meta: request reviews from github actions

.github/workflows/request-reviews.yml

@@ -0,0 +1,24 @@
+name: Request reviews for PRs
+
+on:
+  pull_request_target:
+    types: [opened]
+
+permissions:
+  contents: read
+  pull-requests: write
+  issues: write
+
+jobs:
+  main:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@a5ac7e51b41094c92402da3b24376905380afc29  # v4.1.6
+        name: Checkout default branch
+      - uses: actions/github-script@60a0d83039c74a4aee543508d2ffcb1c3799cdea  # v7.0.1
+        name: Make initial comment
+        with:
+          script: |
+            const initialCommentBuilder = require('${{ github.workspace }}/tools/actions/pr-open.js');
+            await initialCommentBuilder(github, context);

tools/actions/pr-open.js

@@ -0,0 +1,86 @@
+'use strict';
+
+module.exports = async (client, context) => {
+  function globToRegex(glob) {
+    const patterns = {
+      '*': '([^\\/]+)',
+      '**': '(.+\\/)?([^\\/]+)',
+      '**/': '(.+\\/)',
+    };
+
+    const escapedGlob = glob.replace(/\./g, '\\.').replace(/\*\*$/g, '(.+)');
+    const regexString = '^(' + escapedGlob.replace(/\*\*\/|\*\*|\*/g, (match) => patterns[match] || '') + ')$';
+    return new RegExp(regexString);
+  }
+
+  class CodeOwners {
+    constructor(fileContent) {
+      this.owners = fileContent.split('\n').map((line) => line.trim())
+                .filter((line) => line && !line.startsWith('#'))
+                .map((line) => {
+                  const [path, ...owners] = line.split(/\s+/);
+                  return { path: globToRegex(path), owners };
+                });
+    }
+
+    getOwners(filePath) {
+      const normalizedPath = filePath.startsWith('/') ? filePath : `/${filePath}`;
+      return this.owners
+                .filter(({ path }) => path.test(normalizedPath))
+                .flatMap(({ owners }) => owners);
+    }
+  }
+
+  async function getChangedFiles(base, head) {
+    const { data } = await client.rest.repos.compareCommits({
+      owner: context.repo.owner,
+      repo: context.repo.repo,
+      base,
+      head,
+    });
+    return data.files.map((file) => file.filename);
+  }
+
+  async function getCodeOwners() {
+    const { data } = await client.rest.repos.getContent({
+      owner: context.repo.owner,
+      repo: context.repo.repo,
+      path: '.github/CODEOWNERS',
+    });
+
+    const content = Buffer.from(data.content, 'base64').toString('utf8');
+    return new CodeOwners(content);
+  }
+
+  async function makeInitialComment(changedFiles) {
+    const codeOwners = await getCodeOwners();
+
+    const owners = new Set();
+    changedFiles.forEach((file) => {
+      codeOwners.getOwners(file).forEach((owner) => owners.add(owner));
+    });
+
+    const ownersList = Array.from(owners).map((owner) => `- ${owner}`).join('\n');
+
+    const body =
+            'The following teams have been pinged to review your changes:\n\n' +
+            ownersList;
+
+    return client.rest.issues.createComment({
+      owner: context.repo.owner,
+      repo: context.repo.repo,
+      issue_number: context.payload.pull_request.number,
+      body: body,
+    });
+  }
+
+  const base = context.payload.pull_request?.base?.sha;
+  const head = context.payload.pull_request?.head?.sha;
+
+  if (!base || !head) {
+    throw new Error('Cannot get base or head commit');
+  }
+
+  const changedFiles = await getChangedFiles(base, head);
+  await makeInitialComment(changedFiles);
+};