The Mesa 3D Graphics Library

Submitting patches

Basic guidelines

Patch formatting

Testing Patches

It should go without saying that patches must be tested. In general, do whatever testing is prudent.

You should always run the Mesa test suite before submitting patches. The test suite can be run using the 'make check' command. All tests must pass before patches will be accepted, this may mean you have to update the tests themselves.

Whenever possible and applicable, test the patch with Piglit and/or dEQP to check for regressions.

As mentioned at the begining, patches should be bisectable. A good way to test this is to make use of the `git rebase` command, to run your tests on each commit. Assuming your branch is based off origin/master, you can run:

$ git rebase --interactive --exec "make check" origin/master
replacing "make check" with whatever other test you want to run.

Mailing Patches

Patches should be sent to the mesa-dev mailing list for review: When submitting a patch make sure to use git send-email rather than attaching patches to emails. Sending patches as attachments prevents people from being able to provide in-line review comments.

When submitting follow-up patches you can use --in-reply-to to make v2, v3, etc patches show up as replies to the originals. This usually works well when you're sending out updates to individual patches (as opposed to re-sending the whole series). Using --in-reply-to makes it harder for reviewers to accidentally review old patches.

When submitting follow-up patches you should also login to patchwork and change the state of your old patches to Superseded.

Some companies' mail server automatically append a legal disclaimer, usually containing something along the lines of "The information in this email is confidential" and "distribution is strictly prohibited".
These legal notices prevent us from being able to accept your patch, rendering the whole process pointless. Please make sure these are disabled before sending your patches. (Note that you may need to contact your email administrator for this.)

Reviewing Patches

When you've reviewed a patch on the mailing list, please be unambiguous about your review. That is, state either

    Reviewed-by: Joe Hacker <>
    Acked-by: Joe Hacker <>

Rather than saying just "LGTM" or "Seems OK".

If small changes are suggested, it's OK to say something like:

   With the above fixes, Reviewed-by: Joe Hacker <>

which tells the patch author that the patch can be committed, as long as the issues are resolved first.

Nominating a commit for a stable branch

There are three ways to nominate a patch for inclusion in the stable branch and release.

Note: resending patch identical to one on mesa-dev@ or one that differs only by the extra mesa-stable@ tag is not recommended.

The stable tag

If you want a commit to be applied to a stable branch, you should add an appropriate note to the commit message.

Here are some examples of such a note:

Simply adding the CC to the mesa-stable list address is adequate to nominate the commit for all the active stable branches. If the commit is not applicable for said branch the stable-release manager will reply stating so. This "CC" syntax for patch nomination will cause patches to automatically be copied to the mesa-stable@ mailing list when you use "git send-email" to send patches to the mesa-dev@ mailing list. If you prefer using --suppress-cc that won't have any negative effect on the patch nomination.

Note: by removing the tag [as the commit is pushed] the patch is explicitly rejected from inclusion in the stable branch(es).
Thus, drop the line only if you want to cancel the nomination.

Alternatively, if one uses the "Fixes" tag as described in the "Patch formatting" section, it nominates a commit for all active stable branches that include the commit that is referred to.

Criteria for accepting patches to the stable branch

Mesa has a designated release manager for each stable branch, and the release manager is the only developer that should be pushing changes to these branches. Everyone else should nominate patches using the mechanism described above. The following rules define which patches are accepted and which are not. The stable-release manager is also given broad discretion in rejecting patches that have been nominated. If the patch complies with the rules it will be cherry-picked. Alternatively the release manager will reply to the patch in question stating why the patch has been rejected or would request a backport. A summary of all the picked/rejected patches will be presented in the pre-release announcement. The stable-release manager may at times need to force-push changes to the stable branches, for example, to drop a previously-picked patch that was later identified as causing a regression). These force-pushes may cause changes to be lost from the stable branch if developers push things directly. Consider yourself warned.

Sending backports for the stable branch

By default merge conflicts are resolved by the stable-release manager. In which case he/she should provide a comment about the changes required, alongside the Conflicts section. Summary of which will be provided in the pre-release announcement.
Developers are interested in sending backports are recommended to use either a [BACKPORT #branch] subject prefix or provides similar information within the commit summary.

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