daml/CONTRIBUTING.md

# Contributing to Daml

Welcome! This page gives a high-level overview of how to contribute to the development of Daml.

There are many ways you can contribute beyond coding. For example, you can report problems, clarify [issues](https://github.com/digital-asset/daml/issues), and write documentation. If you're completely new to open source development, the [Open Source Guides](https://opensource.guide) is a great place to start.

## Working on the codebase

For information on how to build, test, and work on the codebase, see ["Contributing to Daml" in the README](./README.md#contributing-to-daml).

## Code of conduct

This project and everyone participating in it is governed by the [Daml Code of Conduct](./CODE_OF_CONDUCT.md). By participating, you are expected to uphold this code. Please report unacceptable behavior to [community@digitalasset.com](mailto:community@digitalasset.com).

## Git conventions

For Git commit messages, our principle is that `git log --pretty=oneline` should give readers a clear idea of what has changed and the detailed descriptions should help them understand the rationale. To achieve this:

* Commits must have a concise, imperative title, e.g.:
  * *Fix performance regression in …*
  * *Improve explanation of …*
  * *Remove module X because it is not used.*
* Commits should have a description that concisely explains the rationale and context for the change if that is not obvious.
* Commit descriptions should include a `Fixes #XX` line indicating what GitHub issue number the commit fixes.
* The git logs are not intended for user-facing change logs, but should be a useful reference when writing them.

## Pull request checklist

* Read this document (contribution guidelines).
* Does your PR include appropriate tests?
* Make sure your PR title and description makes it easy for other developers to understand what the contained commits do. The title should say what the changes do. The description should expand on what it does (if not obvious from the title alone), and say why it is being done.
* If your PR corresponds to an issue, add “Fixes #XX” to your pull request description. This will auto-close the corresponding issue when the commit is merged into main and tie the PR to the issue.
* the squashed commit for the PR **MUST** include in its body a section between the ``CHANGELOG_BEGIN`` and ``CHANGELOG_END`` tags. This section **MAY** include a list of _user-facing_ changes [Follow these guidelines on how to write a good changelog entry](#writing-a-good-changelog-entry).

The following is an example of a well-formed commit, including the description (first line) and a body that includes changelog additions:

      Fixes #1311

      Also fixes a typo in the Scala bindings documentation.

      CHANGELOG_BEGIN

      - [Sandbox] Introduced a new API for package management.
        See `#1311 <https://github.com/digital-asset/daml/issues/1311>`__.

      CHANGELOG_END

If you want to amend an existing changelog entry part of a PR already merged on main, do so by adding a ``WARNING`` to your changelog additions:

      CHANGELOG_BEGIN

      WARNING: replace existing changelog entry "Introduced a new API for package management" with the following.

      - [Sandbox] Introduce a new API for party management.
      See `#1311 <https://github.com/digital-asset/daml/issues/1311>`__.

      CHANGELOG_END

If the PR contains no _user-facing_ change, the section **MUST** be there but can be left empty, as in the following example:

      Fixes #6666

      Improve contribution guidelines

      CHANGELOG_BEGIN
      CHANGELOG_END

If you want to verify the changelog entries as described by a range of Git revisions, you can use the `unreleased.sh` script. In most cases, to see the entries added as part of commits added since branching off of `main`, you can run:

    ./unreleased.sh main..

## Writing a good changelog entry

Writing good changelog entries is **important**: as a developer, it gives visibility on your contribution; as a user, it makes clear what is new, what's changed, and how to deal with them, making the product more accessible and your work more meaningful.

The raw changelog is used to compile a meaningful summary of changes across releases. This happens some time after the PR has been merged and the person taking the responsibility of summarizing new user-facing features must be in the position to easily understand the nature of the change and report it. The ideal changelog entry can be more or less incorporated verbatim in the release notes.

Here are a few practical tips:

* if there are no user-facing changes, keep the changelog entry list empty
* the first term to appear should be the affected component -- [here's a list](#list-of-components-for-changelog-entries)
* write as many changelog entries as necessary
* don't be _too_ succinct: a single entry does **not have to** fit on a single line
* on the other end, if the size grows beyond 5-6 lines, rather add a link to a relevant documentation or issue with more details
* the ultimate target are end users: focus on the impact on them, tell them what's new or how to deal with a change

### List of components for changelog entries

This list should cover the vast majority of needs. If unsure, ask on the relevant GitHub issue or PR.

  * Daml Compiler
  * Daml on SQL
  * Daml Studio
  * Distribution/Releases
  * Extractor
  * Java Bindings
  * Java Codegen
  * JavaScript Client Libraries
  * JavaScript Codegen
  * JSON API
  * Ledger API Specification
  * Integration Kit †
  * Navigator
  * Daml REPL
  * Sandbox
  * Scala Bindings
  * Scala Codegen
  * Daml Script
  * Daml Assistant
  * Daml Standard Library
  * Daml Triggers

† Covers the Ledger API Test Tool and changes to libraries that affect ledger integrations (e.g. `kvutils`)

## Working with issues

We use issues and [pull requests](https://help.github.com/articles/about-pull-requests/) to collaborate and track our work. Anyone is welcome to open an issue. If you just want to ask a question, please ask away on [the Daml forum](https://discuss.daml.com).

We encourage everyone to vote on issues that they support or not:

* 👍 - upvote
* 👎 - downvote

When you start working on an issue, we encourage you to tell others about it in an issue comment. If other contributors know that this issue is already being worked on, they might decide to tackle another issue instead.

When you add `TODO` (nice to have) and `FIXME` (should fix) comments in the code, we encourage you to create a corresponding issue and reference it as follows:

* `TODO(#XX): <description>` where `#XX` corresponds to the GitHub issue.
* `FIXME(#XX): <description>` where `#XX` corresponds to the GitHub issue.

### Labels

We use labels to indicate what component the issue relates to (`component/...`). We use some special labels:

- `broken` to indicate that something in the repo is seriously broken and needs to be fixed.
- `discussion` to indicate the issue is to discuss and decide on something.
- `good-first-issue` to indicate that the issue is suitable for those who want to contribute but don't know where to start.

By default, issues represent "work to be done" -- that might be features, improvements, non-critical bug fixes, and so on.

The Daml Language team uses labels to indicate priority (the Daml Runtime team does not):

- `language/now`
- `language/soon`
- `language/later`

You can see all labels [here](https://github.com/digital-asset/daml/labels).

### Milestones

In addition to labels, we group issues into *milestones*. The Daml Language team has all issues in a single *Language* milestone; the Daml Runtime team uses them to group work efforts (*Add PostgreSQL backend to the Ledger* for example). *Maintenance* and *Backlog* are special milestones.

Issues without a milestone are treated as in need of triaging.

You can see all the active milestones [here](https://github.com/digital-asset/daml/milestones).

## Discussions

Please hold discussions that are relevant to Daml development and not confidential in GitHub issues. That way, anyone who wants to contribute or follow along can do so. If you have private discussions, please summarise them in an issue or comment to an issue.

You can also join a `#daml-contributors` channel on our Slack: [damldriven.slack.com](https://damldriven.slack.com/sso/saml/start).

# Thank you!

Thank you for taking the time to contribute!