As the Haskell community has grown, and emphasis on development has moved from language to libraries, the need for a more formalised process for contributing to libraries has emerged. This page documents our 'best practices' for proposing changes to library interfaces (e.g. new modules or functions, removing functions), especially for modules in the base package.
In essence, we don't want proposals to go unnoticed, but changes to basic interfaces also need thorough consideration.
Under the old ad hoc system, unless a proposal meets with a chorus of approval, the only way to get a decision is from SimonM or unilateral action by some committer. This slowed development.
Creating a proposal
In order to ensure we have something concrete to discuss, please follow the following guidelines:
- Currency. Make your changes against a copy of the HEAD branch of the relevant library, and make sure it compiles.
- Portability. Code should be portable. If it is not portable, reasons should be given. At the very least ensure the code runs in Hugs and GHC, and on Windows and Linux.
- Style. Follow the conventions in the library you are modifying.
- Documentation. It must include valid Haddock documentation.
- Tests. Code should also come with tests for the testsuite.
- Pure code should also come with QuickCheck properties.
- Impure code should have unit tests.
- We're working on a framework for the library tests.
Submitting the proposal
- Patch. Create a darcs patch of your change using darcs record, including a rationale for the change. Save the patch to a file, using darcs send --output.
- Tracking. Add a Trac ticket of type proposal for the appropriate library component, with a timescale for consideration (to focus the community's attention for a limited period), adding the patch file as an attachment.
- Submission. Send an email containing the Trac ticket number and description to email@example.com. (In the future this should happen when you record the ticket, but we haven't set it up yet.)
If someone has done all this, they are entitled to expect feedback; silence during the discussion period can be interpreted as consent.
Here are the proposals currently under consideration.
At the end of the discussion period
- Add to the ticket a summary of the relevant parts of the discussion. (The summary is needed for anyone wondering about the change later: it's not reasonable to point people at a 50-message thread.)
- If consensus was achieved, revise the patch as necessary, including the Trac ticket number, and commit it (or get someone to commit it for you).
- Close the ticket (usually as fixed or wontfix).
A deeply held disagreement at this point may require some form of government (voting, dictatorship, etc). This should be a rare event.
Here are the archived past proposals.
Here is an example of how to summarise a successful submission.
- GHC Working Conventions, including guidelines for submitting patches via darcs.
- Notes on programming style