Wednesday, January 26, 2011

Changes to illumos Contribution Process

First off, let me state that the following changes are aimed at both easing the challenging of contributing changes to illumos, while increasing our level of "confidence" in what changes are being integrated into our source code tree.

Up until now, illumos has used a contribution model that is primarily derived from the model used within Sun and Oracle for Solaris development.

This development model is based on the notion that all contributors have (or had at least) the direct ability to "push" code to the repository, after a certain number of review steps had been followed.

This model works well with a small team, or where all contributors are reasonably well trusted. This is also not typical at all of the way most FOSS projects work. (Indeed, with OpenSolaris, this model was not used for external contribution.)

Going forward, we want to enable a much wider group of developers, some of whom may not hang around long enough in our community to get a high level of "trust".

We also want to enable a contribution process that is more similar to what other FOSS projects use.

So, to this end, we are going to move from "developer push" to "advocate pull". "Advocates" are just our version of "maintainers" or "gatekeepers". (The Linux equivalent of this is Linus' "lieutenants".)

So now, rather than developers pushing changes directly to our mercurial tree, going forward Advocates will take patches from Contributors (either via hg export or patch file), verify that the content of the patch is what was reviewed, and will then be responsible for integrating those changes into our shared master.

Note that as part of this process, the Advocate will be ensuring that the original Contributor is still credited in the SCM change history. So Contributors still get credit for their work.

Also, we will still be insisting on other parts of the contribution process that we already have, such as code review, testing, and verification of legal right to receive the contribution.

The main implication for Contributors is that they can supply changes in the form of regular patches, which frees them from having to deal directly with one SCM or the other (more on that below). The other
implication is that if a merge conflict occurs that the Advocate can reject a change and ask the contributor to resolve the conflict and resubmit.

Note that this whole process is much much more similar to the process used by other big name open source projects, such as Linux.

At this point, I'd like to point out that we have a "clone" of illumos-gate on github. So you can use git if you want to. We also have an hg clone at bitbucket.

For now, Advocates use hg as our "master" repository, but we are also talking about a conversion to git to make life better. That's a more detailed topic of conversation, but mostly the concern about whether we are using git or hg should be irrelevant to contributors, as they can use either and are not directly exposed to the integration step (hg push or git push for example.)

The final tidbit here is that we need to set up a public page with a list of Advocates, but for now the list of illumos-gate Advocates is:

  • Garrett D'Amore
  • Albert Lee
  • Rich Lowe
  • Gordon Ross

As more people contribute and demonstrate a level of throughness and trustworthiness, I hope the above list will expand somewhat.

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