Open Linear reviews in GitHub

open-linear-reviews-in-github.user.js

// ==UserScript==
// @name         Open Linear reviews in GitHub
// @namespace    http://tampermonkey.net/
// @version      2026-09-11
// @description  Open Linear reviews in GitHub
// @author       Warren Seine
// @match        https://linear.app/*
// @icon         https://www.google.com/s2/favicons?sz=64&domain=linear.app
// @run-at       document-idle
// @grant        none
// ==/UserScript==

(function() {
  'use strict';

  // Review pages live at /<workspace>/review/<slug>, with tabs below them.
  const REVIEW = /^\/([^/]+)\/review\/([^/]+)/;

  // The subheader's actions button names the pull request in full. It is there
  // on every tab of the review, including the Diff, where nothing links out.
  const ACTIONS = 'button[aria-label*="pull request actions"]';
  const OWNER_REPO_NUMBER = /^([A-Za-z0-9._-]+)\/([A-Za-z0-9._-]+)#(\d+)/;

  // Older review pages link out instead, e.g. https://github.com/owner/repo/pull/7958.
  const PULL_REQUEST = /^https:\/\/github\.com\/[^/]+\/[^/]+\/pull\/\d+$/;

  // Such a link renders as repo#number. Links inside the description point at
  // other pull requests, so the text shape tells them apart.
  const SHORTHAND = /^[A-Za-z0-9._-]+#\d+$/;

  // Append ?stay to a review URL to read it in Linear instead.
  const STAY = 'stay';

  // A fragment points at something inside the review — a comment, a thread. No
  // shared identifier exists for those on the GitHub side, so a redirect would
  // drop the reader at the top of the pull request rather than at what they
  // clicked. Those links stay in Linear.
  const ANCHORED = () => document.location.hash.length > 1;

  // Linear drops the fragment once the comment is dealt with — resolved, or
  // navigated away from — and the reader would then be redirected out of the
  // page they deliberately opened. So the decision to stay is remembered for
  // the review, for as long as the tab lives.
  const REMEMBERED = 'linear-review-stay:';

  // The page is a client-side app, so the link appears some time after the URL
  // does. Give up rather than redirect a review that has been open for a while.
  const TIMEOUT = 20000;

  let review = null;
  let since = 0;

  function reviewKey() {
    const parts = REVIEW.exec(document.location.pathname);
    // The tab below the review (/changes and friends) is not part of identity:
    // switching tabs must not forget the decision.
    return parts ? `${REMEMBERED}${parts[1]}/${parts[2]}` : null;
  }

  function remember(key) {
    // Storage is unavailable in some browser configurations; the fragment check
    // still holds on its own there.
    try {
      sessionStorage.setItem(key, '1');
    } catch (error) {
      /* ignore */
    }
  }

  function remembered(key) {
    try {
      return sessionStorage.getItem(key) !== null;
    } catch (error) {
      return false;
    }
  }

  function pullRequestUrl() {
    for (const button of document.querySelectorAll(ACTIONS)) {
      const parts = OWNER_REPO_NUMBER.exec(button.getAttribute('aria-label'));
      if (parts) return `https://github.com/${parts[1]}/${parts[2]}/pull/${parts[3]}`;
    }

    const candidates = [...document.querySelectorAll('a[href*="/pull/"]')]
      .filter(a => PULL_REQUEST.test(a.href) && SHORTHAND.test(a.textContent.trim()));
    if (!candidates.length) return null;

    // Several links carry the shorthand; the topmost is the subheader, which
    // always belongs to this review.
    candidates.sort((a, b) => a.getBoundingClientRect().top - b.getBoundingClientRect().top);
    return candidates[0].href;
  }

  function redirect() {
    const key = reviewKey();
    if (!key) {
      review = null;
      return;
    }

    if (new URLSearchParams(document.location.search).has(STAY) || ANCHORED()) {
      remember(key);
      return;
    }

    if (remembered(key)) return;

    if (review !== document.location.pathname) {
      review = document.location.pathname;
      since = Date.now();
    }

    if (Date.now() - since > TIMEOUT) return;

    const url = pullRequestUrl();
    // Replace rather than assign: the review drops out of the history, so going
    // back lands on whatever came before it instead of redirecting again.
    if (url) document.location.replace(url);
  }

  // Reviews are opened by client-side navigation as often as by page load, and
  // the link renders late, so poll instead of running once.
  setInterval(redirect, 300);
  redirect();
})();