Pull request comment context

When viewing a commit in a PR, automatically add the current URL to newly opened comments, to show the context in which the reviewer made the comment.

您需要先安装一款用户脚本管理器扩展,例如 Tampermonkey 篡改猴Greasemonkey 油猴子Violentmonkey 暴力猴,才能安装此脚本。

您需要先安装一款用户脚本管理器扩展,例如 Tampermonkey 篡改猴,才能安装此脚本。

您需要先安装一款用户脚本管理器扩展,例如 Tampermonkey 篡改猴Violentmonkey 暴力猴,才能安装此脚本。

您需要先安装一款用户脚本管理器扩展,例如 Tampermonkey 篡改猴Userscripts ,才能安装此脚本。

您需要先安装一款用户脚本管理器扩展,例如 Tampermonkey 篡改猴,才能安装此脚本。

您需要先安装一款用户脚本管理器扩展后才能安装此脚本。

(我已经安装了用户脚本管理器,让我安装!)

您需要先安装一款用户样式管理器扩展,比如 Stylus,才能安装此样式。

您需要先安装一款用户样式管理器扩展,比如 Stylus,才能安装此样式。

您需要先安装一款用户样式管理器扩展,比如 Stylus,才能安装此样式。

您需要先安装一款用户样式管理器扩展后才能安装此样式。

您需要先安装一款用户样式管理器扩展后才能安装此样式。

您需要先安装一款用户样式管理器扩展后才能安装此样式。

(我已经安装了用户样式管理器,让我安装!)

// ==UserScript==
// @name         Pull request comment context
// @namespace    http://stderr.nl
// @version      2026-01-19
// @description  When viewing a commit in a PR, automatically add the current URL to newly opened comments, to show the context in which the reviewer made the comment.
// @author       Matthijs Kooijman <[email protected]>
// @license      CC0-1.0-Universal, https://creativecommons.org/publicdomain/zero/1.0/
// @homepage     https://codeberg.org/matthijs/greasemonkey-pr-comment-context
// @match        https://github.com/*
// @grant        none
// ==/UserScript==

// This script has no URL filter above, since github dynamically loads pages, so we also dynamically match the current URL
const URL_MATCH = /https:\/\/github.com\/[^\/]*\/[^\/]*\/pull\/[^\/]*\/changes\/.*/;

(function() {
    'use strict';

    const PREFIX = "Comment about "

    function process(textarea) {
        // Add a delay, since there seems to be some startup code that runs
        // *after* the textarea was created that clears the textarea (possibly
        // loads a previous value?).
        // 500ms was not enough, 1000ms sometimes, 2000ms seems to always work
        // (and if you already start typing something, the extra content is
        // neatly prepended).
        setTimeout(function() {
            if (textarea.textContent.startsWith(PREFIX)) {
                console.log("Not modifiying textarea, already has prefix", textarea);
            } else {
                //textarea.focus();
                console.log("Adding URL to textarea", textarea);
                // Normally, you would modify the contents, not the value of a
                // textarea, but this stopped working when the GH markdown
                // editor was further javascriptified somewhere end 2025. Now
                // it works to set the value (which is displayed immediately)
                // and then call change to update the JS internal value
                // somewhere (so the value is not erased again once you start
                // typing).
                // This approach was copied from the use-synthentic-change.ts
                // used by the Github React app.
                textarea.value = PREFIX + window.location + "\n\n" + textarea.value;
                textarea.dispatchEvent(new Event('change', { bubbles: false}));
            }
        }, 2000);
    }

    new MutationObserver(function(mutationsList, observer) {
        if (!document.location.toString().match(URL_MATCH)) {
            return;
        }

        for(const mutation of mutationsList) {
            if (mutation.type === 'childList') {
                for(const node of mutation.addedNodes) {
                    if ('querySelector' in node) {
                        const textarea = node.querySelector('div[class*="ConversationCommentBox"] textarea');
                        if (textarea) {
                            process(textarea);
                        }
                    }
                }
            }
        }
    }).observe(document.body, {childList: true, subtree: true});
})();

// vim: set sw=4 sts=4 et: