CONTRIBUTING.md

Contributing to matrix-rust-sdk

Chat rooms

In addition to our main Matrix room, we have a development room at #matrix-rust-sdk-dev:flipdot.org. Please use it to discuss potential changes, the overall direction of development and related topics.

Testing

You can run most of the tests that also happen in CI also using cargo xtask ci. This needs a few dependencies to be installed, as it also runs automatic WASM tests:

rustup component add clippy
cargo install cargo-nextest typos-cli wasm-pack

If you want to execute only one part of CI, there are a few sub-commands (see cargo xtask ci --help).

Some tests are not automatically run in cargo xtask ci, for example the integration tests that need a running synapse instance. These tests reside in ./testing/matrix-sdk-integration-testing. See its README to easily set up a synapse for testing purposes.

Commit messages and PR title guidelines

Ideally, a PR should have a proper title, with atomic logical commits, and each commit should have a good commit message.

An atomic logical commit is one that is ideally small, can be compiled in isolation, and passes tests. This is useful to make the review process easier (help your reviewer), but also when running bisections, helping identifying which commit introduced a regression.

A good commit message should be composed of:

• a prefix to indicate which area/feature is related by the commit
• a short description that would give sufficient context for a reviewer to guess what the commit is about.

Examples of commit messages that aren't so useful:

• “add new method“
• “enhance performance“
• “fix receipts“

Examples of good commit messages:

• “ffi: Add new method frobnicate_the_foos”
• “indexeddb: Break up the request inside get_inbound_group_sessions”
• “read_receipts: Store receipts locally, fixing #12345”

A proper PR title would be a one-liner summary of the changes in the PR, following the same guidelines of a good commit message, including the area/feature prefix. Something like FFI: Allow logs files to be pruned. would be a good PR title.

(An additional bad example of a bad PR title would be mynickname/branch name, that is, just the branch name.)

Having good commit messages and PR titles also helps with reviews, scanning the git log of the project, and writing the This week in Matrix updates for the SDK.

Review process

To streamline the review process and make it easier for maintainers to review your contributions, follow these basic rules:

1. Do not force push after a review has started. This helps maintainers track incremental changes without confusion and makes it easier to follow the evolution of the code.

2. Do not mix moves and refactoring with functional changes. Keep these in separate commits for clarity. This ensures that the purpose of each commit is clear and easy to review.

3. Each commit must compile. If commits don’t compile, git bisect becomes unusable, which hampers the debugging process and makes it harder to identify the source of issues.

4. Commits should only introduce test failures if they are proving that a bug exists. New features should never introduce test failures. Test failures should only be used to demonstrate existing bugs, not as part of adding new functionality.

5. Keep PRs on topic and small. Large PRs are harder to review and more prone to delays. Create small, focused commits that address a single topic. Use a combination of git add -p or git checkout -p to split changes into logical units. This makes your work easier to review and reduces the chance of introducing unrelated changes.

Addressing review comments using fixup commits

So you posted a PR and the maintainers aren't quite happy with it. Here are some guidelines to make the maintainers life easier and increase the chances that your PR will be reviewed swiftly.

1. Use fixup commits. When addressing reviewer feedback, you can create fixup commits. These commits mark your changes as corrections of specific previous commits in the PR.

Example:

git commit --fixup=<commit-hash>

This command creates a new commit that refers to an existing one, making it easier to rebase and squash later while showing reviewers the history of fixes. For extra points, link to the fixup commit in the thread where the change was requested.

2. After all requested changes were addressed, feel free to re-request a review. People might not notice that all changes were addressed.

3. Once the PR has been approved, rebase your PR to squash all the fixup commits, the autosquash option can help with this.

git rebase main --autosquash

Sign off

In order to have a concrete record that your contribution is intentional and you agree to license it under the same terms as the project's license, we've adopted the same lightweight approach that the Linux Kernel, Docker, and many other projects use: the DCO (Developer Certificate of Origin). This is a simple declaration that you wrote the contribution or otherwise have the right to contribute it to Matrix:

Developer Certificate of Origin
Version 1.1

Copyright (C) 2004, 2006 The Linux Foundation and its contributors.
660 York Street, Suite 102,
San Francisco, CA 94110 USA

Everyone is permitted to copy and distribute verbatim copies of this
license document, but changing it is not allowed.

Developer's Certificate of Origin 1.1

By making a contribution to this project, I certify that:

(a) The contribution was created in whole or in part by me and I
    have the right to submit it under the open source license
    indicated in the file; or

(b) The contribution is based upon previous work that, to the best
    of my knowledge, is covered under an appropriate open source
    license and I have the right under that license to submit that
    work with modifications, whether created in whole or in part
    by me, under the same open source license (unless I am
    permitted to submit under a different license), as indicated
    in the file; or

(c) The contribution was provided directly to me by some other
    person who certified (a), (b) or (c) and I have not modified
    it.

(d) I understand and agree that this project and the contribution
    are public and that a record of the contribution (including all
    personal information I submit with it, including my sign-off) is
    maintained indefinitely and may be redistributed consistent with
    this project or the open source license(s) involved.

If you agree to this for your contribution, then all that's needed is to include the line in your commit or pull request comment:

Signed-off-by: Your Name <[email protected]>

Git allows you to add this signoff automatically when using the -s flag to git commit, which uses the name and email set in your user.name and user.email git configs.

If you forgot to sign off your commits before making your pull request and are on Git 2.17+ you can mass signoff using rebase:

git rebase --signoff origin/main

Tips for working on the matrix-rust-sdk with specific IDEs

• RustRover will attempt to sync the project with all features enabled, causing an error in matrix-sdk ("only one of the features 'native-tls' or 'rustls-tls' can be enabled"). To work around this, open crates/matrix-sdk/Cargo.toml in RustRover and uncheck one of the native-tls or rustls-tls feature definitions: