docs/submittingpatches.html

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  11   <h1>The Mesa 3D Graphics Library</h1>
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  16
  17 <h1>Submitting patches</h1>
  18
  19
  20 <ul>
  21 <li><a href="#guidelines">Basic guidelines</a>
  22 <li><a href="#formatting">Patch formatting</a>
  23 <li><a href="#testing">Testing Patches</a>
  24 <li><a href="#mailing">Mailing Patches</a>
  25 <li><a href="#reviewing">Reviewing Patches</a>
  26 <li><a href="#nominations">Nominating a commit for a stable branch</a>
  27 <li><a href="#criteria">Criteria for accepting patches to the stable branch</a>
  28 <li><a href="#backports">Sending backports for the stable branch</a>
  29 <li><a href="#gittips">Git tips</a>
  30 </ul>
  31
  32 <h2 id="guidelines">Basic guidelines</h2>
  33
  34 <ul>
  35 <li>Patches should not mix code changes with code formatting changes (except,
  36 perhaps, in very trivial cases.)
  37 <li>Code patches should follow Mesa
  38 <a href="codingstyle.html" target="_parent">coding conventions</a>.
  39 <li>Whenever possible, patches should only effect individual Mesa/Gallium
  40 components.
  41 <li>Patches should never introduce build breaks and should be bisectable (see
  42 <code>git bisect</code>.)
  43 <li>Patches should be properly <a href="#formatting">formatted</a>.
  44 <li>Patches should be sufficiently <a href="#testing">tested</a> before submitting.
  45 <li>Patches should be submitted to <a href="#mailing">mesa-dev</a>
  46 for <a href="#reviewing">review</a> using <code>git send-email</code>.
  47
  48 </ul>
  49
  50 <h2 id="formatting">Patch formatting</h2>
  51
  52 <ul>
  53 <li>Lines should be limited to 75 characters or less so that git logs
  54 displayed in 80-column terminals avoid line wrapping.  Note that git
  55 log uses 4 spaces of indentation (4 + 75 &lt; 80).
  56 <li>The first line should be a short, concise summary of the change prefixed
  57 with a module name.  Examples:
  58 <pre>
  59     mesa: Add support for querying GL_VERTEX_ATTRIB_ARRAY_LONG
  60
  61     gallium: add PIPE_CAP_DEVICE_RESET_STATUS_QUERY
  62
  63     i965: Fix missing type in local variable declaration.
  64 </pre>
  65 <li>Subsequent patch comments should describe the change in more detail,
  66 if needed.  For example:
  67 <pre>
  68     i965: Remove end-of-thread SEND alignment code.
  69
  70     This was present in Eric's initial implementation of the compaction code
  71     for Sandybridge (commit 077d01b6). There is no documentation saying this
  72     is necessary, and removing it causes no regressions in piglit on any
  73     platform.
  74 </pre>
  75 <li>A "Signed-off-by:" line is not required, but not discouraged either.
  76 <li>If a patch addresses a bugzilla issue, that should be noted in the
  77 patch comment.  For example:
  78 <pre>
  79    Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=89689
  80 </pre>
  81 <li>If a patch addresses a issue introduced with earlier commit, that should be
  82 noted in the patch comment.  For example:
  83 <pre>
  84    Fixes: d7b3707c612 "util/disk_cache: use stat() to check if entry is a directory"
  85 </pre>
  86 <li>If there have been several revisions to a patch during the review
  87 process, they should be noted such as in this example:
  88 <pre>
  89     st/mesa: add ARB_texture_stencil8 support (v4)
  90
  91     if we support stencil texturing, enable texture_stencil8
  92     there is no requirement to support native S8 for this,
  93     the texture can be converted to x24s8 fine.
  94
  95     v2: fold fixes from Marek in:
  96        a) put S8 last in the list
  97        b) fix renderable to always test for d/s renderable
  98         fixup the texture case to use a stencil only format
  99         for picking the format for the texture view.
 100     v3: hit fallback for getteximage
 101     v4: put s8 back in front, it shouldn't get picked now (Ilia)
 102 </pre>
 103 <li>If someone tested your patch, document it with a line like this:
 104 <pre>
 105     Tested-by: Joe Hacker &lt;jhacker@foo.com&gt;
 106 </pre>
 107 <li>If the patch was reviewed (usually the case) or acked by someone,
 108 that should be documented with:
 109 <pre>
 110     Reviewed-by: Joe Hacker &lt;jhacker@foo.com&gt;
 111     Acked-by: Joe Hacker &lt;jhacker@foo.com&gt;
 112 </pre>
 113 <li>If sending later revision of a patch, add all the tags - ack, r-b,
 114 Cc: mesa-stable and/or other. This provides reviewers with quick feedback if the
 115 patch has already been reviewed.
 116 <li>In order for your patch to reach the prospective reviewer easier/faster,
 117 use the script scripts/get_reviewer.pl to get a list of individuals and include
 118 them in the CC list.
 119 <br>
 120 Please use common sense and do <strong>not</strong> blindly add everyone.
 121 <br>
 122 <pre>
 123     $ scripts/get_reviewer.pl --help # to get the help screen
 124     $ scripts/get_reviewer.pl -f src/egl/drivers/dri2/platform_android.c
 125     Rob Herring <robh@kernel.org> (reviewer:ANDROID EGL SUPPORT,added_lines:188/700=27%,removed_lines:58/283=20%)
 126     Tomasz Figa <tfiga@chromium.org> (reviewer:ANDROID EGL SUPPORT,authored:12/41=29%,added_lines:308/700=44%,removed_lines:115/283=41%)
 127     Emil Velikov <emil.l.velikov@gmail.com> (authored:13/41=32%,removed_lines:76/283=27%)
 128 </pre>
 129 </ul>
 130
 131
 132
 133 <h2 id="testing">Testing Patches</h2>
 134
 135 <p>
 136 It should go without saying that patches must be tested.  In general,
 137 do whatever testing is prudent.
 138 </p>
 139
 140 <p>
 141 You should always run the Mesa test suite before submitting patches.
 142 The test suite can be run using the 'make check' command. All tests
 143 must pass before patches will be accepted, this may mean you have
 144 to update the tests themselves.
 145 </p>
 146
 147 <p>
 148 Whenever possible and applicable, test the patch with
 149 <a href="https://piglit.freedesktop.org">Piglit</a> and/or
 150 <a href="https://android.googlesource.com/platform/external/deqp/">dEQP</a>
 151 to check for regressions.
 152 </p>
 153
 154 <p>
 155 As mentioned at the begining, patches should be bisectable.
 156 A good way to test this is to make use of the `git rebase` command,
 157 to run your tests on each commit. Assuming your branch is based off
 158 <code>origin/master</code>, you can run:
 159 <pre>
 160 $ git rebase --interactive --exec "make check" origin/master
 161 </pre>
 162 replacing <code>"make check"</code> with whatever other test you want to
 163 run.
 164 </p>
 165
 166
 167 <h2 id="mailing">Mailing Patches</h2>
 168
 169 <p>
 170 Patches should be sent to the mesa-dev mailing list for review:
 171 <a href="https://lists.freedesktop.org/mailman/listinfo/mesa-dev">
 172 mesa-dev@lists.freedesktop.org</a>.
 173 When submitting a patch make sure to use
 174 <a href="https://git-scm.com/docs/git-send-email">git send-email</a>
 175 rather than attaching patches to emails. Sending patches as
 176 attachments prevents people from being able to provide in-line review
 177 comments.
 178 </p>
 179
 180 <p>
 181 When submitting follow-up patches you can use --in-reply-to to make v2, v3,
 182 etc patches show up as replies to the originals. This usually works well
 183 when you're sending out updates to individual patches (as opposed to
 184 re-sending the whole series). Using --in-reply-to makes
 185 it harder for reviewers to accidentally review old patches.
 186 </p>
 187
 188 <p>
 189 When submitting follow-up patches you should also login to
 190 <a href="https://patchwork.freedesktop.org">patchwork</a> and change the
 191 state of your old patches to Superseded.
 192 </p>
 193
 194 <p>
 195 Some companies' mail server automatically append a legal disclaimer,
 196 usually containing something along the lines of "The information in this
 197 email is confidential" and "distribution is strictly prohibited".<br/>
 198 These legal notices prevent us from being able to accept your patch,
 199 rendering the whole process pointless. Please make sure these are
 200 disabled before sending your patches. (Note that you may need to contact
 201 your email administrator for this.)
 202 </p>
 203
 204 <h2 id="reviewing">Reviewing Patches</h2>
 205
 206 <p>
 207 When you've reviewed a patch on the mailing list, please be unambiguous
 208 about your review.  That is, state either
 209 </p>
 210 <pre>
 211     Reviewed-by: Joe Hacker &lt;jhacker@foo.com&gt;
 212 </pre>
 213 or
 214 <pre>
 215     Acked-by: Joe Hacker &lt;jhacker@foo.com&gt;
 216 </pre>
 217 <p>
 218 Rather than saying just "LGTM" or "Seems OK".
 219 </p>
 220
 221 <p>
 222 If small changes are suggested, it's OK to say something like:
 223 </p>
 224 <pre>
 225    With the above fixes, Reviewed-by: Joe Hacker &lt;jhacker@foo.com&gt;
 226 </pre>
 227 <p>
 228 which tells the patch author that the patch can be committed, as long
 229 as the issues are resolved first.
 230 </p>
 231
 232
 233 <h2 id="nominations">Nominating a commit for a stable branch</h2>
 234
 235 <p>
 236 There are three ways to nominate a patch for inclusion in the stable branch and
 237 release.
 238 </p>
 239 <ul>
 240 <li> By adding the Cc: mesa-stable@ tag as described below.
 241 <li> Sending the commit ID (as seen in master branch) to the mesa-stable@ mailing list.
 242 <li> Forwarding the patch from the mesa-dev@ mailing list.
 243 </li>
 244 </ul>
 245 <p>
 246 Note: resending patch identical to one on mesa-dev@ or one that differs only
 247 by the extra mesa-stable@ tag is <strong>not</strong> recommended.
 248 </p>
 249
 250
 251 <h3 id="thetag">The stable tag</h3>
 252
 253 <p>
 254 If you want a commit to be applied to a stable branch,
 255 you should add an appropriate note to the commit message.
 256 </p>
 257
 258 <p>
 259 Here are some examples of such a note:
 260 </p>
 261 <ul>
 262   <li>CC: &lt;mesa-stable@lists.freedesktop.org&gt;</li>
 263 </ul>
 264
 265 Simply adding the CC to the mesa-stable list address is adequate to nominate
 266 the commit for all the active stable branches. If the commit is not applicable
 267 for said branch the stable-release manager will reply stating so.
 268
 269 This "CC" syntax for patch nomination will cause patches to automatically be
 270 copied to the mesa-stable@ mailing list when you use "git send-email" to send
 271 patches to the mesa-dev@ mailing list. If you prefer using --suppress-cc that
 272 won't have any negative effect on the patch nomination.
 273
 274 <p>
 275 Note: by removing the tag [as the commit is pushed] the patch is
 276 <strong>explicitly</strong> rejected from inclusion in the stable branch(es).
 277 <br>
 278 Thus, drop the line <strong>only</strong> if you want to cancel the nomination.
 279 </p>
 280
 281 Alternatively, if one uses the "Fixes" tag as described in the "Patch formatting"
 282 section, it nominates a commit for all active stable branches that include the
 283 commit that is referred to.
 284
 285 <h2 id="criteria">Criteria for accepting patches to the stable branch</h2>
 286
 287 Mesa has a designated release manager for each stable branch, and the release
 288 manager is the only developer that should be pushing changes to these branches.
 289 Everyone else should nominate patches using the mechanism described above.
 290
 291 The following rules define which patches are accepted and which are not. The
 292 stable-release manager is also given broad discretion in rejecting patches
 293 that have been nominated.
 294
 295 <ul>
 296   <li>Patch must conform with the <a href="#guidelines">Basic guidelines</a></li>
 297
 298   <li>Patch must have landed in master first. In case where the original
 299   patch is too large and/or otherwise contradicts with the rules set within, a
 300   backport is appropriate.</li>
 301
 302   <li>It must not introduce a regression - be that build or runtime wise.
 303
 304   Note:  If the regression is due to faulty piglit/dEQP/CTS/other test the
 305   latter must be fixed first. A reference to the offending test(s) and
 306   respective fix(es) should be provided in the nominated patch.</li>
 307
 308   <li>Patch cannot be larger than 100 lines.</li>
 309
 310   <li>Patches that move code around with no functional change should be
 311   rejected.</li>
 312
 313   <li>Patch must be a bug fix and not a new feature.
 314
 315   Note: An exception to this rule, are hardware-enabling "features". For
 316   example, <a href="#backports">backports</a> of new code to support a
 317   newly-developed hardware product can be accepted if they can be reasonably
 318   determined not to have effects on other hardware.</li>
 319
 320   <li>Patch must be reviewed, For example, the commit message has Reviewed-by,
 321   Signed-off-by, or Tested-by tags from someone but the author.</li>
 322
 323   <li>Performance patches are considered only if they provide information
 324   about the hardware, program in question and observed improvement. Use numbers
 325   to represent your measurements.</li>
 326 </ul>
 327
 328 If the patch complies with the rules it will be
 329 <a href="releasing.html#pickntest">cherry-picked</a>. Alternatively the release
 330 manager will reply to the patch in question stating why the patch has been
 331 rejected or would request a backport.
 332
 333 A summary of all the picked/rejected patches will be presented in the
 334 <a href="releasing.html#prerelease">pre-release</a> announcement.
 335
 336 The stable-release manager may at times need to force-push changes to the
 337 stable branches, for example, to drop a previously-picked patch that was later
 338 identified as causing a regression). These force-pushes may cause changes to
 339 be lost from the stable branch if developers push things directly. Consider
 340 yourself warned.
 341
 342 <h2 id="backports">Sending backports for the stable branch</h2>
 343 By default merge conflicts are resolved by the stable-release manager. In which
 344 case he/she should provide a comment about the changes required, alongside the
 345 <code>Conflicts</code> section. Summary of which will be provided in the
 346 <a href="releasing.html#prerelease">pre-release</a> announcement.
 347 <br>
 348 Developers are interested in sending backports are recommended to use either a
 349 <code>[BACKPORT #branch]</code> subject prefix or provides similar information
 350 within the commit summary.
 351
 352 <h2 id="gittips">Git tips</h2>
 353
 354 <ul>
 355 <li><code>git rebase -i ...</code> is your friend. Don't be afraid to use it.
 356 <li>Apply a fixup to commit FOO.
 357 <pre>
 358     git add ...
 359     git commit --fixup=FOO
 360     git rebase -i --autosquash ...
 361 </pre>
 362 <li>Test for build breakage between patches e.g last 8 commits.
 363 <pre>
 364     git rebase -i --exec="make -j4" HEAD~8
 365 </pre>
 366 <li>Sets the default mailing address for your repo.
 367 <pre>
 368     git config --local sendemail.to mesa-dev@lists.freedesktop.org
 369 </pre>
 370 <li> Add version to subject line of patch series in this case for the last 8
 371 commits before sending.
 372 <pre>
 373     git send-email --subject-prefix="PATCH v4" HEAD~8
 374     git send-email -v4 @~8 # shorter version, inherited from git format-patch
 375 </pre>
 376 <li> Configure git to use the get_reviewer.pl script interactively. Thus you
 377 can avoid adding the world to the CC list.
 378 <pre>
 379     git config sendemail.cccmd "./scripts/get_reviewer.pl -i"
 380 </pre>
 381 </ul>
 382
 383
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