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
 155 <h2 id="mailing">Mailing Patches</h2>
 156
 157 <p>
 158 Patches should be sent to the mesa-dev mailing list for review:
 159 <a href="https://lists.freedesktop.org/mailman/listinfo/mesa-dev">
 160 mesa-dev@lists.freedesktop.org</a>.
 161 When submitting a patch make sure to use
 162 <a href="https://git-scm.com/docs/git-send-email">git send-email</a>
 163 rather than attaching patches to emails. Sending patches as
 164 attachments prevents people from being able to provide in-line review
 165 comments.
 166 </p>
 167
 168 <p>
 169 When submitting follow-up patches you can use --in-reply-to to make v2, v3,
 170 etc patches show up as replies to the originals. This usually works well
 171 when you're sending out updates to individual patches (as opposed to
 172 re-sending the whole series). Using --in-reply-to makes
 173 it harder for reviewers to accidentally review old patches.
 174 </p>
 175
 176 <p>
 177 When submitting follow-up patches you should also login to
 178 <a href="https://patchwork.freedesktop.org">patchwork</a> and change the
 179 state of your old patches to Superseded.
 180 </p>
 181
 182 <p>
 183 Some companies' mail server automatically append a legal disclaimer,
 184 usually containing something along the lines of "The information in this
 185 email is confidential" and "distribution is strictly prohibited".<br/>
 186 These legal notices prevent us from being able to accept your patch,
 187 rendering the whole process pointless. Please make sure these are
 188 disabled before sending your patches. (Note that you may need to contact
 189 your email administrator for this.)
 190 </p>
 191
 192 <h2 id="reviewing">Reviewing Patches</h2>
 193
 194 <p>
 195 When you've reviewed a patch on the mailing list, please be unambiguous
 196 about your review.  That is, state either
 197 </p>
 198 <pre>
 199     Reviewed-by: Joe Hacker &lt;jhacker@foo.com&gt;
 200 </pre>
 201 or
 202 <pre>
 203     Acked-by: Joe Hacker &lt;jhacker@foo.com&gt;
 204 </pre>
 205 <p>
 206 Rather than saying just "LGTM" or "Seems OK".
 207 </p>
 208
 209 <p>
 210 If small changes are suggested, it's OK to say something like:
 211 </p>
 212 <pre>
 213    With the above fixes, Reviewed-by: Joe Hacker &lt;jhacker@foo.com&gt;
 214 </pre>
 215 <p>
 216 which tells the patch author that the patch can be committed, as long
 217 as the issues are resolved first.
 218 </p>
 219
 220
 221 <h2 id="nominations">Nominating a commit for a stable branch</h2>
 222
 223 <p>
 224 There are three ways to nominate a patch for inclusion in the stable branch and
 225 release.
 226 </p>
 227 <ul>
 228 <li> By adding the Cc: mesa-stable@ tag as described below.
 229 <li> Sending the commit ID (as seen in master branch) to the mesa-stable@ mailing list.
 230 <li> Forwarding the patch from the mesa-dev@ mailing list.
 231 </li>
 232 </ul>
 233 <p>
 234 Note: resending patch identical to one on mesa-dev@ or one that differs only
 235 by the extra mesa-stable@ tag is <strong>not</strong> recommended.
 236 </p>
 237
 238
 239 <h3 id="thetag">The stable tag</h3>
 240
 241 <p>
 242 If you want a commit to be applied to a stable branch,
 243 you should add an appropriate note to the commit message.
 244 </p>
 245
 246 <p>
 247 Here are some examples of such a note:
 248 </p>
 249 <ul>
 250   <li>CC: &lt;mesa-stable@lists.freedesktop.org&gt;</li>
 251 </ul>
 252
 253 Simply adding the CC to the mesa-stable list address is adequate to nominate
 254 the commit for all the active stable branches. If the commit is not applicable
 255 for said branch the stable-release manager will reply stating so.
 256
 257 This "CC" syntax for patch nomination will cause patches to automatically be
 258 copied to the mesa-stable@ mailing list when you use "git send-email" to send
 259 patches to the mesa-dev@ mailing list. If you prefer using --suppress-cc that
 260 won't have any negative effect on the patch nomination.
 261
 262 <p>
 263 Note: by removing the tag [as the commit is pushed] the patch is
 264 <strong>explicitly</strong> rejected from inclusion in the stable branch(es).
 265 <br>
 266 Thus, drop the line <strong>only</strong> if you want to cancel the nomination.
 267 </p>
 268
 269 Alternatively, if one uses the "Fixes" tag as described in the "Patch formatting"
 270 section, it nominates a commit for all active stable branches that include the
 271 commit that is referred to.
 272
 273 <h2 id="criteria">Criteria for accepting patches to the stable branch</h2>
 274
 275 Mesa has a designated release manager for each stable branch, and the release
 276 manager is the only developer that should be pushing changes to these branches.
 277 Everyone else should nominate patches using the mechanism described above.
 278
 279 The following rules define which patches are accepted and which are not. The
 280 stable-release manager is also given broad discretion in rejecting patches
 281 that have been nominated.
 282
 283 <ul>
 284   <li>Patch must conform with the <a href="#guidelines">Basic guidelines</a></li>
 285
 286   <li>Patch must have landed in master first. In case where the original
 287   patch is too large and/or otherwise contradicts with the rules set within, a
 288   backport is appropriate.</li>
 289
 290   <li>It must not introduce a regression - be that build or runtime wise.
 291
 292   Note:  If the regression is due to faulty piglit/dEQP/CTS/other test the
 293   latter must be fixed first. A reference to the offending test(s) and
 294   respective fix(es) should be provided in the nominated patch.</li>
 295
 296   <li>Patch cannot be larger than 100 lines.</li>
 297
 298   <li>Patches that move code around with no functional change should be
 299   rejected.</li>
 300
 301   <li>Patch must be a bug fix and not a new feature.
 302
 303   Note: An exception to this rule, are hardware-enabling "features". For
 304   example, <a href="#backports">backports</a> of new code to support a
 305   newly-developed hardware product can be accepted if they can be reasonably
 306   determined not to have effects on other hardware.</li>
 307
 308   <li>Patch must be reviewed, For example, the commit message has Reviewed-by,
 309   Signed-off-by, or Tested-by tags from someone but the author.</li>
 310
 311   <li>Performance patches are considered only if they provide information
 312   about the hardware, program in question and observed improvement. Use numbers
 313   to represent your measurements.</li>
 314 </ul>
 315
 316 If the patch complies with the rules it will be
 317 <a href="releasing.html#pickntest">cherry-picked</a>. Alternatively the release
 318 manager will reply to the patch in question stating why the patch has been
 319 rejected or would request a backport.
 320
 321 A summary of all the picked/rejected patches will be presented in the
 322 <a href="releasing.html#prerelease">pre-release</a> announcement.
 323
 324 The stable-release manager may at times need to force-push changes to the
 325 stable branches, for example, to drop a previously-picked patch that was later
 326 identified as causing a regression). These force-pushes may cause changes to
 327 be lost from the stable branch if developers push things directly. Consider
 328 yourself warned.
 329
 330 <h2 id="backports">Sending backports for the stable branch</h2>
 331 By default merge conflicts are resolved by the stable-release manager. In which
 332 case he/she should provide a comment about the changes required, alongside the
 333 <code>Conflicts</code> section. Summary of which will be provided in the
 334 <a href="releasing.html#prerelease">pre-release</a> announcement.
 335 <br>
 336 Developers are interested in sending backports are recommended to use either a
 337 <code>[BACKPORT #branch]</code> subject prefix or provides similar information
 338 within the commit summary.
 339
 340 <h2 id="gittips">Git tips</h2>
 341
 342 <ul>
 343 <li><code>git rebase -i ...</code> is your friend. Don't be afraid to use it.
 344 <li>Apply a fixup to commit FOO.
 345 <pre>
 346     git add ...
 347     git commit --fixup=FOO
 348     git rebase -i --autosquash ...
 349 </pre>
 350 <li>Test for build breakage between patches e.g last 8 commits.
 351 <pre>
 352     git rebase -i --exec="make -j4" HEAD~8
 353 </pre>
 354 <li>Sets the default mailing address for your repo.
 355 <pre>
 356     git config --local sendemail.to mesa-dev@lists.freedesktop.org
 357 </pre>
 358 <li> Add version to subject line of patch series in this case for the last 8
 359 commits before sending.
 360 <pre>
 361     git send-email --subject-prefix="PATCH v4" HEAD~8
 362     git send-email -v4 @~8 # shorter version, inherited from git format-patch
 363 </pre>
 364 <li> Configure git to use the get_reviewer.pl script interactively. Thus you
 365 can avoid adding the world to the CC list.
 366 <pre>
 367     git config sendemail.cccmd "./scripts/get_reviewer.pl -i"
 368 </pre>
 369 </ul>
 370
 371
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