWithRemote, errors?: string[]} {
+  const config: Partial<DevInfraMergeConfig> = getConfig();
+
+  if (config.merge === undefined) {
     return {
       errors: ['No merge configuration found. Set the `merge` configuration.']
     }
   }
-  const errors = validateConfig(config);
+
+  if (typeof config.merge !== 'function') {
+    return {
+      errors: ['Expected merge configuration to be defined lazily through a function.']
+    }
+  }
+
+  const mergeConfig = config.merge();
+  const errors = validateMergeConfig(mergeConfig);
+
   if (errors.length) {
     return {errors};
   }
-  return {config};
+
+  if (mergeConfig.remote) {
+    mergeConfig.remote = {...config.github, ...mergeConfig.remote};
+  } else {
+    mergeConfig.remote = config.github;
+  }
+
+  // We always set the `remote` option, so we can safely cast the
+  // config to `MergeConfigWithRemote`.
+  return {config: mergeConfig as MergeConfigWithRemote};
 }
 
 /** Validates the specified configuration. Returns a list of failure messages. */
-function validateConfig(config: MergeConfig): string[] {
+function validateMergeConfig(config: Partial<MergeConfig>): string[] {
   const errors: string[] = [];
   if (!config.labels) {
     errors.push('No label configuration.');
   } else if (!Array.isArray(config.labels)) {
     errors.push('Label configuration needs to be an array.');
   }
-  if (!config.repository) {
-    errors.push('No repository is configured.');
-  } else if (!config.repository.user || !config.repository.name) {
-    errors.push('Repository configuration needs to specify a `user` and repository `name`.');
-  }
   if (!config.claSignedLabel) {
     errors.push('No CLA signed label configured.');
   }

dev-infra/pr/merge/git.ts

@@ -8,7 +8,7 @@
 
 import * as Octokit from '@octokit/rest';
 import {spawnSync, SpawnSyncOptions, SpawnSyncReturns} from 'child_process';
-import {MergeConfig} from './config';
+import {MergeConfigWithRemote} from './config';
 
 /** Error for failed Github API requests. */
 export class GithubApiRequestError extends Error {
@@ -28,14 +28,15 @@ export class GitCommandError extends Error {
 }
 
 export class GitClient {
-  /** Short-hand for accessing the repository configuration. */
-  repoConfig = this._config.repository;
-  /** Octokit request parameters object for targeting the configured repository. */
-  repoParams = {owner: this.repoConfig.user, repo: this.repoConfig.name};
+  /** Short-hand for accessing the remote configuration. */
+  remoteConfig = this._config.remote;
+  /** Octokit request parameters object for targeting the configured remote. */
+  remoteParams = {owner: this.remoteConfig.owner, repo: this.remoteConfig.name};
   /** URL that resolves to the configured repository. */
-  repoGitUrl = this.repoConfig.useSsh ?
-      `git@github.com:${this.repoConfig.user}/${this.repoConfig.name}.git` :
-      `https://${this._githubToken}@github.com/${this.repoConfig.user}/${this.repoConfig.name}.git`;
+  repoGitUrl = this.remoteConfig.useSsh ?
+      `git@github.com:${this.remoteConfig.owner}/${this.remoteConfig.name}.git` :
+      `https://${this._githubToken}@github.com/${this.remoteConfig.owner}/${
+          this.remoteConfig.name}.git`;
   /** Instance of the authenticated Github octokit API. */
   api: Octokit;
 
@@ -43,7 +44,8 @@ export class GitClient {
   private _tokenRegex = new RegExp(this._githubToken, 'g');
 
   constructor(
-      private _projectRoot: string, private _githubToken: string, private _config: MergeConfig) {
+      private _projectRoot: string, private _githubToken: string,
+      private _config: MergeConfigWithRemote) {
     this.api = new Octokit({auth: _githubToken});
     this.api.hook.error('request', error => {
       // Wrap API errors in a known error class. This allows us to

dev-infra/pr/merge/index.ts

@@ -6,31 +6,45 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {MergeResult, MergeStatus, PullRequestMergeTask} from './task';
-import {GithubApiRequestError} from './git';
 import chalk from 'chalk';
-import {promptConfirm} from './console';
-import {loadAndValidateConfig} from './config';
+
 import {getRepoBaseDir} from '../../utils/config';
+import {promptConfirm} from '../../utils/console';
+
+import {loadAndValidateConfig, MergeConfigWithRemote} from './config';
+import {GithubApiRequestError} from './git';
+import {MergeResult, MergeStatus, PullRequestMergeTask} from './task';
 
 /** URL to the Github page where personal access tokens can be generated. */
 export const GITHUB_TOKEN_GENERATE_URL = `https://github.com/settings/tokens`;
 
 
 /**
- * Entry-point for the merge script CLI. The script can be used to merge individual pull requests
- * into branches based on the `PR target` labels that have been set in a configuration. The script
- * aims to reduce the manual work that needs to be performed to cherry-pick a PR into multiple
- * branches based on a target label.
+ * Merges a given pull request based on labels configured in the given merge configuration.
+ * Pull requests can be merged with different strategies such as the Github API merge
+ * strategy, or the local autosquash strategy. Either strategy has benefits and downsides.
+ * More information on these strategies can be found in their dedicated strategy classes.
+ *
+ * See {@link GithubApiMergeStrategy} and {@link AutosquashMergeStrategy}
+ *
+ * @param prNumber Number of the pull request that should be merged.
+ * @param githubToken Github token used for merging (i.e. fetching and pushing)
+ * @param projectRoot Path to the local Git project that is used for merging.
+ * @param config Configuration for merging pull requests.
  */
-export async function mergePullRequest(prNumber: number, githubToken: string) {
-  const projectRoot = getRepoBaseDir();
-  const {config, errors} = loadAndValidateConfig();
-
-  if (errors) {
-    console.error(chalk.red('Invalid configuration:'));
-    errors.forEach(desc => console.error(chalk.yellow(`  -  ${desc}`)));
-    process.exit(1);
+export async function mergePullRequest(
+    prNumber: number, githubToken: string, projectRoot: string = getRepoBaseDir(),
+    config?: MergeConfigWithRemote) {
+  // If no explicit configuration has been specified, we load and validate
+  // the configuration from the shared dev-infra configuration.
+  if (config === undefined) {
+    const {config: _config, errors} = loadAndValidateConfig();
+    if (errors) {
+      console.error(chalk.red('Invalid configuration:'));
+      errors.forEach(desc => console.error(chalk.yellow(`  -  ${desc}`)));
+      process.exit(1);
+    }
+    config = _config!;
   }
 
   const api = new PullRequestMergeTask(projectRoot, config, githubToken);

dev-infra/pr/merge/pull-request.ts

@@ -62,7 +62,7 @@ export async function loadAndValidatePullRequest(
   }
 
   const {data: {state}} =
-      await git.api.repos.getCombinedStatusForRef({...git.repoParams, ref: prData.head.sha});
+      await git.api.repos.getCombinedStatusForRef({...git.remoteParams, ref: prData.head.sha});
 
   if (state === 'failure' && !ignoreNonFatalFailures) {
     return PullRequestFailure.failingCiJobs();
@@ -93,7 +93,7 @@ export async function loadAndValidatePullRequest(
 async function fetchPullRequestFromGithub(
     git: GitClient, prNumber: number): Promise<Octokit.PullsGetResponse|null> {
   try {
-    const result = await git.api.pulls.get({...git.repoParams, pull_number: prNumber});
+    const result = await git.api.pulls.get({...git.remoteParams, pull_number: prNumber});
     return result.data;
   } catch (e) {
     // If the pull request could not be found, we want to return `null` so

dev-infra/pr/merge/strategies/api-merge.ts

@@ -77,7 +77,7 @@ export class GithubApiMergeStrategy extends MergeStrategy {
     const mergeOptions: PullsMergeParams = {
       pull_number: prNumber,
       merge_method: method,
-      ...this.git.repoParams,
+      ...this.git.remoteParams,
     };
 
     if (needsCommitMessageFixup) {
@@ -190,7 +190,7 @@ export class GithubApiMergeStrategy extends MergeStrategy {
   /** Gets all commit messages of commits in the pull request. */
   private async _getPullRequestCommitMessages({prNumber}: PullRequest) {
     const request = this.git.api.pulls.listCommits.endpoint.merge(
-        {...this.git.repoParams, pull_number: prNumber});
+        {...this.git.remoteParams, pull_number: prNumber});
     const allCommits: PullsListCommitsResponse = await this.git.api.paginate(request);
     return allCommits.map(({commit}) => commit.message);
   }

dev-infra/pr/merge/task.ts

@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {MergeConfig} from './config';
+import {MergeConfigWithRemote} from './config';
 import {PullRequestFailure} from './failures';
 import {GitClient, GitCommandError} from './git';
 import {isPullRequest, loadAndValidatePullRequest,} from './pull-request';
@@ -39,7 +39,8 @@ export class PullRequestMergeTask {
   git = new GitClient(this.projectRoot, this._githubToken, this.config);
 
   constructor(
-      public projectRoot: string, public config: MergeConfig, private _githubToken: string) {}
+      public projectRoot: string, public config: MergeConfigWithRemote,
+      private _githubToken: string) {}
 
   /**
    * Merges the given pull request and pushes it upstream.

dev-infra/utils/BUILD.bazel

@@ -7,6 +7,7 @@ ts_library(
     visibility = ["//dev-infra:__subpackages__"],
     deps = [
         "@npm//@octokit/graphql",
+        "@npm//@types/inquirer",
         "@npm//@types/node",
         "@npm//@types/shelljs",
         "@npm//shelljs",

dev-infra/utils/config.ts

@@ -9,13 +9,20 @@
 import {join} from 'path';
 import {exec} from 'shelljs';
 
+/**
+ * Describes the Github configuration for dev-infra. This configuration is
+ * used for API requests, determining the upstream remote, etc.
+ */
+export interface GithubConfig {
+  /** Owner name of the repository. */
+  owner: string;
+  /** Name of the repository. */
+  name: string;
+}
+
 /** The common configuration for ng-dev. */
 type CommonConfig = {
-  /* Github repository configuration used for API Requests, determining upstream remote, etc. */
-  github: {
-    owner: string,
-    name: string,
-  }
+  github: GithubConfig
 };
 
 /**