types/CONTRIBUTING.md

Welcome! Thanks for looking into contributing to our project!

Table of Contents

• Looking for Help?
  • Documentation
  • Chat Rooms
• Reporting Issues
• Submitting Code
  • Coding Style
  • Modifying Endpoints
  • Submitting PRs
  • Where do I start?
• Testing
• Contact

Looking for Help?

Here is a list of helpful resources you can consult:

Documentation

• Matrix spec Documentation

Chat Rooms

• Ruma Matrix room: #ruma:matrix.org
• Ruma Development Matrix room: #ruma-dev:matrix.org
• Matrix Developer room: #matrix-dev:matrix.org

Reporting Issues

If you find any bugs, inconsistencies or other problems, feel free to submit a GitHub issue.

If you have a quick question, it may be easier to leave a message in #ruma:matrix.org.

Also, if you have trouble getting on board, let us know so we can help future contributors to the project overcome that hurdle too.

Submitting Code

Ready to write some code? Great! Here are some guidelines to follow to help you on your way:

Coding Style

In general, try to replicate the coding style that is already present. Specifically:

Naming

For internal consistency, ruma uses American spelling for variable names. Actual values may differ, as the matrix specification has a mix of British and American English.

Common Types

When writing endpoint definitions, use the following mapping from request / response field types listed in the specification to Rust types:

Specification type	Rust type
boolean	bool
integer	js_int::UInt (unless denoted as signed, then js_int::Int)
string	If for an identifier (e.g. user ID, room ID), use one of the types from ruma-identifiers. Otherwise, use String.
object	serde_json::Value
[…]	Vec<…>
{string: …}	BTreeMap<String, …> (or BTreeMap<SomeId, …>)

Code Formatting and Linting

We use rustfmt to ensure consistent formatting code and clippy to catch common mistakes not caught by the compiler as well as enforcing a few custom code style choices.

# if you don't have them installed, install or update the nightly toolchain
rustup install nightly
# … and install prebuilt rustfmt and clippy executables (available for most platforms)
rustup component add rustfmt clippy

Before committing your changes, run cargo +nightly fmt to format the code (if your editor / IDE isn't set up to run it automatically) and cargo +nightly clippy --workspace¹ to run lints.

You can also run all of the tests the same way CI does through cargo xtask ci. This will take a while to complete since it runs all of the tests on stable Rust, formatting and lint checks on nightly Rust, as well as some basic checks on our minimum supported Rust version. It requires [rustup] to be installed and the toolchains for those three versions to be set up (in case of a missing toolchain, rustup will tell you what to do though). There are also cargo xtask ci stable|nightly|msrv subcommands for only running one of the CI jobs.

¹ If you modified feature-gated code (#[cfg(feature = "something")]), you have to pass --all-features or --features something to clippy for it to check that code

(Type) Privacy and Forwards Compatibility

Generally, all structs that are mirroring types defined in the Matrix specification should have all their fields public. Where there are restrictions to the fields value beyond their type, these should generally be implemented by creating or using a more constrained type than the spec uses for that field – for example, we have a number of identifier types but the Matrix spec uses string for fields that hold user IDs / room IDs and so on.

Almost all types in ruma-common and the API crates use the #[non_exhaustive] attribute, to allow us to adapt to new minor releases of the Matrix specification without having a major release of our crates. You can generally just apply #[non_exhaustive] to everything – it's a backwards compatible change to remove it in the rare case it is not warranted.

Due to this combination of public fields and non-exhaustiveness, all structs generally need a constructor function or From / TryFrom implementation to be able to create them in a straight-forward way (always going through Deserialize would be quite ugly).

Import Formatting

Organize your imports into three groups separated by blank lines:

1. std imports
2. External imports (from other crates)
3. Local imports (self::, super::, crate:: and things like LocalEnum::*)

For example,

use std::collections::BTreeMap;

use ruma_common::api::ruma_api;

use super::MyType;

Commit Messages

Write commit messages using the imperative mood, as if completing the sentence: "If applied, this commit will ___." For example, use "Fix some bug" instead of "Fixed some bug" or "Add a feature" instead of "Added a feature".

(Take a look at this blog post for more information on writing good commit messages.)

Modifying Endpoints

Matrix Spec Version

Use the latest v1.x documentation when adding or modifying code. We target the latest minor version of the Matrix specification.

Endpoint Module Structure

Matrix uses versioned endpoints (with a few small exceptions), we follow this versioning approach in modules as well.

We structure endpoints and their versions like the following;

endpoint_name::v1

All bits pertaining a specific version (that can be linked to in the spec) reside in such a module, some bits may be shared between endpoint versions, but this should be handled on a case-by-case basis.

Endpoint files may have their version modules embedded;

// endpoint_name.rs

mod v1 {
  // (version-specific stuff)
}

This happens if the endpoint either has a single version, or a few versions of sufficiently small size.

Endpoint Documentation Header

Add a comment to the top of each endpoint file that includes the path and a link to the documentation of the spec. Replace the version marker (v3) with a *, like so;

//! `GET /_matrix/client/*/sync`

Then, in the subsequent version module, embed the version and specification link like so;

pub mod v3 {
    //! `/v3/` ([spec])
    //!
    //! [spec]: https://spec.matrix.org/v1.2/client-server-api/#get_matrixclientv3sync
}

Naming Endpoints

When adding new endpoints, select the module that fits the purpose of the endpoint. When naming the endpoint itself, you can use the following guidelines:

• The name should be a verb describing what the client is requesting, e.g. get_some_resource.
• Endpoints which are basic CRUD operations should use the prefixes create, get, update, and delete.
• The prefix set is preferred to create if the resource is a singleton. In other words, when there's no distinction between create and update.
• Try to use names that are as descriptive as possible and distinct from other endpoints in all other modules. (For example, instead of r0::room::get_event, use r0::room::get_room_event).
• If you're not sure what to name it, pick any name and we can help you with it.

Borrowing Request Types

In order to reduce the number of .clone()s necessary to send requests to a server, we support borrowed types for request types. (We hope to support borrowing in response types sometime, but that is dependent on GATs.)

Types to borrow

Field type	Borrowed type	Notes
strings	&'a str
identifiers	&'a IdentifierType
Vec<_>	&'a [_]	The inner type should not be borrowed.

Types not to borrow

Inner types of Vecs should not be borrowed, nor should BTreeMaps and such.

Structs also should not be borrowed, with the exception that if a struct:

• has fields that should be borrowed according to the table above (strings, identifiers, Vecs), and
• is only used inside request blocks (i.e. not in response blocks or in events),

then the struct should be lifetime-parameterized and apply the same rules to their fields. So instead of

ruma_api! {
    request: {
        my_field: MyStruct,
    }
    // ...
}

pub struct MyStruct {
    inner_string_field: String,
}

use

ruma_api! {
    request: {
        my_field: MyStruct<'a>,
    }
    // ...
}

pub struct MyStruct<'a> {
    inner_string_field: &'a str,
}

Tracking Changes

If your changes affect the API of a user-facing crate (all except the -macros crates and ruma-identifiers-validation), add an entry about them to the change log (CHANGELOG.md) of that crate. Where applicable, try to find and denote the version of the spec that included the change you are making.

Submitting PRs

Once you're ready to submit your code, create a pull request, and one of our maintainers will review it. Once your PR has passed review, a maintainer will merge the request and you're done! 🎉

Where do I start?

If this is your first contribution to the project, we recommend taking a look at one of the open issues we've marked for new contributors.

Testing

Before committing, run cargo check to make sure that your changes can build, as well as running the formatting and linting tools mentioned above.