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 Fixes for
66 - If a patch addresses a issue introduced with earlier commit, that
67 should be noted in the patch comment. For example:
71 Fixes: d7b3707c612 "util/disk_cache: use stat() to check if entry is a directory"
73 - You can produce those fixes lines by running
77 git config --global alias.fixes "show -s --pretty='format:Fixes: %h (\"%s\")'"
85 - If there have been several revisions to a patch during the review
86 process, they should be noted such as in this example:
90 st/mesa: add ARB_texture_stencil8 support (v4)
92 if we support stencil texturing, enable texture_stencil8
93 there is no requirement to support native S8 for this,
94 the texture can be converted to x24s8 fine.
96 v2: fold fixes from Marek in:
97 a) put S8 last in the list
98 b) fix renderable to always test for d/s renderable
99 fixup the texture case to use a stencil only format
100 for picking the format for the texture view.
101 v3: hit fallback for getteximage
102 v4: put s8 back in front, it shouldn't get picked now (Ilia)
104 - If someone tested your patch, document it with a line like this:
108 Tested-by: Joe Hacker <jhacker@foo.com>
110 - If the patch was reviewed (usually the case) or acked by someone,
111 that should be documented with:
115 Reviewed-by: Joe Hacker <jhacker@foo.com>
116 Acked-by: Joe Hacker <jhacker@foo.com>
118 - If sending later revision of a patch, add all the tags - ack, r-b,
119 Cc: mesa-stable and/or other. This provides reviewers with quick
120 feedback if the patch has already been reviewed.
127 It should go without saying that patches must be tested. In general, do
128 whatever testing is prudent.
130 You should always run the Mesa test suite before submitting patches. The
131 test suite can be run using the 'meson test' command. All tests must
132 pass before patches will be accepted, this may mean you have to update
133 the tests themselves.
135 Whenever possible and applicable, test the patch with
136 `Piglit <https://piglit.freedesktop.org>`__ and/or
137 `dEQP <https://android.googlesource.com/platform/external/deqp/>`__ to
138 check for regressions.
140 As mentioned at the beginning, patches should be bisectable. A good way
141 to test this is to make use of the \`git rebase\` command, to run your
142 tests on each commit. Assuming your branch is based off
143 ``origin/master``, you can run:
147 $ git rebase --interactive --exec "meson test -C build/" origin/master
149 replacing ``"meson test"`` with whatever other test you want to run.
156 Patches are submitted to the Mesa project via a
157 `GitLab <https://gitlab.freedesktop.org/mesa/mesa>`__ Merge Request.
159 Add labels to your MR to help reviewers find it. For example:
161 - Mesa changes affecting all drivers: mesa
162 - Hardware vendor specific code: amd, intel, nvidia, ...
163 - Driver specific code: anvil, freedreno, i965, iris, radeonsi, radv,
165 - Other tag examples: gallium, util
167 Tick the following when creating the MR. It allows developers to rebase
168 your work on top of master.
172 Allow commits from members who can merge to the target branch
174 If you revise your patches based on code review and push an update to
175 your branch, you should maintain a **clean** history in your patches.
176 There should not be "fixup" patches in the history. The series should be
177 buildable and functional after every commit whenever you push the
180 It is your responsibility to keep the MR alive and making progress, as
181 there are no guarantees that a Mesa dev will independently take interest
186 - Make changes and update your branch based on feedback
187 - After an update, for the feedback you handled, close the feedback
188 discussion with the "Resolve Discussion" button. This way the
189 reviewers know which feedback got handled and which didn't.
190 - Old, stale MR may be closed, but you can reopen it if you still want
191 to pursue the changes
192 - You should periodically check to see if your MR needs to be rebased
193 - Make sure your MR is closed if your patches get pushed outside of
195 - Please send MRs from a personal fork rather than from the main Mesa
196 repository, as it clutters it unnecessarily.
203 To participate in code review, you can monitor the GitLab Mesa `Merge
204 Requests <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests>`__
205 page, and/or register for notifications in your gitlab settings.
207 When you've reviewed a patch, please be unambiguous about your review.
208 That is, state either
212 Reviewed-by: Joe Hacker <jhacker@foo.com>
218 Acked-by: Joe Hacker <jhacker@foo.com>
220 Rather than saying just "LGTM" or "Seems OK".
222 If small changes are suggested, it's OK to say something like:
226 With the above fixes, Reviewed-by: Joe Hacker <jhacker@foo.com>
228 which tells the patch author that the patch can be committed, as long as
229 the issues are resolved first.
231 These Reviewed-by, Acked-by, and Tested-by tags should also be amended
232 into commits in a MR before it is merged.
234 When providing a Reviewed-by, Acked-by, or Tested-by tag in a gitlab MR,
235 enclose the tag in backticks:
239 `Reviewed-by: Joe Hacker <jhacker@example.com>`
241 This is the markdown format for literal, and will prevent gitlab from
242 hiding the < and > symbols.
244 Review by non-experts is encouraged. Understanding how someone else goes
245 about solving a problem is a great way to learn your way around the
246 project. The submitter is expected to evaluate whether they have an
247 appropriate amount of review feedback from people who also understand
248 the code before merging their patches.
250 Nominating a commit for a stable branch
251 ---------------------------------------
253 There are three ways to nominate a patch for inclusion in the stable
256 - By adding the Cc: mesa-stable@ tag as described below.
257 - By adding the fixes: tag as described below.
258 - By submitting a merge request against the "staging/year.quarter"
261 Please **DO NOT** send patches to mesa-stable@lists.freedesktop.org, it
262 is not monitored actively and is a historical artifact.
264 If you are not the author of the original patch, please Cc: them in your
267 The current patch status can be observed in the `staging
268 branch <releasing.rst#stagingbranch>`__.
273 If you want a commit to be applied to a stable branch, you should add an
274 appropriate note to the commit message.
276 Using a "fixes tag" as described in `Patch formatting <#formatting>`__
277 is the preferred way to nominate a commit that you know ahead of time
278 should be backported. There are scripts that will figure out which
279 releases to apply the patch to automatically, so you don't need to
282 Alternatively, you may use a "CC:" tag. Here are some examples of such a
287 CC: 20.0 19.3 <mesa-stable@lists.freedesktop.org>
289 Using the CC tag **should** include the stable branches you want to
290 nominate the patch to. If you do not provide any version it is nominated
291 to all active stable branches.
295 Criteria for accepting patches to the stable branch
296 ---------------------------------------------------
298 Mesa has a designated release manager for each stable branch, and the
299 release manager is the only developer that should be pushing changes to
300 these branches. Everyone else should nominate patches using the
301 mechanism described above. The following rules define which patches are
302 accepted and which are not. The stable-release manager is also given
303 broad discretion in rejecting patches that have been nominated.
305 - Patch must conform with the `Basic guidelines <#guidelines>`__
306 - Patch must have landed in master first. In case where the original
307 patch is too large and/or otherwise contradicts with the rules set
308 within, a backport is appropriate.
309 - It must not introduce a regression - be that build or runtime wise.
312 If the regression is due to faulty piglit/dEQP/CTS/other test
313 the latter must be fixed first. A reference to the offending test(s)
314 and respective fix(es) should be provided in the nominated patch.
316 - Patch cannot be larger than 100 lines.
317 - Patches that move code around with no functional change should be
319 - Patch must be a bug fix and not a new feature.
322 An exception to this rule, are hardware-enabling "features". For
323 example, `backports <#backports>`__ of new code to support a
324 newly-developed hardware product can be accepted if they can be
325 reasonably determined not to have effects on other hardware.
327 - Patch must be reviewed, For example, the commit message has
328 Reviewed-by, Signed-off-by, or Tested-by tags from someone but the
330 - Performance patches are considered only if they provide information
331 about the hardware, program in question and observed improvement. Use
332 numbers to represent your measurements.
334 If the patch complies with the rules it will be
335 `cherry-picked <releasing.rst#pickntest>`__. Alternatively the release
336 manager will reply to the patch in question stating why the patch has
337 been rejected or would request a backport. The stable-release manager
338 may at times need to force-push changes to the stable branches, for
339 example, to drop a previously-picked patch that was later identified as
340 causing a regression). These force-pushes may cause changes to be lost
341 from the stable branch if developers push things directly. Consider
346 Sending backports for the stable branch
347 ---------------------------------------
349 By default merge conflicts are resolved by the stable-release manager.
350 The release maintainer should resolve trivial conflicts, but for complex
351 conflicts they should ask the original author to provide a backport or
352 de-nominate the patch.
354 For patches that either need to be nominated after they've landed in
355 master, or that are known ahead of time to not not apply cleanly to a
356 stable branch (such as due to a rename), using a gitlab MR is most
357 appropriate. The MR should be based on and target the
358 staging/year.quarter branch, not on the year.quarter branch, per the
359 stable branch policy. Assigning the MR to release maintainer for said
360 branch or mentioning them is helpful, but not required.
365 - ``git rebase -i ...`` is your friend. Don't be afraid to use it.
366 - Apply a fixup to commit FOO.
368 .. code-block:: console
371 git commit --fixup=FOO
372 git rebase -i --autosquash ...
374 - Test for build breakage between patches e.g last 8 commits.
376 .. code-block:: console
378 git rebase -i --exec="ninja -C build/" HEAD~8
380 - Sets the default mailing address for your repo.
382 .. code-block:: console
384 git config --local sendemail.to mesa-dev@lists.freedesktop.org
386 - Add version to subject line of patch series in this case for the last
387 8 commits before sending.
389 .. code-block:: console
391 git send-email --subject-prefix="PATCH v4" HEAD~8
392 git send-email -v4 @~8 # shorter version, inherited from git format-patch