fix(github-actions): resolve pending mergeability checks on LTS branches

The branch-manager local GitHub Action previously relied on a mocked
minimal configuration which lacked the "release" configuration block.
As a result, validations checking the `TARGET_LTS` target label failed
because they could not determine active LTS branches (which requires
release config settings). This caused LTS PRs to throw an
`InvalidTargetLabelError` and remain in a "pending" status permanently.

This change fixes the issue by dynamically importing the actual repository's
`.ng-dev/config.mjs` configuration after the repository is cloned inside the
local action workspace, merging it with action input overrides and re-caching it.

We also update `setCachedConfig` to support clearing/overwriting the cache
by allowing `null` values.

Author: alan-agius4

.github/local-actions/branch-manager/lib/main.ts

@@ -12,73 +12,77 @@ import {
 import {MergeConflictsFatalError} from '../../../../ng-dev/pr/merge/failures.js';
 import {createPullRequestValidationConfig} from '../../../../ng-dev/pr/common/validation/validation-config.js';
 import {InvalidTargetLabelError} from '../../../../ng-dev/pr/common/targeting/target-label.js';
-import {resolve} from 'path';
+import {
+  assertValidCaretakerConfig,
+  assertValidGithubConfig,
+  setConfig,
+  getConfig,
+} from '../../../../ng-dev/utils/config.js';
+import {assertValidPullRequestConfig} from '../../../../ng-dev/pr/config/index.js';
+import {setTimeout} from 'node:timers/promises';
+import {AuthenticatedGitClient} from '../../../../ng-dev/utils/git/authenticated-git-client.js';
 
 interface CommmitStatus {
   state: 'pending' | 'error' | 'failure' | 'success';
   description: string;
   targetUrl?: string;
 }
 
-/** The context name used for the commmit status applied. */
-const statusContextName = 'mergeability';
-/** The repository name for the pull request. */
-const repo = core.getInput('repo', {required: true, trimWhitespace: true});
-/** The owner of the repository for the pull request. */
-const owner = core.getInput('owner', {required: true, trimWhitespace: true});
-/** The pull request number. */
-const pr = Number(core.getInput('pr', {required: true, trimWhitespace: true}));
-// If the provided pr is not a number, we cannot evaluate the mergeability.
-if (isNaN(pr)) {
-  core.setFailed('The provided pr value was not a number');
-  process.exit();
-}
-/** The token for the angular robot to perform actions in the requested repo. */
-const token = await getAuthTokenFor(ANGULAR_ROBOT, {repo, owner});
-const {
-  /** The ng-dev configuration used for the environment */
-  config,
-  /** The Authenticated Git Client instance. */
-  git,
-} = await setupConfigAndGitClient(token, {owner, repo});
-/** The sha of the latest commit on the pull request, which when provided is what triggered the check. */
-const sha = await (async () => {
-  let sha = core.getInput('sha', {required: false, trimWhitespace: true}) || undefined;
-  if (sha === undefined) {
-    sha = (await git.github.pulls.get({owner, repo, pull_number: pr})).data.head.sha as string;
+async function main() {
+  /** The context name used for the commmit status applied. */
+  const statusContextName = 'mergeability';
+  /** The repository name for the pull request. */
+  const repo = core.getInput('repo', {required: true, trimWhitespace: true});
+  /** The owner of the repository for the pull request. */
+  const owner = core.getInput('owner', {required: true, trimWhitespace: true});
+  /** The pull request number. */
+  const pr = Number(core.getInput('pr', {required: true, trimWhitespace: true}));
+  /** The SHA of the pull request */
+  let sha = core.getInput('sha', {required: false, trimWhitespace: true});
+
+  // If the provided pr is not a number, we cannot evaluate the mergeability.
+  if (isNaN(pr)) {
+    core.setFailed('The provided pr value was not a number');
+    process.exit();
   }
-  return sha;
-})();
-
-/** Set the mergability status on the pull request provided in the environment. */
-async function setMergeabilityStatusOnPullRequest(
-  {state, description, targetUrl}: CommmitStatus,
-  canRetry = true,
-) {
-  try {
-    await git.github.repos.createCommitStatus({
-      owner,
-      repo,
-      sha,
-      context: statusContextName,
-      state,
-      // Status descriptions are limited to 140 characters.
-      description: description.substring(0, 139),
-      target_url: targetUrl,
-    });
-  } catch {
-    if (canRetry) {
-      await new Promise((resolve) => setTimeout(resolve, 5000));
-      await setMergeabilityStatusOnPullRequest({state, description, targetUrl}, false);
+
+  /** Set the mergability status on the pull request provided in the environment. */
+  async function setMergeabilityStatusOnPullRequest(
+    git: AuthenticatedGitClient,
+    sha: string,
+    {state, description, targetUrl}: CommmitStatus,
+    canRetry = true,
+  ) {
+    try {
+      await git.github.repos.createCommitStatus({
+        owner,
+        repo,
+        sha,
+        context: statusContextName,
+        state,
+        // Status descriptions are limited to 140 characters.
+        description: description.substring(0, 139),
+        target_url: targetUrl,
+      });
+    } catch {
+      if (canRetry) {
+        await setTimeout(5_000);
+        await setMergeabilityStatusOnPullRequest(git, sha, {state, description, targetUrl}, false);
+      }
     }
   }
-}
 
-async function main() {
+  const token = await getAuthTokenFor(ANGULAR_ROBOT, {repo, owner});
+
   try {
+    const {git} = await setupConfigAndGitClient(token, {owner, repo});
+    sha ??= (await git.github.pulls.get({owner, repo, pull_number: pr})).data.head.sha;
+
     // This is intentionally not awaited because we are just setting the status to pending, and wanting
     // to continue working.
-    let _unawaitedPromise = setMergeabilityStatusOnPullRequest(
+    void setMergeabilityStatusOnPullRequest(
+      git,
+      sha,
       {
         state: 'pending',
         description: 'Mergability check in progress',
@@ -89,6 +93,16 @@ async function main() {
     // Create a tmp directory to perform checks in and change working to directory to it.
     await cloneRepoIntoTmpLocation({owner, repo});
 
+    // Remove cached config and use the repo config.
+    // TODO(alanagius): this is needed because `setupConfigAndGitClient` uses a dummy config.
+    setConfig(null);
+
+    const config = await getConfig([
+      assertValidGithubConfig,
+      assertValidPullRequestConfig,
+      assertValidCaretakerConfig,
+    ]);
+
     /** The pull request after being retrieved and validated. */
     const pullRequest = await loadAndValidatePullRequest(
       {git, config},
@@ -168,12 +182,12 @@ async function main() {
       }
     })();
 
-    await setMergeabilityStatusOnPullRequest(statusInfo);
+    await setMergeabilityStatusOnPullRequest(git, sha, statusInfo);
   } catch (e: Error | unknown) {
     let state: CommmitStatus['state'] = 'error';
     let description: string;
-    const {runId, repo, serverUrl} = actionContext;
-    const targetUrl = `${serverUrl}/${repo.owner}/${repo.repo}/actions/runs/${runId}`;
+    const {runId, repo: actionRepo, serverUrl} = actionContext;
+    const targetUrl = `${serverUrl}/${actionRepo.owner}/${actionRepo.repo}/actions/runs/${runId}`;
 
     if (e instanceof InvalidTargetLabelError) {
       // For this action, an invalid target label represents that we aren't ready to check the
@@ -185,9 +199,13 @@ async function main() {
     } else {
       description = 'Internal Error, see link for action log';
     }
-    await setMergeabilityStatusOnPullRequest({state, description, targetUrl});
+    await setMergeabilityStatusOnPullRequest(git, sha, {state, description, targetUrl});
     // Re-throw the error so that the action run is set as failing.
     throw e;
+  } finally {
+    if (token !== undefined) {
+      await revokeActiveInstallationToken(token);
+    }
   }
 }
 
@@ -196,6 +214,4 @@ try {
     core.error(e);
     core.setFailed(e.message);
   });
-} finally {
-  await revokeActiveInstallationToken(token);
-}
+} catch {}