---
title: "Contributing"
description: ""
summary: ""
date: 2025-03-14T14:14:35+01:00
lastmod: 2025-03-14T14:14:35+01:00
draft: false
weight: 12
toc: true
---

You want to start contributing? Nice!

We do use [Gerrit](https://www.gerritcodereview.com) for Code Review.
It allows a more granular review (per-commit granularity rather than PR
granularity), as well as keeping track as how commits change over time.
It greatly simplifies the review process, and leads to overall more high-quality
contributions.

While it might initially look a bit intimidating, you hopefully will spend less
time learning its workflow than writing actual Snix code.
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{{<callout>}}
This assumes you have the repo already cloned and the necessary tools installed
as described in [Building Snix]({{< relref "./building" >}}), so make sure you
went through these instructions first.
{{</callout>}}

### Creating a Gerrit account
 - Navigate to [our Gerrit instance][snix-gerrit]. Hit the "Sign in" button
   (which allows SSO with some common IdPs)
 - In the User settings, paste an SSH public key and hit the "Add New SSH key"
   button. [^1]
 - Alternatively, you can also create "HTTP Credentials" (though saving the HTTP
   password is messy).

### Update your git remote URL
Instead of trying to push to Forgejo, reconfigure your git remote URL to
interact with Gerrit directly.

Replace `$USER` with your `Username` shown in the Gerrit settings.

#### If using SSH authentication:
```console
$ git remote set-url origin "ssh://$USER@cl.snix.dev:29418/snix"
```


#### If using HTTP authentication:
```console
$ git remote set-url origin "https://$USER@cl.snix.dev/a/snix"
```

<!-- TODO: fix replication to include refs/changes/… etc, and ensure it
replicates fast enough, then update to --push only -->

### Install the commit-msg hook
Gerrit uses a `commit-msg` hook to add a `Change-Id: …` field to each commit
message if not present already. This allows Gerrit to identify new revisions /
updates of old commits, and track them as new revisions of the same "CL" [^2].

To install the commit-msg hook, run the following from the repo root:

```console
$ mkdir -p .git/hooks
$ curl -Lo .git/hooks/commit-msg https://cl.snix.dev/tools/hooks/commit-msg
$ chmod +x .git/hooks/commit-msg
```

{{< callout context="tip" title="Did you know?" icon="outline/rocket" >}}
Gerrit refuses receiving commits without these `Change-Id: …` fields.

If you already have some local commits without `Change-Id` field, `git commit
--amend` them after installing the `commit-msg` hook to add them.
{{< /callout >}}

### Push your changes
Do some local changes, and push them to Gerrit as follows:

```console
$ git push origin HEAD:refs/for/canon
```

Gerrit will print links to newly created CLs to your terminal.

If you want to update/edit your CL, simply squash these changes into your local
commit and push again.

### The Gerrit model
If do not have experience with the Gerrit, consider reading the
[<cite>Working with Gerrit: An example</cite>][Gerrit Walkthrough] or
[<cite>Basic Gerrit Walkthrough — For GitHub Users</cite>][gerrit-for-github-users].

Some more tips:

 * Assign a reviewer to review your changes.
 * React on comments and mark them as resolved once you did.
   * Comments are only "Drafts" (stored server-side) until you send them off.
     This can be done by the `Reply` button on the top, for example.
 * Once CI is green, it's up to the *Author* of the CL to submit, not the
   reviewer.
   If you want a bot to automatically submit in this case, you can add the
   `Autosubmit+1` label.
 * Rebase on `origin/canon` regularly. You cannot push if you still have an old
   version of a now-submitted CL in your git log.

{{< callout context="tip" title="Did you know?" icon="outline/rocket" >}}
You can immediately assign reviewers and other fields while pushing a
new/updated change, by adding it to the push URL.

```console
$ git push origin HEAD:refs/for/canon%r=alice,cc=bob,l=Autosubmit+1,publish-comments
```
 * will set `alice` as a reviewer
 * will set `bob` as CC
 * adds the `Autosubmit+1` label
 * publishes any outstanding draft comments
{{< /callout >}}


[snix-gerrit]: https://cl.snix.dev
[Gerrit walkthrough]: https://gerrit-review.googlesource.com/Documentation/intro-gerrit-walkthrough.html
[gerrit-for-github-users]: https://gerrit.wikimedia.org/r/Documentation/intro-gerrit-walkthrough-github.html
[^1]: currently, `ssh-*-sk` keytypes are not supported, so use an `ssh-ed25519` key.
[^2]: abbreviation for "change list", and the review unit in Gerrit.
