feat(github-actions): add auto labeling by path to github labeler action

This adds the ability to add additional labels automatically if a specific path is matched in the pull request commits.

Author: thePunderWoman

.github/local-actions/branch-manager/main.js

@@ -18,6 +18,8 @@ ts_project(
         "//github-actions:utils",
         "//ng-dev/commit-message",
         "//ng-dev/pr/common/labels",
+        "//ng-dev/pr/config",
+        "//ng-dev/utils",
     ],
 )
 
@@ -27,6 +29,9 @@ esbuild_checked_in(
         ":lib",
     ],
     entry_point = "lib/main.ts",
+    external = [
+        "pnpapi",
+    ],
     format = "esm",
     platform = "node",
     target = "node22",

.github/local-actions/labels-sync/main.js

@@ -3,8 +3,10 @@ import {context} from '@actions/github';
 import {Octokit, RestEndpointMethodTypes} from '@octokit/rest';
 import {Commit, parseCommitMessage} from '../../../ng-dev/commit-message/parse.js';
 import {actionLabels, managedLabels, targetLabels} from '../../../ng-dev/pr/common/labels/index.js';
+import {assertValidPullRequestConfig, PullRequestConfig} from '../../../ng-dev/pr/config/index.js';
 import {ANGULAR_ROBOT, getAuthTokenFor, revokeActiveInstallationToken} from '../../utils.js';
 import {ManagedRepositories} from '../../../ng-dev/pr/common/labels/base.js';
+import {getConfig, NgDevConfig} from '../../../ng-dev/utils/config.js';
 
 /** The type of the response data for a the pull request get method on from octokit. */
 type PullRequestGetData = RestEndpointMethodTypes['pulls']['get']['response']['data'];
@@ -17,7 +19,9 @@ class PullRequestLabeling {
     const token = await getAuthTokenFor(ANGULAR_ROBOT);
     const git = new Octokit({auth: token});
     try {
-      const inst = new this(git);
+      const config = await getConfig();
+      assertValidPullRequestConfig(config);
+      const inst = new this(git, config);
       await inst.run();
     } finally {
       await revokeActiveInstallationToken(git);
@@ -32,8 +36,13 @@ class PullRequestLabeling {
   commits: Commit[] = [];
   /** The pull request information from the github API. */
   pullRequestMetadata?: PullRequestGetData;
+  /** The files changed in the pull request */
+  pullRequestFiles?: RestEndpointMethodTypes['pulls']['listFiles']['response']['data'];
 
-  private constructor(private git: Octokit) {}
+  private constructor(
+    private git: Octokit,
+    private config: NgDevConfig<{pullRequest: PullRequestConfig}>,
+  ) {}
 
   /** Run the action, and revoke the installation token on completion. */
   async run() {
@@ -43,6 +52,7 @@ class PullRequestLabeling {
 
     await this.commitMessageBasedLabeling();
     await this.pullRequestMetadataLabeling();
+    await this.pathBasedLabeling();
   }
 
   /**
@@ -107,6 +117,28 @@ class PullRequestLabeling {
     }
   }
 
+  /**
+   * Perform labeling based on the paths of the files in the pull request.
+   */
+  async pathBasedLabeling() {
+    const managedLabelByPath = this.config.pullRequest.managedLabelByPath;
+    if (managedLabelByPath === undefined || this.pullRequestFiles === undefined) {
+      return;
+    }
+
+    for (const [path, labels] of Object.entries(managedLabelByPath)) {
+      for (const file of this.pullRequestFiles) {
+        if (file.filename.startsWith(path)) {
+          for (const label of labels) {
+            if (!this.labels.has(label)) {
+              await this.addLabel(label);
+            }
+          }
+        }
+      }
+    }
+  }
+
   /** Remove the provided label to the pull request. */
   async removeLabel(label: string) {
     const {number: issue_number, owner, repo} = context.issue;
@@ -159,6 +191,10 @@ class PullRequestLabeling {
     await this.git.pulls.get({owner, repo, pull_number: number}).then(({data}) => {
       this.pullRequestMetadata = data;
     });
+
+    await this.git.pulls.listFiles({owner, repo, pull_number: number}).then(({data}) => {
+      this.pullRequestFiles = data;
+    });
   }
 }