Allow GitHub forks to be configured to default to self for pull request base
// ==UserScript==
// @name GitHub Fork Default
// @namespace https://github.com/logiclrd/GitHubForkDefault/
// @version 2025-08-01
// @description Allow GitHub forks to be configured to default to self for pull request base
// @author You
// @match *://*/*
// @icon https://github.com/logiclrd/GitHubForkDefault/blob/main/PRIcon.png?raw=true
// @license MIT
// @require https://openuserjs.org/src/libs/sizzle/GM_config.js
// @grant GM_getValue
// @grant GM_setValue
// @grant GM_getTab
// @grant GM_saveTab
// @grant GM.getValue
// @grant GM.setValue
// @grant GM.getTab
// @grant GM.saveTab
// ==/UserScript==
(function() {
'use strict';
var config =
{
DefaultToSelfRepos: [""]
};
async function updateConfig(defaultToSelfReposStr)
{
try
{
config.DefaultToSelfRepos = defaultToSelfReposStr.split(/ ,\n/g).filter(i => i);
await GM.setValue("DefaultToSelfRepos", JSON.stringify(config.DefaultToSelfRepos));
}
catch { }
}
try
{
config.DefaultToSelfRepos = JSON.parse(GM_getValue("DefaultToSelfRepos", "[]"));
}
catch { }
var gmc =
new GM_config(
{
"id": "GitHubPRDefaults",
"title": "GitHub PR Defaults",
"css":
{
"basic": "width: 75%; height: 25%;"
},
"fields":
{
"DefaultToSelfRepos":
{
"section": "List of repositories that should default to self for pull requests",
"label": "Default-to-Self Repos (one per line and/or comma-separated)",
"type": "textarea",
"rows": 15,
"cols": 60,
"default": "myusername/myreponame..."
}
},
"events":
{
"init": function() { this.set("DefaultToSelfRepos", config.DefaultToSelfRepos.join('\n')); },
"save":
function()
{
updateConfig(this.get("DefaultToSelfRepos"));
window.location.reload();
}
}
});
var tabData = {};
function pullComponent(path, separator)
{
var index = path.indexOf(separator);
if (index >= 0)
return [path.substring(0, index), path.substring(index + separator.length).trimStart(separator)];
else
return [path, ''];
}
function isValidOwnerName(name) { return /^[a-z\d](?:[a-z\d]|-(?=[a-z\d])){0,38}$/i.test(name); }
function isValidRepoName(name) { return /[a-z\d.-_]+/i.test(name); }
function isValidBranchName(name)
{
return (
new RegExp("^(?!/|.*(?:[/.]\\.|//|@\\{|\\\\))[^\\040\\177 ~^:?*[]+(?<!\\.lock)(?<![/.])$").test(name) &&
!/[0-9a-f]{40}/i.test(name) && // GitHub-specific
!name.startsWith("refs/")); // GitHub-specific
}
function decodePullRequestURL(url)
{
if (url.host != "github.com")
return null;
var path = url.pathname.replace(/^\/+/g, '');
var baseOwner, baseRepo, operation, baseBranch, headOwner, headRepo, headBranch;
[baseOwner, path] = pullComponent(path, '/');
[baseRepo, path] = pullComponent(path, '/');
[operation, path] = pullComponent(path, '/');
[baseBranch, path] = pullComponent(path, '...');
[headOwner, path] = pullComponent(path, ':');
if (path.indexOf(':') < 0)
[headRepo, headBranch, path] = [baseRepo, path, ''];
else
{
[headRepo, path] = pullComponent(path, ':');
[headBranch, path] = [path, ''];
}
if (operation !== "compare")
return null;
if (!isValidOwnerName(baseOwner) || !isValidRepoName(baseRepo) || !isValidBranchName(baseBranch))
return null;
if (!isValidOwnerName(headOwner) || !isValidRepoName(headRepo) || !isValidBranchName(headBranch))
return null;
var decoded =
{
Base:
{
Owner: baseOwner,
Repo: baseRepo,
Branch: baseBranch
},
Head:
{
Owner: headOwner,
Repo: headRepo,
Branch: headBranch
},
Params: url.search
};
return decoded;
}
function encodePullRequestURL(pr)
{
return `https://github.com/${pr.Base.Owner}/${pr.Base.Repo}/compare/${pr.Base.Branch}...${pr.Head.Owner}:${pr.Head.Repo}:${pr.Head.Branch}${pr.Params}`;
}
function isPullRequestURL(url)
{
return decodePullRequestURL(url) != null;
}
function isBadPullRequestURL(url)
{
var pr = decodePullRequestURL(url);
if (pr == null)
return false;
var baseRepoQualifiedName = pr.Base.Owner + '/' + pr.Base.Repo;
var headRepoQualifiedName = pr.Head.Owner + '/' + pr.Head.Repo;
if (!config.DefaultToSelfRepos.includes(headRepoQualifiedName))
return false;
return baseRepoQualifiedName !== headRepoQualifiedName;
}
function isGoodPullRequestURL(url)
{
var pr = decodePullRequestURL(url);
if (pr == null)
return false;
var baseRepoQualifiedName = pr.Base.Owner + '/' + pr.Base.Repo;
var headRepoQualifiedName = pr.Head.Owner + '/' + pr.Head.Repo;
if (!config.DefaultToSelfRepos.includes(headRepoQualifiedName))
return false;
return baseRepoQualifiedName === headRepoQualifiedName;
}
function convertBadToGood(url)
{
var pr = decodePullRequestURL(url);
if (pr == null)
return url;
pr.Base.Owner = pr.Head.Owner;
pr.Base.Repo = pr.Head.Repo;
return encodePullRequestURL(pr);
}
async function check()
{
// https://github.com/schismtracker/schismtracker/compare/master...logiclrd:schismtracker:test-pr-thinger?expand=1
var urlRaw = window.location.href;
var url = URL.parse(urlRaw);
var tabData = await GM.getTab();
if (!("LastURL" in tabData))
tabData.LastURL = "about:";
var lastURL = URL.parse(tabData.LastURL);
tabData.LastURL = urlRaw;
await GM.saveTab(tabData);
if (isPullRequestURL(url))
{
var configButton = document.createElement("button");
configButton.className = "btn Button--small";
configButton.innerText = "Configure Base Defaults";
configButton.onclick = () => gmc.open();
var panelCandidates = document.getElementsByClassName("range-editor");
if (panelCandidates.length < 1)
alert("Couldn't insert configuration button: can't find range editor");
else
{
var panel = panelCandidates[0];
panel.appendChild(configButton);
}
}
if (isBadPullRequestURL(url) && !isGoodPullRequestURL(lastURL))
window.location.href = convertBadToGood(url);
}
window.addEventListener("load", check);
var originalPushState = window.history.pushState;
window.history.pushState =
function ()
{
originalPushState.apply(window.history, arguments);
setTimeout(check, 10);
};
})();