9 - Patches should not mix code changes with code formatting changes
10 (except, perhaps, in very trivial cases.)
11 - Code patches should follow Mesa :doc:`coding
12 conventions <codingstyle>`.
13 - Whenever possible, patches should only affect individual Mesa/Gallium
15 - Patches should never introduce build breaks and should be bisectable
17 - Patches should be properly `formatted <#formatting>`__.
18 - Patches should be sufficiently `tested <#testing>`__ before
20 - Patches should be `submitted <#submit>`__ via a merge request for
21 `review <#reviewing>`__.
28 - Lines should be limited to 75 characters or less so that git logs
29 displayed in 80-column terminals avoid line wrapping. Note that git
30 log uses 4 spaces of indentation (4 + 75 < 80).
31 - The first line should be a short, concise summary of the change
32 prefixed with a module name. Examples:
36 mesa: Add support for querying GL_VERTEX_ATTRIB_ARRAY_LONG
38 gallium: add PIPE_CAP_DEVICE_RESET_STATUS_QUERY
40 i965: Fix missing type in local variable declaration.
42 - Subsequent patch comments should describe the change in more detail,
43 if needed. For example:
47 i965: Remove end-of-thread SEND alignment code.
49 This was present in Eric's initial implementation of the compaction code
50 for Sandybridge (commit 077d01b6). There is no documentation saying this
51 is necessary, and removing it causes no regressions in piglit on any
54 - A "Signed-off-by:" line is not required, but not discouraged either.
55 - If a patch addresses an issue in gitlab, use the Closes: tag For
60 Closes: https://gitlab.freedesktop.org/mesa/mesa/-/issues/1
62 Prefer the full url to just ``Closes: #1``, since the url makes it
63 easier to get to the bug page from ``git log``
65 **Do not use the ``Fixes:`` tag for this!** Mesa already uses
66 ``Fixes:`` for something else.
67 See `below <#fixes>`__.
69 - If there have been several revisions to a patch during the review
70 process, they should be noted such as in this example:
74 st/mesa: add ARB_texture_stencil8 support (v4)
76 if we support stencil texturing, enable texture_stencil8
77 there is no requirement to support native S8 for this,
78 the texture can be converted to x24s8 fine.
80 v2: fold fixes from Marek in:
81 a) put S8 last in the list
82 b) fix renderable to always test for d/s renderable
83 fixup the texture case to use a stencil only format
84 for picking the format for the texture view.
85 v3: hit fallback for getteximage
86 v4: put s8 back in front, it shouldn't get picked now (Ilia)
88 - If someone tested your patch, document it with a line like this:
92 Tested-by: Joe Hacker <jhacker@foo.com>
94 - If the patch was reviewed (usually the case) or acked by someone,
95 that should be documented with:
99 Reviewed-by: Joe Hacker <jhacker@foo.com>
100 Acked-by: Joe Hacker <jhacker@foo.com>
102 - When updating a merge request add all the tags (``Acked-by:``, ``Reviewed-by:``,
103 ``Fixes:``, ``Cc: mesa-stable`` and/or other) to the commit messages.
104 This provides reviewers with quick feedback if the patch has already
112 If a patch addresses a issue introduced with earlier commit, that
113 should be noted in the commit message. For example::
115 Fixes: d7b3707c612 "util/disk_cache: use stat() to check if entry is a directory"
117 You can produce those fixes lines by running this command once::
119 git config --global alias.fixes "show -s --pretty='format:Fixes: %h (\"%s\")'"
121 After that, using ``git fixes <sha1>`` will print the full line for you.
126 If you want a commit to be applied to a stable branch, you should add an
127 appropriate note to the commit message.
129 Using a ``Fixes:`` tag as described in `Patch formatting <#formatting>`__
130 is the preferred way to nominate a commit that should be backported.
131 There are scripts that will figure out which releases to apply the patch
132 to automatically, so you don't need to figure it out.
134 Alternatively, you may use a "CC:" tag. Here are some examples of such a
137 CC: 20.0 19.3 <mesa-stable>
139 Using the CC tag **should** include the stable branches you want to
140 nominate the patch to. If you do not provide any version it is nominated
141 to all active stable branches.
148 It should go without saying that patches must be tested. In general, do
149 whatever testing is prudent.
151 You should always run the Mesa test suite before submitting patches. The
152 test suite can be run using the 'meson test' command. All tests must
153 pass before patches will be accepted, this may mean you have to update
154 the tests themselves.
156 Whenever possible and applicable, test the patch with
157 `Piglit <https://piglit.freedesktop.org>`__ and/or
158 `dEQP <https://android.googlesource.com/platform/external/deqp/>`__ to
159 check for regressions.
161 As mentioned at the beginning, patches should be bisectable. A good way
162 to test this is to make use of the \`git rebase\` command, to run your
163 tests on each commit. Assuming your branch is based off
164 ``origin/master``, you can run:
168 $ git rebase --interactive --exec "meson test -C build/" origin/master
170 replacing ``"meson test"`` with whatever other test you want to run.
177 Patches are submitted to the Mesa project via a
178 `GitLab <https://gitlab.freedesktop.org/mesa/mesa>`__ Merge Request.
180 Add labels to your MR to help reviewers find it. For example:
182 - Mesa changes affecting all drivers: mesa
183 - Hardware vendor specific code: amd, intel, nvidia, ...
184 - Driver specific code: anvil, freedreno, i965, iris, radeonsi, radv,
186 - Other tag examples: gallium, util
188 Tick the following when creating the MR. It allows developers to rebase
189 your work on top of master.
193 Allow commits from members who can merge to the target branch
195 If you revise your patches based on code review and push an update to
196 your branch, you should maintain a **clean** history in your patches.
197 There should not be "fixup" patches in the history. The series should be
198 buildable and functional after every commit whenever you push the
201 It is your responsibility to keep the MR alive and making progress, as
202 there are no guarantees that a Mesa dev will independently take interest
207 - Make changes and update your branch based on feedback
208 - After an update, for the feedback you handled, close the feedback
209 discussion with the "Resolve Discussion" button. This way the
210 reviewers know which feedback got handled and which didn't.
211 - Old, stale MR may be closed, but you can reopen it if you still want
212 to pursue the changes
213 - You should periodically check to see if your MR needs to be rebased
214 - Make sure your MR is closed if your patches get pushed outside of
216 - Please send MRs from a personal fork rather than from the main Mesa
217 repository, as it clutters it unnecessarily.
224 To participate in code review, you can monitor the GitLab Mesa `Merge
225 Requests <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests>`__
226 page, and/or register for notifications in your gitlab settings.
228 When you've reviewed a patch, please be unambiguous about your review.
229 That is, state either
233 Reviewed-by: Joe Hacker <jhacker@foo.com>
239 Acked-by: Joe Hacker <jhacker@foo.com>
241 Rather than saying just "LGTM" or "Seems OK".
243 If small changes are suggested, it's OK to say something like:
247 With the above fixes, Reviewed-by: Joe Hacker <jhacker@foo.com>
249 which tells the patch author that the patch can be committed, as long as
250 the issues are resolved first.
252 These Reviewed-by, Acked-by, and Tested-by tags should also be amended
253 into commits in a MR before it is merged.
255 When providing a Reviewed-by, Acked-by, or Tested-by tag in a gitlab MR,
256 enclose the tag in backticks:
260 `Reviewed-by: Joe Hacker <jhacker@example.com>`
262 This is the markdown format for literal, and will prevent gitlab from
263 hiding the < and > symbols.
265 Review by non-experts is encouraged. Understanding how someone else goes
266 about solving a problem is a great way to learn your way around the
267 project. The submitter is expected to evaluate whether they have an
268 appropriate amount of review feedback from people who also understand
269 the code before merging their patches.
271 Nominating a commit for a stable branch
272 ---------------------------------------
274 There are several ways to nominate a patch for inclusion in the stable
275 branch and release. In order or preference:
277 - By adding the ``Fixes:`` tag in the commit message as described above, if you are fixing
279 - By adding the ``Cc: mesa-stable`` tag in the commit message as described above.
280 - By submitting a merge request against the ``staging/year.quarter``
283 Please **DO NOT** send patches to mesa-stable@lists.freedesktop.org, it
284 is not monitored actively and is a historical artifact.
286 If you are not the author of the original patch, please Cc: them in your
289 The current patch status can be observed in the `staging
290 branch <releasing.rst#stagingbranch>`__.
294 Criteria for accepting patches to the stable branch
295 ---------------------------------------------------
297 Mesa has a designated release manager for each stable branch, and the
298 release manager is the only developer that should be pushing changes to
299 these branches. Everyone else should nominate patches using the
300 mechanism described above. The following rules define which patches are
301 accepted and which are not. The stable-release manager is also given
302 broad discretion in rejecting patches that have been nominated.
304 - Patch must conform with the `Basic guidelines <#guidelines>`__
305 - Patch must have landed in master first. In case where the original
306 patch is too large and/or otherwise contradicts with the rules set
307 within, a backport is appropriate.
308 - It must not introduce a regression - be that build or runtime wise.
311 If the regression is due to faulty piglit/dEQP/CTS/other test
312 the latter must be fixed first. A reference to the offending test(s)
313 and respective fix(es) should be provided in the nominated patch.
315 - Patch cannot be larger than 100 lines.
316 - Patches that move code around with no functional change should be
318 - Patch must be a bug fix and not a new feature.
321 An exception to this rule, are hardware-enabling "features". For
322 example, `backports <#backports>`__ of new code to support a
323 newly-developed hardware product can be accepted if they can be
324 reasonably determined not to have effects on other hardware.
326 - Patch must be reviewed, For example, the commit message has
327 Reviewed-by, Signed-off-by, or Tested-by tags from someone but the
329 - Performance patches are considered only if they provide information
330 about the hardware, program in question and observed improvement. Use
331 numbers to represent your measurements.
333 If the patch complies with the rules it will be
334 :ref:`cherry-picked <pickntest>`. Alternatively the release
335 manager will reply to the patch in question stating why the patch has
336 been rejected or would request a backport. The stable-release manager
337 may at times need to force-push changes to the stable branches, for
338 example, to drop a previously-picked patch that was later identified as
339 causing a regression). These force-pushes may cause changes to be lost
340 from the stable branch if developers push things directly. Consider
345 Sending backports for the stable branch
346 ---------------------------------------
348 By default merge conflicts are resolved by the stable-release manager.
349 The release maintainer should resolve trivial conflicts, but for complex
350 conflicts they should ask the original author to provide a backport or
351 de-nominate the patch.
353 For patches that either need to be nominated after they've landed in
354 master, or that are known ahead of time to not not apply cleanly to a
355 stable branch (such as due to a rename), using a gitlab MR is most
356 appropriate. The MR should be based on and target the
357 staging/year.quarter branch, not on the year.quarter branch, per the
358 stable branch policy. Assigning the MR to release maintainer for said
359 branch or mentioning them is helpful, but not required.
364 - ``git rebase -i ...`` is your friend. Don't be afraid to use it.
365 - Apply a fixup to commit FOO.
367 .. code-block:: console
370 git commit --fixup=FOO
371 git rebase -i --autosquash ...
373 - Test for build breakage between patches e.g last 8 commits.
375 .. code-block:: console
377 git rebase -i --exec="ninja -C build/" HEAD~8