ZX script to prefix the PR title with the linear ticket from the branch name or PR description. Can only run in GitHub CI.

script.mjs

#!/usr/bin/env zx

let token = process.env.GITHUB_TOKEN;
let branchName = process.env.GITHUB_HEAD_REF;
let pullNumber = process.env.PULL_NUMBER;
let apiUrl = process.env.GITHUB_API_URL;
let repo = process.env.GITHUB_REPOSITORY;
let issuePrefix = process.env.ISSUE_PREFIX
let allowFailure = process.env.ALLOW_FAILURE

console.log("Branch name:", branchName);
console.log("Pull number:", pullNumber);
console.log("Github api url:", apiUrl);
console.log("Repo:", repo);

let pr = `${apiUrl}/repos/${repo}/pulls/${pullNumber}`;
let requestHeaders = {
  Accept: "application/vnd.github.v3+json",
  Authorization: `token ${token}`,
}

let resp = await fetch(pr, {
  method: "GET",
  headers: requestHeaders,
});
if (!resp.ok) {
  console.error("Could not get PR: %s", resp.statusText);
  process.exit(1)
}
let data = await resp.json();
let prTitle = data.title
let prBody = data.body

console.log("Current PR title: %s", prTitle);

const regex = new RegExp(`(${issuePrefix}[0-9]+)`, "igm")
const matchFromTitle = prTitle.match(regex);
const matchFromBranch = branchName.match(regex);
const matchFromBody = prBody.match(regex);
let ticket = ''

if (matchFromTitle !== null && matchFromTitle.length > 0) {
  console.log("PR title already contains issue");
  process.exit(0)
}

if (matchFromBody !== null && matchFromBody.length > 0) {
  ticket = matchFromBody[0]
} else if (matchFromBranch !== null && matchFromBranch.length > 0) {
  ticket = matchFromBranch[0]
}

if (!ticket) {
  console.error("Could not extract issue from branch name");
  process.exit(allowFailure ? 0 : 1)
}

const newPRTitle = ticket.toUpperCase() + ": " + prTitle.trim()
console.error("PR title updated: %s", newPRTitle);

resp = await fetch(pr, {
  method: "PATCH",
  body: JSON.stringify({ title: newPRTitle }),
  headers: requestHeaders,
});
if (!resp.ok) {
  console.error("Could not update PR title to: %s, error: %s", resp.statusText, newPRTitle);
  process.exit(allowFailure ? 0 : 1)
}