ci: Allow manual execution of backport workflow (#26576)

.github/scripts/compute-backport-targets.mjs

@@ -1,6 +1,11 @@
 // Creates backport PR's according to labels on merged PR
 
-import { readPrLabels, resolveRcBranchForTrack, writeGithubOutput } from './github-helpers.mjs';
+import {
+	getPullRequestById,
+	readPrLabels,
+	resolveRcBranchForTrack,
+	writeGithubOutput,
+} from './github-helpers.mjs';
 
 /** @type { Record<string, import('./github-helpers.mjs').ReleaseTrack> } */
 const BACKPORT_BY_TAG_MAP = {
@@ -50,8 +55,38 @@ export function labelsToReleaseCandidateBranches(labels) {
 	return targets;
 }
 
+/**
+ * This script is called in 2 cases:
+ *
+ * 1. When a PR is merged, in which case functions like `readPrLabels` reads PR info from GITHUB_EVENT_PATH
+ * 2. Manually via Workflow Dispatch, where a Pull Request ID is passed as an env parameter
+ *
+ * @returns { Promise<undefined | any> } Pull request object, if ID was provided in env params
+ */
+async function fetchPossiblePullRequestFromEnv() {
+	const pullRequestEnv = process.env.PULL_REQUEST_ID;
+	if (!pullRequestEnv) {
+		// No ID provided, will proceed to read data from GITHUB_EVENT_PATH
+		return undefined;
+	}
+
+	const pullRequestNumber = parseInt(pullRequestEnv);
+	if (isNaN(pullRequestNumber)) {
+		throw new Error(
+			"PULL_REQUEST_ID must be a number. It shouldn't contain any other symbols (#, PR, etc.)",
+		);
+	}
+
+	return await getPullRequestById(pullRequestNumber);
+}
+
+export async function getLabels() {
+	const pullRequest = await fetchPossiblePullRequestFromEnv();
+	return new Set(readPrLabels(pullRequest));
+}
+
 async function main() {
-	const labels = new Set(readPrLabels());
+	const labels = await getLabels();
 	if (!labels || labels.size === 0) {
 		console.log('No labels on PR. Exiting...');
 		return;

.github/scripts/compute-backport-targets.test.mjs

@@ -1,5 +1,6 @@
 import { describe, it, mock, before } from 'node:test';
 import assert from 'node:assert/strict';
+import { readPrLabels } from './github-helpers.mjs';
 
 /**
  * Run these tests by running
@@ -12,9 +13,14 @@ import assert from 'node:assert/strict';
 mock.module('./github-helpers.mjs', {
 	namedExports: {
 		ensureEnvVar: () => {}, // no-op
-		readPrLabels: () => {}, // no-op
+		readPrLabels: readPrLabels,
 		resolveRcBranchForTrack: mockResolveRcBranchForTrack,
 		writeGithubOutput: () => {}, //no-op
+		getPullRequestById: () => {
+			return {
+				labels: ['n8n team', 'Backport to Beta'],
+			};
+		},
 	},
 });
 
@@ -28,9 +34,11 @@ function mockResolveRcBranchForTrack(track) {
 	return undefined;
 }
 
-let labelsToReleaseCandidateBranches;
+let labelsToReleaseCandidateBranches, getLabels;
 before(async () => {
-	({ labelsToReleaseCandidateBranches } = await import('./compute-backport-targets.mjs'));
+	({ labelsToReleaseCandidateBranches, getLabels } = await import(
+		'./compute-backport-targets.mjs'
+	));
 });
 
 describe('Compute backport targets', () => {
@@ -59,4 +67,38 @@ describe('Compute backport targets', () => {
 
 		assert.equal(result.size, 0);
 	});
+
+	it('Should parse labels properly in Pull request context', async () => {
+		process.env.GITHUB_EVENT_PATH = './fixtures/mock-github-event.json';
+		/** @type { Set<string> } */
+		const labels = await getLabels();
+
+		assert.equal(labels.size, 2);
+		assert.ok(labels.has('release'));
+		assert.ok(labels.has('Backport to Stable'));
+	});
+	it('Should parse labels properly in manual workflow context', async () => {
+		process.env.PULL_REQUEST_ID = '123';
+		/** @type { Set<string> } */
+		const labels = await getLabels();
+
+		assert.equal(labels.size, 2);
+		assert.ok(labels.has('n8n team'));
+		assert.ok(labels.has('Backport to Beta'));
+	});
+
+	it('Should throw when passed pull request id with #', async () => {
+		process.env.PULL_REQUEST_ID = '#123';
+		await assert.rejects(getLabels);
+	});
+
+	it('Should not throw when passed pull request id with just a number', async () => {
+		process.env.PULL_REQUEST_ID = '123';
+		await assert.doesNotReject(getLabels);
+	});
+
+	it('Should throw when passed pull request id with other than numbers included', async () => {
+		process.env.PULL_REQUEST_ID = 'abc-123';
+		await assert.rejects(getLabels);
+	});
 });

.github/scripts/fixtures/mock-github-event.json

@@ -0,0 +1,5 @@
+{
+	"pull_request": {
+		"labels": ["release", "Backport to Stable"]
+	}
+}

.github/scripts/github-helpers.mjs

@@ -1,5 +1,7 @@
+import { getOctokit } from '@actions/github';
 import { execFileSync } from 'node:child_process';
 import fs from 'node:fs';
+import path from 'node:path';
 import semver from 'semver';
 
 export const RELEASE_TRACKS = /** @type { const } */ ([
@@ -117,6 +119,14 @@ export function stripReleasePrefixes(tag) {
 	);
 }
 
+export function getEventFromGithubEventPath() {
+	let eventPath = ensureEnvVar('GITHUB_EVENT_PATH');
+	if (!path.isAbsolute(eventPath)) {
+		eventPath = import.meta.dirname + '/' + eventPath;
+	}
+	return JSON.parse(fs.readFileSync(eventPath, 'utf8'));
+}
+
 /**
  * @param {any} [pullRequest] Optional pull request object. If not provided, reads from GITHUB_EVENT_PATH
  *
@@ -124,8 +134,7 @@ export function stripReleasePrefixes(tag) {
  */
 export function readPrLabels(pullRequest) {
 	if (!pullRequest) {
-		const eventPath = ensureEnvVar('GITHUB_EVENT_PATH');
-		const event = JSON.parse(fs.readFileSync(eventPath, 'utf8'));
+		const event = getEventFromGithubEventPath();
 		pullRequest = event.pull_request;
 	}
 	/** @type { string[] | { name: string }[] } */
@@ -247,3 +256,38 @@ export function localRefExists(ref) {
 	const res = trySh('git', ['show-ref', '--verify', '--quiet', ref]);
 	return res.ok;
 }
+
+/**
+ * Initializes octokit with GITHUB_TOKEN from env vars.
+ *
+ * Also ensures the existence of useful environment variables.
+ * */
+export function initGithub() {
+	const token = ensureEnvVar('GITHUB_TOKEN');
+	const repoFullName = ensureEnvVar('GITHUB_REPOSITORY');
+
+	const [owner, repo] = repoFullName.split('/');
+
+	const octokit = getOctokit(token);
+
+	return {
+		octokit,
+		owner,
+		repo,
+	};
+}
+
+/**
+ * @param {number} pullRequestId
+ */
+export async function getPullRequestById(pullRequestId) {
+	const { octokit, owner, repo } = initGithub();
+
+	const pullRequest = await octokit.rest.pulls.get({
+		owner,
+		repo,
+		pull_number: pullRequestId,
+	});
+
+	return pullRequest.data;
+}

.github/workflows/backport.yml

@@ -1,6 +1,12 @@
 on:
   pull_request:
     types: [closed]
+  workflow_dispatch:
+    inputs:
+      pull-request-id:
+        description: 'The ID number of the pull request (e.g. 3342). No #, no extra letters.'
+        required: true
+        type: string
 
 permissions:
   contents: write
@@ -8,7 +14,9 @@ permissions:
 
 jobs:
   backport:
-    if: github.event.pull_request.merged == true
+    if: |
+      github.event.pull_request.merged == true ||
+      github.event_name == 'workflow_dispatch'
     runs-on: ubuntu-slim
     steps:
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
@@ -23,6 +31,8 @@ jobs:
 
       - name: Compute backport targets
         id: targets
+        env:
+          PULL_REQUEST_ID: ${{ inputs.pull-request-id }}
         run: node .github/scripts/compute-backport-targets.mjs
 
       - name: Backport
@@ -30,7 +40,7 @@ jobs:
         uses: korthout/backport-action@c656f5d5851037b2b38fb5db2691a03fa229e3b2 # v4.0.1
         with:
           github_token: ${{ secrets.GITHUB_TOKEN }}
-          source_pr_number: ${{ github.event.pull_request.number }}
+          source_pr_number: ${{ github.event.pull_request.number || inputs.pull-request-id }}
           target_branches: ${{ steps.targets.outputs.target_branches }}
           pull_description: |-
             # Description