Easily override quicklisp projects without using git submodules

Upstream URL



Arnold Noronha <arnold@jipr.io>


Mozilla Public License 2.0
Provided Systems



This is a really simply library to override sytems in Quicklisp, or to add libraries that are not available in Quicklisp.

The goal of this project is to make it easy for people to contribute to existing projects. Currently with Quicklisp, if somebody chooses to contribute, they'd have to wait a month before they can get the updated version, or they'd have to use git submodules to manage their patches. Submodules are super hard to maintain, especially across multiple developers or CI machines.

Quick-patch does one thing, and does it really simply: it checks out a repository at a commit that you specify, and adds it to asdf:*central-registry*. That's it. On subsequent runs if you set it up correctly it won't hit the network.


Currently Quick-patch isn't designed to be interactive. In theory it'll work, as long as you're adding new repos, but don't rely on it for removing patches interactively.

Usually your project has a top-level script that sets things up. Or maybe you're just using an init file. In either case, before you start loading other quicklisp projects, you want to do:

;; Sorry, not in quicklisp yet, but this is kind of proving the
;; point of why we need this, yeah?

(ql:quickload :quick-patch)

Currently we don't have any dependencies, so you can override just about any system in quicklisp.

Now you can set up an override. For example, I recently sent a pull request to cl+ssl. At this point, I needed to use my own patched version, so I added this to my loading script:

(quick-patch:register "https://github.com/tdrhq/cl-plus-ssl"

Notice I used the full git commit hash. A partial hash or a tag/branch name will work, but it will cause quick-patch to hit the network and do a fetch on every startup, and it can get really annoying. With the full SHA hash, we can quickly check on subsequent runs that the repo we checked-out is on the correct commit. So this is how I recommend you use it.

Finally, we need to tell quick-patch to do all the work required to fetch stuff.

(quick-patch:checkout-all "build/quick-patch/")

checkout-all takes one argument which is going to be your cache directory. If this is under a git repository, make sure your cache directory is in your .gitignore.

Now I can go ahead and (ql:quickload ...) or (asdf:load-system ...) any other project that depends on cl+ssl, and it'll correctly pick out my patched version.

Happy hacking!


Mozilla Public License, v2.

(No specific reason for the license, it's mostly arbitrarily chosen, but this is what it is at the moment.)

We have copy-pasted some code in quickpatch/util from other libraries to keep our dependencies minimal, and this code might be under a difference license:

directory-exists-p and catdir are taken from cl-fad which is Copyright Edmund Weitz and released under BSD 2 Clause.

trim is taken from cl-str which is Copyright @vindarel, and under the MIT License.


Arnold Noronha arnold@tdrhq.com. While you're here, may I recommend Screenshotbot?

wait wait, a real world example

Speaking of Screenshotbot, you can see how we use it quick-patch in the real-world: https://github.com/screenshotbot/screenshotbot-oss/blob/main/scripts/init.lisp

Roughly speaking, we build an image that we always work with, and the image has a hook that runs every time the image starts, and that hooks sets up quick-patch.

Dependencies (4)

  • cl-mock
  • cl-str
  • fiveam
  • tmpdir

Dependents (0)

    • GitHub
    • Quicklisp