Add output and improve logging (#88)

.github/workflows/backport.yml

@@ -7,8 +7,8 @@ on:
 
 jobs:
   backport:
-    runs-on: ubuntu-18.04
     name: Backport
+    runs-on: ubuntu-latest
     # Only react to merged PRs for security reasons.
     # See https://docs.github.com/en/actions/using-workflows/events-that-trigger-workflows#pull_request_target.
     if: >
@@ -21,7 +21,6 @@ jobs:
         )
       )
     steps:
-      - name: Backport
-        uses: tibdex/backport@v2
+      - uses: tibdex/backport@v2
         with:
           github_token: ${{ secrets.GITHUB_TOKEN }}

.github/workflows/publish.yml

@@ -7,7 +7,7 @@ on:
 jobs:
   publish:
     name: Publish
-    runs-on: ubuntu-18.04
+    runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v1
       - uses: dylanvann/publish-github-action@v1.1.49

action.yml

@@ -1,6 +1,7 @@
 name: Backporting
 author: Thibault Derousseaux <tibdex@gmail.com>
-description: Automatically backport PRs to other branches by simply labeling them.
+description: >
+  Automatically backport PRs to other branches by simply labeling them.
 inputs:
   body_template:
     description: >
@@ -11,7 +12,10 @@ inputs:
         - body: original PR's body
         - mergeCommitSha: SHA of the original PR's merge commit
         - number: original PR's number
-    default: "Backport <%= mergeCommitSha %> from #<%= number %>"
+    default: "Backport <%= mergeCommitSha %> from #<%= number %>."
+  github_token:
+    description: Token for the GitHub API.
+    required: true
   head_template:
     description: >
       Lodash template for the backport PR's head branch.
@@ -33,9 +37,6 @@ inputs:
         - base: backport PR's base branch
         - labels: array containing the original PR's labels, excluding those matching `label_pattern`.
     default: "[]"
-  github_token:
-    description: Token for the GitHub API.
-    required: true
   title_template:
     description: >
       Lodash template for the backport PR's title.
@@ -45,6 +46,9 @@ inputs:
         - number: original PR's number
         - title: original PR's title
     default: "[Backport <%= base %>] <%= title %>"
+outputs:
+  created_pull_requests:
+    description: A JSON stringified object mapping the base branch of the created pull requests to their number.
 runs:
   using: node16
   main: dist/index.js

package.json

@@ -1,6 +1,6 @@
 {
   "name": "backport",
-  "version": "2.0.1",
+  "version": "2.0.2",
   "license": "MIT",
   "main": "dist/index.js",
   "files": [

src/backport.ts

@@ -91,11 +91,11 @@ const backportOnce = async ({
   commitSha: string;
   github: InstanceType<typeof GitHub>;
   head: string;
-  labels: string[];
+  labels: readonly string[];
   owner: string;
   repo: string;
   title: string;
-}>) => {
+}>): Promise<number> => {
   const git = async (...args: string[]) => {
     await exec("git", args, { cwd: repo });
   };
@@ -125,12 +125,15 @@ const backportOnce = async ({
       "PUT /repos/{owner}/{repo}/issues/{issue_number}/labels",
       {
         issue_number: number,
-        labels,
+        labels: [...labels],
         owner,
         repo,
       },
     );
   }
+
+  info(`PR #${number} has been created.`);
+  return number;
 };
 
 const getFailedBackportCommentBody = ({
@@ -212,7 +215,7 @@ const backport = async ({
   labelRegExp: RegExp;
   payload: PullRequestClosedEvent | PullRequestLabeledEvent;
   token: string;
-}) => {
+}): Promise<{ [base: string]: number }> => {
   const {
     pull_request: {
       body: originalBody,
@@ -238,14 +241,15 @@ const backport = async ({
   const baseBranches = getBaseBranches({ labelRegExp, payload });
 
   if (baseBranches.length === 0) {
-    return;
+    info("No backports required.");
+    return {};
   }
 
   const github = getOctokit(token);
 
   await warnIfSquashIsNotTheOnlyAllowedMergeMethod({ github, owner, repo });
 
-  info(`Backporting ${mergeCommitSha} from #${number}`);
+  info(`Backporting ${mergeCommitSha} from #${number}.`);
 
   await exec("git", [
     "clone",
@@ -259,6 +263,8 @@ const backport = async ({
   ]);
   await exec("git", ["config", "--global", "user.name", "github-actions[bot]"]);
 
+  const createdPullRequestBaseBranchToNumber: { [base: string]: number } = {};
+
   for (const base of baseBranches) {
     const body = getBody({
       base,
@@ -277,9 +283,9 @@ const backport = async ({
 
     // PRs are handled sequentially to avoid breaking GitHub's log grouping feature.
     // eslint-disable-next-line no-await-in-loop
-    await group(`Backporting to ${base} on ${head}`, async () => {
+    await group(`Backporting to ${base} on ${head}.`, async () => {
       try {
-        await backportOnce({
+        const backportPullRequestNumber = await backportOnce({
           base,
           body,
           commitSha: mergeCommitSha,
@@ -290,6 +296,7 @@ const backport = async ({
           repo,
           title,
         });
+        createdPullRequestBaseBranchToNumber[base] = backportPullRequestNumber;
       } catch (_error: unknown) {
         const error = ensureError(_error);
         logError(error);
@@ -311,6 +318,8 @@ const backport = async ({
       }
     });
   }
+
+  return createdPullRequestBaseBranchToNumber;
 };
 
 export { backport };

src/index.ts

@@ -1,4 +1,4 @@
-import { getInput, setFailed } from "@actions/core";
+import { getInput, setFailed, setOutput } from "@actions/core";
 import { context } from "@actions/github";
 import type { PullRequestEvent } from "@octokit/webhooks-types";
 import ensureError from "ensure-error";
@@ -14,9 +14,6 @@ const run = async () => {
       "title_template",
     ].map((name) => template(getInput(name)));
 
-    const labelPattern = getInput("label_pattern");
-    const token = getInput("github_token", { required: true });
-
     const getLabels = ({
       base,
       labels,
@@ -32,8 +29,15 @@ const run = async () => {
       }
     };
 
+    const labelPattern = getInput("label_pattern");
     const labelRegExp = new RegExp(labelPattern);
 
+    const token = getInput("github_token", { required: true });
+
+    if (!context.payload.pull_request) {
+      throw new Error(`Unsupported event action: ${context.payload.action}.`);
+    }
+
     const payload = context.payload as PullRequestEvent;
 
     if (payload.action !== "closed" && payload.action !== "labeled") {
@@ -42,7 +46,7 @@ const run = async () => {
       );
     }
 
-    await backport({
+    const createdPullRequestBaseBranchToNumber = await backport({
       getBody,
       getHead,
       getLabels,
@@ -51,6 +55,10 @@ const run = async () => {
       payload,
       token,
     });
+    setOutput(
+      "created_pull_requests",
+      JSON.stringify(createdPullRequestBaseBranchToNumber),
+    );
   } catch (_error: unknown) {
     const error = ensureError(_error);
     setFailed(error);

xo.config.cjs

@@ -4,8 +4,15 @@ module.exports = {
   extends: ["prettier"],
   overrides: [
     {
-      files: "**/*.{ts,tsx}",
+      files: "**/*.ts",
       rules: {
+        // Index signatures are slightly more legible since the key must be named.
+        "@typescript-eslint/consistent-indexed-object-style": [
+          "error",
+          "index-signature",
+        ],
+        // Too restrictive.
+        "@typescript-eslint/restrict-template-expressions": "off",
         // Covered by TypeScript.
         "default-case": "off",
       },