How to determine which forks on GitHub are ahead?

Question

Sometimes, the original GitHub repository of a piece of software I'm using, such as linkchecker, is seeing little or no development, while a lot of forks have been created (in this case: 142, at the time of writing).

For each fork, I'd like to know:

• which branches it has with commits ahead of the original master branch

and for each such branch:

• how many commits it is ahead of the original
• how many commits it is behind

GitHub has a web interface for comparing forks, but I don't want to do this manually for each fork, I just want a CSV file with the results for all forks. How can this be scripted? The GitHub API can list the forks, but I can't see how to compare forks with it. Cloning every fork in turn and doing the comparison locally seems a bit crude.

Answer 1

After clicking "Insights" on top and then "Forks" on the left, the following bookmarklet prints the info directly onto the web page like this:

The code to add as a bookmarklet (or to paste into the console):

javascript:(async () => {
  /* while on the forks page, collect all the hrefs and pop off the first one (original repo) */
  const aTags = [...document.querySelectorAll('div.repo a:last-of-type')].slice(1);

  for (const aTag of aTags) {
    /* fetch the forked repo as html, search for the "This branch is [n commits ahead,] [m commits behind]", print it directly onto the web page */
    await fetch(aTag.href)
      .then(x => x.text())
      .then(html => aTag.outerHTML += `${html.match(/This branch is.*/).pop().replace('This branch is', '').replace(/([0-9]+ commits? ahead)/, '<font color="#0c0">$1</font>').replace(/([0-9]+ commits? behind)/, '<font color="red">$1</font>')}`)
      .catch(console.error);
  }
})();

You can also paste the code into the address bar, but note that some browsers delete the leading javascript: while pasting, so you'll have to type javascript: yourself. Or copy everything except the leading j, type j, and paste the rest.

It has been modified from this answer.

---

Bonus

The following bookmarklet also prints the links to the ZIP files:

The code to add as a bookmarklet (or to paste into the console):

javascript:(async () => {
  /* while on the forks page, collect all the hrefs and pop off the first one (original repo) */
  const aTags = [...document.querySelectorAll('div.repo a:last-of-type')].slice(1);

  for (const aTag of aTags) {
    /* fetch the forked repo as html, search for the "This branch is [n commits ahead,] [m commits behind]", print it directly onto the web page */
    await fetch(aTag.href)
      .then(x => x.text())
      .then(html => aTag.outerHTML += `${html.match(/This branch is.*/).pop().replace('This branch is', '').replace(/([0-9]+ commits? ahead)/, '<font color="#0c0">$1</font>').replace(/([0-9]+ commits? behind)/, '<font color="red">$1</font>')}` + " <a " + `${html.match(/href="[^"]*\.zip">/).pop() + "Download ZIP</a>"}`)
      .catch(console.error);
  }
})();

Answer 2

Had exactly the same itch and wrote a scraper that takes the info printed in the rendered HTML for forks: https://github.com/hbbio/forkizard

Definitely not perfect, but a temporary solution.

Answer 3

useful-forks

useful-forks is an online tool which filters all the forks based on ahead criteria. I think it answers your needs quite well. :)

For the repo in your question, you could do: https://useful-forks.github.io/?repo=wummel/linkchecker

That should provide you with similar results to (ran on 2022-04-02):

Also available as a Chrome plugin

You can check out the GitHub repo if you want to use it as a Chrome plugin, too: https://github.com/useful-forks/useful-forks.github.io#chrome-extension-wip

Disclaimer

I am the maintainer of this project.

Answer 4

Late to the party - I think this is the second time I've ended up on this SO post so I'll share my js-based solution (I ended up making a bookmarklet by just fetching and searching the html pages). You can either create a bookmarklet from this, or simply paste the whole thing into the console. Works on chromium-based and firefox:

EDIT: if there are more than 10 or so forks on the page, you may get locked out for scraping too fast (429 too many requests in network). Use async / await instead:

javascript:(async () => {
  /* while on the forks page, collect all the hrefs and pop off the first one (original repo) */
  const forks = [...document.querySelectorAll('div.repo a:last-of-type')].map(x => x.href).slice(1);

  for (const fork of forks) {
    /* fetch the forked repo as html, search for the "This branch is [n commits ahead,] [m commits behind]", print it to console */
    await fetch(fork)
      .then(x => x.text())
      .then(html => console.log(`${fork}: ${html.match(/This branch is.*/).pop().replace('This branch is ', '')}`))
      .catch(console.error);
  }
})();

or you can do batches, but it's pretty easy to get locked out

javascript:(async () => {
  /* while on the forks page, collect all the hrefs and pop off the first one (original repo) */
  const forks = [...document.querySelectorAll('div.repo a:last-of-type')].map(x => x.href).slice(1);

  getfork = (fork) => {
    return fetch(fork)
      .then(x => x.text())
      .then(html => console.log(`${fork}: ${html.match(/This branch is.*/).pop().replace('This branch is ', '')}`))
      .catch(console.error);
  }

  while (forks.length) {
    await Promise.all(forks.splice(0, 2).map(getfork));
  }
})();

Original (this fires all requests at once and will possibly lock you out if it is more requests/s than github allows)

javascript:(() => {
  /* while on the forks page, collect all the hrefs and pop off the first one (original repo) */
  const forks = [...document.querySelectorAll('div.repo a:last-of-type')].map(x => x.href).slice(1);

  for (const fork of forks) {
    /* fetch the forked repo as html, search for the "This branch is [n commits ahead,] [m commits behind]", print it to console */
    fetch(fork)
      .then(x => x.text())
      .then(html => console.log(`${fork}: ${html.match(/This branch is.*/).pop().replace('This branch is ', '')}`))
      .catch(console.error);
  }
})();

Will print something like:

https://github.com/user1/repo: 289 commits behind original:master.
https://github.com/user2/repo: 489 commits behind original:master.
https://github.com/user2/repo: 1 commit ahead, 501 commits behind original:master.
...

to console.

EDIT: replaced comments with block comments for paste-ability