7 - Patches should not mix code changes with code formatting changes
8 (except, perhaps, in very trivial cases.)
9 - Code patches should follow Mesa `coding
10 conventions <codingstyle.rst>`__.
11 - Whenever possible, patches should only affect individual Mesa/Gallium
13 - Patches should never introduce build breaks and should be bisectable
15 - Patches should be properly `formatted <#formatting>`__.
16 - Patches should be sufficiently `tested <#testing>`__ before
18 - Patches should be `submitted <#submit>`__ via a merge request for
19 `review <#reviewing>`__.
26 - Lines should be limited to 75 characters or less so that git logs
27 displayed in 80-column terminals avoid line wrapping. Note that git
28 log uses 4 spaces of indentation (4 + 75 < 80).
29 - The first line should be a short, concise summary of the change
30 prefixed with a module name. Examples:
34 mesa: Add support for querying GL_VERTEX_ATTRIB_ARRAY_LONG
36 gallium: add PIPE_CAP_DEVICE_RESET_STATUS_QUERY
38 i965: Fix missing type in local variable declaration.
40 - Subsequent patch comments should describe the change in more detail,
41 if needed. For example:
45 i965: Remove end-of-thread SEND alignment code.
47 This was present in Eric's initial implementation of the compaction code
48 for Sandybridge (commit 077d01b6). There is no documentation saying this
49 is necessary, and removing it causes no regressions in piglit on any
52 - A "Signed-off-by:" line is not required, but not discouraged either.
53 - If a patch addresses an issue in gitlab, use the Closes: tag For
58 Closes: https://gitlab.freedesktop.org/mesa/mesa/-/issues/1
60 Prefer the full url to just ``Closes: #1``, since the url makes it
61 easier to get to the bug page from ``git log``
63 **Do not use the ``Fixes:`` tag for this!** Mesa already uses
64 ``Fixes:`` for something else.
65 See `below <#fixes>`__.
67 - If there have been several revisions to a patch during the review
68 process, they should be noted such as in this example:
72 st/mesa: add ARB_texture_stencil8 support (v4)
74 if we support stencil texturing, enable texture_stencil8
75 there is no requirement to support native S8 for this,
76 the texture can be converted to x24s8 fine.
78 v2: fold fixes from Marek in:
79 a) put S8 last in the list
80 b) fix renderable to always test for d/s renderable
81 fixup the texture case to use a stencil only format
82 for picking the format for the texture view.
83 v3: hit fallback for getteximage
84 v4: put s8 back in front, it shouldn't get picked now (Ilia)
86 - If someone tested your patch, document it with a line like this:
90 Tested-by: Joe Hacker <jhacker@foo.com>
92 - If the patch was reviewed (usually the case) or acked by someone,
93 that should be documented with:
97 Reviewed-by: Joe Hacker <jhacker@foo.com>
98 Acked-by: Joe Hacker <jhacker@foo.com>
100 - When updating a merge request add all the tags (``Acked-by:``, ``Reviewed-by:``,
101 ``Fixes:``, ``Cc: mesa-stable`` and/or other) to the commit messages.
102 This provides reviewers with quick feedback if the patch has already
110 If a patch addresses a issue introduced with earlier commit, that
111 should be noted in the commit message. For example::
113 Fixes: d7b3707c612 "util/disk_cache: use stat() to check if entry is a directory"
115 You can produce those fixes lines by running this command once::
117 git config --global alias.fixes "show -s --pretty='format:Fixes: %h (\"%s\")'"
119 After that, using ``git fixes <sha1>`` will print the full line for you.
124 If you want a commit to be applied to a stable branch, you should add an
125 appropriate note to the commit message.
127 Using a ``Fixes:`` tag as described in `Patch formatting <#formatting>`__
128 is the preferred way to nominate a commit that should be backported.
129 There are scripts that will figure out which releases to apply the patch
130 to automatically, so you don't need to figure it out.
132 Alternatively, you may use a "CC:" tag. Here are some examples of such a
135 CC: 20.0 19.3 <mesa-stable>
137 Using the CC tag **should** include the stable branches you want to
138 nominate the patch to. If you do not provide any version it is nominated
139 to all active stable branches.
146 It should go without saying that patches must be tested. In general, do
147 whatever testing is prudent.
149 You should always run the Mesa test suite before submitting patches. The
150 test suite can be run using the 'meson test' command. All tests must
151 pass before patches will be accepted, this may mean you have to update
152 the tests themselves.
154 Whenever possible and applicable, test the patch with
155 `Piglit <https://piglit.freedesktop.org>`__ and/or
156 `dEQP <https://android.googlesource.com/platform/external/deqp/>`__ to
157 check for regressions.
159 As mentioned at the beginning, patches should be bisectable. A good way
160 to test this is to make use of the \`git rebase\` command, to run your
161 tests on each commit. Assuming your branch is based off
162 ``origin/master``, you can run:
166 $ git rebase --interactive --exec "meson test -C build/" origin/master
168 replacing ``"meson test"`` with whatever other test you want to run.
175 Patches are submitted to the Mesa project via a
176 `GitLab <https://gitlab.freedesktop.org/mesa/mesa>`__ Merge Request.
178 Add labels to your MR to help reviewers find it. For example:
180 - Mesa changes affecting all drivers: mesa
181 - Hardware vendor specific code: amd, intel, nvidia, ...
182 - Driver specific code: anvil, freedreno, i965, iris, radeonsi, radv,
184 - Other tag examples: gallium, util
186 Tick the following when creating the MR. It allows developers to rebase
187 your work on top of master.
191 Allow commits from members who can merge to the target branch
193 If you revise your patches based on code review and push an update to
194 your branch, you should maintain a **clean** history in your patches.
195 There should not be "fixup" patches in the history. The series should be
196 buildable and functional after every commit whenever you push the
199 It is your responsibility to keep the MR alive and making progress, as
200 there are no guarantees that a Mesa dev will independently take interest
205 - Make changes and update your branch based on feedback
206 - After an update, for the feedback you handled, close the feedback
207 discussion with the "Resolve Discussion" button. This way the
208 reviewers know which feedback got handled and which didn't.
209 - Old, stale MR may be closed, but you can reopen it if you still want
210 to pursue the changes
211 - You should periodically check to see if your MR needs to be rebased
212 - Make sure your MR is closed if your patches get pushed outside of
214 - Please send MRs from a personal fork rather than from the main Mesa
215 repository, as it clutters it unnecessarily.
222 To participate in code review, you can monitor the GitLab Mesa `Merge
223 Requests <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests>`__
224 page, and/or register for notifications in your gitlab settings.
226 When you've reviewed a patch, please be unambiguous about your review.
227 That is, state either
231 Reviewed-by: Joe Hacker <jhacker@foo.com>
237 Acked-by: Joe Hacker <jhacker@foo.com>
239 Rather than saying just "LGTM" or "Seems OK".
241 If small changes are suggested, it's OK to say something like:
245 With the above fixes, Reviewed-by: Joe Hacker <jhacker@foo.com>
247 which tells the patch author that the patch can be committed, as long as
248 the issues are resolved first.
250 These Reviewed-by, Acked-by, and Tested-by tags should also be amended
251 into commits in a MR before it is merged.
253 When providing a Reviewed-by, Acked-by, or Tested-by tag in a gitlab MR,
254 enclose the tag in backticks:
258 `Reviewed-by: Joe Hacker <jhacker@example.com>`
260 This is the markdown format for literal, and will prevent gitlab from
261 hiding the < and > symbols.
263 Review by non-experts is encouraged. Understanding how someone else goes
264 about solving a problem is a great way to learn your way around the
265 project. The submitter is expected to evaluate whether they have an
266 appropriate amount of review feedback from people who also understand
267 the code before merging their patches.
269 Nominating a commit for a stable branch
270 ---------------------------------------
272 There are several ways to nominate a patch for inclusion in the stable
273 branch and release. In order or preference:
275 - By adding the ``Fixes:`` tag in the commit message as described above, if you are fixing
277 - By adding the ``Cc: mesa-stable`` tag in the commit message as described above.
278 - By submitting a merge request against the ``staging/year.quarter``
281 Please **DO NOT** send patches to mesa-stable@lists.freedesktop.org, it
282 is not monitored actively and is a historical artifact.
284 If you are not the author of the original patch, please Cc: them in your
287 The current patch status can be observed in the `staging
288 branch <releasing.rst#stagingbranch>`__.
292 Criteria for accepting patches to the stable branch
293 ---------------------------------------------------
295 Mesa has a designated release manager for each stable branch, and the
296 release manager is the only developer that should be pushing changes to
297 these branches. Everyone else should nominate patches using the
298 mechanism described above. The following rules define which patches are
299 accepted and which are not. The stable-release manager is also given
300 broad discretion in rejecting patches that have been nominated.
302 - Patch must conform with the `Basic guidelines <#guidelines>`__
303 - Patch must have landed in master first. In case where the original
304 patch is too large and/or otherwise contradicts with the rules set
305 within, a backport is appropriate.
306 - It must not introduce a regression - be that build or runtime wise.
309 If the regression is due to faulty piglit/dEQP/CTS/other test
310 the latter must be fixed first. A reference to the offending test(s)
311 and respective fix(es) should be provided in the nominated patch.
313 - Patch cannot be larger than 100 lines.
314 - Patches that move code around with no functional change should be
316 - Patch must be a bug fix and not a new feature.
319 An exception to this rule, are hardware-enabling "features". For
320 example, `backports <#backports>`__ of new code to support a
321 newly-developed hardware product can be accepted if they can be
322 reasonably determined not to have effects on other hardware.
324 - Patch must be reviewed, For example, the commit message has
325 Reviewed-by, Signed-off-by, or Tested-by tags from someone but the
327 - Performance patches are considered only if they provide information
328 about the hardware, program in question and observed improvement. Use
329 numbers to represent your measurements.
331 If the patch complies with the rules it will be
332 `cherry-picked <releasing.rst#pickntest>`__. Alternatively the release
333 manager will reply to the patch in question stating why the patch has
334 been rejected or would request a backport. The stable-release manager
335 may at times need to force-push changes to the stable branches, for
336 example, to drop a previously-picked patch that was later identified as
337 causing a regression). These force-pushes may cause changes to be lost
338 from the stable branch if developers push things directly. Consider
343 Sending backports for the stable branch
344 ---------------------------------------
346 By default merge conflicts are resolved by the stable-release manager.
347 The release maintainer should resolve trivial conflicts, but for complex
348 conflicts they should ask the original author to provide a backport or
349 de-nominate the patch.
351 For patches that either need to be nominated after they've landed in
352 master, or that are known ahead of time to not not apply cleanly to a
353 stable branch (such as due to a rename), using a gitlab MR is most
354 appropriate. The MR should be based on and target the
355 staging/year.quarter branch, not on the year.quarter branch, per the
356 stable branch policy. Assigning the MR to release maintainer for said
357 branch or mentioning them is helpful, but not required.
362 - ``git rebase -i ...`` is your friend. Don't be afraid to use it.
363 - Apply a fixup to commit FOO.
365 .. code-block:: console
368 git commit --fixup=FOO
369 git rebase -i --autosquash ...
371 - Test for build breakage between patches e.g last 8 commits.
373 .. code-block:: console
375 git rebase -i --exec="ninja -C build/" HEAD~8