feat(ng-dev): update renovate.json baseBranches when creating a new branch

Adds support for automatically modifying `renovate.json` to include newly created branches in the `baseBranches` array, when `updateRenovateConfig` is enabled.

Author: alan-agius4

ng-dev/release/publish/actions.ts

@@ -19,7 +19,7 @@ import {
   getListCommitsInBranchUrl,
   getRepositoryGitUrl,
 } from '../../utils/git/github-urls.js';
-import {green, Log} from '../../utils/logging.js';
+import {green, Log, yellow} from '../../utils/logging.js';
 import {Spinner} from '../../utils/spinner.js';
 import {BuiltPackage, BuiltPackageWithInfo, ReleaseConfig} from '../config/index.js';
 import {ReleaseNotes, workspaceRelativeChangelogPath} from '../notes/release-notes.js';
@@ -140,6 +140,36 @@ export abstract class ReleaseAction {
     }
   }
 
+  /**
+   * Updates the `renovate.json` configuration file to include a new base branch.
+   *
+   * This is used when `rulesJsInteropMode` is enabled to ensure the Renovate
+   * tool considers both the main branch and a new feature or update branch.
+   *
+   * @param newBranchName - The name of the new branch to add to the base branches list.
+   * @returns A promise that resolves to an string containing the path to the modified `renovate.json` file,
+   *          or null if config updating is disabled.
+   */
+  protected async updateRenovateConfig(newBranchName: string): Promise<string | null> {
+    const spinner = new Spinner('Updating Renovate config');
+    const renovateConfigPath = path.join(this.projectDir, 'renovate.json');
+    const config = await fs.readFile(renovateConfigPath, 'utf-8');
+    const configJson = JSON.parse(config);
+    if (configJson.baseBranches?.length !== 2) {
+      spinner.success(
+        yellow('Skipped updating Renovate config: "baseBranches" must contain exactly 2 branches.'),
+      );
+
+      return null;
+    }
+
+    configJson.baseBranches = ['main', newBranchName];
+    await fs.writeFile(renovateConfigPath, JSON.stringify(configJson, undefined, 2));
+    spinner.success(green(' Updated Renovate config'));
+
+    return renovateConfigPath;
+  }
+
   /*
    * Get the modified Aspect lock files if `rulesJsInteropMode` is enabled.
    */

ng-dev/release/publish/actions/shared/branch-off-next-branch.ts

@@ -139,11 +139,17 @@ export abstract class BranchOffNextBranchBaseAction extends CutNpmNextPrerelease
 
     // Create an individual commit for the next version bump. The changelog should go into
     // a separate commit that makes it clear where the changelog is cherry-picked from.
-    await this.createCommit(bumpCommitMessage, [
+    const filesToCommit: string[] = [
       workspaceRelativePackageJsonPath,
       ...this.getAspectLockFiles(),
-    ]);
+    ];
 
+    const renovateConfigPath = await this.updateRenovateConfig(nextBranch);
+    if (renovateConfigPath) {
+      filesToCommit.push(renovateConfigPath);
+    }
+
+    await this.createCommit(bumpCommitMessage, filesToCommit);
     await this.prependReleaseNotesToChangelog(releaseNotes);
 
     const commitMessage = getReleaseNoteCherryPickCommitMessage(releaseNotes.version);