docs/submittingpatches.html

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  11   <h1>The Mesa 3D Graphics Library</h1>
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  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="#gittips">Git tips</a>
  29 </ul>
  30
  31 <h2 id="guidelines">Basic guidelines</h2>
  32
  33 <ul>
  34 <li>Patches should not mix code changes with code formatting changes (except,
  35 perhaps, in very trivial cases.)
  36 <li>Code patches should follow Mesa
  37 <a href="codingstyle.html" target="_parent">coding conventions</a>.
  38 <li>Whenever possible, patches should only effect individual Mesa/Gallium
  39 components.
  40 <li>Patches should never introduce build breaks and should be bisectable (see
  41 <code>git bisect</code>.)
  42 <li>Patches should be properly <a href="#formatting">formatted</a>.
  43 <li>Patches should be sufficiently <a href="#testing">tested</a> before submitting.
  44 <li>Patches should be submitted to <a href="#mailing">mesa-dev</a>
  45 for <a href="#reviewing">review</a> using <code>git send-email</code>.
  46
  47 </ul>
  48
  49 <h2 id="formatting">Patch formatting</h2>
  50
  51 <ul>
  52 <li>Lines should be limited to 75 characters or less so that git logs
  53 displayed in 80-column terminals avoid line wrapping.  Note that git
  54 log uses 4 spaces of indentation (4 + 75 &lt; 80).
  55 <li>The first line should be a short, concise summary of the change prefixed
  56 with a module name.  Examples:
  57 <pre>
  58     mesa: Add support for querying GL_VERTEX_ATTRIB_ARRAY_LONG
  59
  60     gallium: add PIPE_CAP_DEVICE_RESET_STATUS_QUERY
  61
  62     i965: Fix missing type in local variable declaration.
  63 </pre>
  64 <li>Subsequent patch comments should describe the change in more detail,
  65 if needed.  For example:
  66 <pre>
  67     i965: Remove end-of-thread SEND alignment code.
  68
  69     This was present in Eric's initial implementation of the compaction code
  70     for Sandybridge (commit 077d01b6). There is no documentation saying this
  71     is necessary, and removing it causes no regressions in piglit on any
  72     platform.
  73 </pre>
  74 <li>A "Signed-off-by:" line is not required, but not discouraged either.
  75 <li>If a patch addresses a bugzilla issue, that should be noted in the
  76 patch comment.  For example:
  77 <pre>
  78    Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=89689
  79 </pre>
  80 <li>If there have been several revisions to a patch during the review
  81 process, they should be noted such as in this example:
  82 <pre>
  83     st/mesa: add ARB_texture_stencil8 support (v4)
  84
  85     if we support stencil texturing, enable texture_stencil8
  86     there is no requirement to support native S8 for this,
  87     the texture can be converted to x24s8 fine.
  88
  89     v2: fold fixes from Marek in:
  90        a) put S8 last in the list
  91        b) fix renderable to always test for d/s renderable
  92         fixup the texture case to use a stencil only format
  93         for picking the format for the texture view.
  94     v3: hit fallback for getteximage
  95     v4: put s8 back in front, it shouldn't get picked now (Ilia)
  96 </pre>
  97 <li>If someone tested your patch, document it with a line like this:
  98 <pre>
  99     Tested-by: Joe Hacker &lt;jhacker@foo.com&gt;
 100 </pre>
 101 <li>If the patch was reviewed (usually the case) or acked by someone,
 102 that should be documented with:
 103 <pre>
 104     Reviewed-by: Joe Hacker &lt;jhacker@foo.com&gt;
 105     Acked-by: Joe Hacker &lt;jhacker@foo.com&gt;
 106 </pre>
 107 <li>If sending later revision of a patch, add all the tags - ack, r-b,
 108 Cc: mesa-stable and/or other. This provides reviewers with quick feedback if the
 109 patch has already been reviewed.
 110 <li>In order for your patch to reach the prospective reviewer easier/faster,
 111 use the script scripts/get_reviewer.pl to get a list of individuals and include
 112 them in the CC list.
 113 <br>
 114 Please use common sense and do <strong>not</strong> blindly add everyone.
 115 <br>
 116 <pre>
 117     $ scripts/get_reviewer.pl --help # to get the the help screen
 118     $ scripts/get_reviewer.pl -f src/egl/drivers/dri2/platform_android.c
 119     Rob Herring <robh@kernel.org> (reviewer:ANDROID EGL SUPPORT,added_lines:188/700=27%,removed_lines:58/283=20%)
 120     Tomasz Figa <tfiga@chromium.org> (reviewer:ANDROID EGL SUPPORT,authored:12/41=29%,added_lines:308/700=44%,removed_lines:115/283=41%)
 121     Emil Velikov <emil.l.velikov@gmail.com> (authored:13/41=32%,removed_lines:76/283=27%)
 122 </pre>
 123 </ul>
 124
 125
 126
 127 <h2 id="testing">Testing Patches</h2>
 128
 129 <p>
 130 It should go without saying that patches must be tested.  In general,
 131 do whatever testing is prudent.
 132 </p>
 133
 134 <p>
 135 You should always run the Mesa test suite before submitting patches.
 136 The test suite can be run using the 'make check' command. All tests
 137 must pass before patches will be accepted, this may mean you have
 138 to update the tests themselves.
 139 </p>
 140
 141 <p>
 142 Whenever possible and applicable, test the patch with
 143 <a href="https://piglit.freedesktop.org">Piglit</a> and/or
 144 <a href="https://android.googlesource.com/platform/external/deqp/">dEQP</a>
 145 to check for regressions.
 146 </p>
 147
 148
 149 <h2 id="mailing">Mailing Patches</h2>
 150
 151 <p>
 152 Patches should be sent to the mesa-dev mailing list for review:
 153 <a href="https://lists.freedesktop.org/mailman/listinfo/mesa-dev">
 154 mesa-dev@lists.freedesktop.org</a>.
 155 When submitting a patch make sure to use
 156 <a href="https://git-scm.com/docs/git-send-email">git send-email</a>
 157 rather than attaching patches to emails. Sending patches as
 158 attachments prevents people from being able to provide in-line review
 159 comments.
 160 </p>
 161
 162 <p>
 163 When submitting follow-up patches you can use --in-reply-to to make v2, v3,
 164 etc patches show up as replies to the originals. This usually works well
 165 when you're sending out updates to individual patches (as opposed to
 166 re-sending the whole series). Using --in-reply-to makes
 167 it harder for reviewers to accidentally review old patches.
 168 </p>
 169
 170 <p>
 171 When submitting follow-up patches you should also login to
 172 <a href="https://patchwork.freedesktop.org">patchwork</a> and change the
 173 state of your old patches to Superseded.
 174 </p>
 175
 176 <h2 id="reviewing">Reviewing Patches</h2>
 177
 178 <p>
 179 When you've reviewed a patch on the mailing list, please be unambiguous
 180 about your review.  That is, state either
 181 </p>
 182 <pre>
 183     Reviewed-by: Joe Hacker &lt;jhacker@foo.com&gt;
 184 </pre>
 185 or
 186 <pre>
 187     Acked-by: Joe Hacker &lt;jhacker@foo.com&gt;
 188 </pre>
 189 <p>
 190 Rather than saying just "LGTM" or "Seems OK".
 191 </p>
 192
 193 <p>
 194 If small changes are suggested, it's OK to say something like:
 195 </p>
 196 <pre>
 197    With the above fixes, Reviewed-by: Joe Hacker &lt;jhacker@foo.com&gt;
 198 </pre>
 199 <p>
 200 which tells the patch author that the patch can be committed, as long
 201 as the issues are resolved first.
 202 </p>
 203
 204
 205 <h2 id="nominations">Nominating a commit for a stable branch</h2>
 206
 207 <p>
 208 There are three ways to nominate a patch for inclusion in the stable branch and
 209 release.
 210 </p>
 211 <ul>
 212 <li> By adding the Cc: mesa-stable@ tag as described below.
 213 <li> Sending the commit ID (as seen in master branch) to the mesa-stable@ mailing list.
 214 <li> Forwarding the patch from the mesa-dev@ mailing list.
 215 </li>
 216 </ul>
 217 <p>
 218 Note: resending patch identical to one on mesa-dev@ or one that differs only
 219 by the extra mesa-stable@ tag is <strong>not</strong> recommended.
 220 </p>
 221
 222
 223 <h3 id="thetag">The stable tag</h3>
 224
 225 <p>
 226 If you want a commit to be applied to a stable branch,
 227 you should add an appropriate note to the commit message.
 228 </p>
 229
 230 <p>
 231 Here are some examples of such a note:
 232 </p>
 233 <ul>
 234   <li>CC: &lt;mesa-stable@lists.freedesktop.org&gt;</li>
 235   <li>CC: "9.2 10.0" &lt;mesa-stable@lists.freedesktop.org&gt;</li>
 236   <li>CC: "10.0" &lt;mesa-stable@lists.freedesktop.org&gt;</li>
 237 </ul>
 238
 239 Simply adding the CC to the mesa-stable list address is adequate to nominate
 240 the commit for the most-recently-created stable branch. It is only necessary
 241 to specify a specific branch name, (such as "9.2 10.0" or "10.0" in the
 242 examples above), if you want to nominate the commit for an older stable
 243 branch. And, as in these examples, you can nominate the commit for the older
 244 branch in addition to the more recent branch, or nominate the commit
 245 exclusively for the older branch.
 246
 247 This "CC" syntax for patch nomination will cause patches to automatically be
 248 copied to the mesa-stable@ mailing list when you use "git send-email" to send
 249 patches to the mesa-dev@ mailing list. If you prefer using --suppress-cc that
 250 won't have any negative effect on the patch nomination.
 251
 252 <p>
 253 Note: by removing the tag [as the commit is pushed] the patch is
 254 <strong>explicitly</strong> rejected from inclusion in the stable branch(es).
 255 <br>
 256 Thus, drop the line <strong>only</strong> if you want to cancel the nomination.
 257 </p>
 258
 259 <h2 id="criteria">Criteria for accepting patches to the stable branch</h2>
 260
 261 Mesa has a designated release manager for each stable branch, and the release
 262 manager is the only developer that should be pushing changes to these branches.
 263 Everyone else should nominate patches using the mechanism described above.
 264
 265 The following rules define which patches are accepted and which are not. The
 266 stable-release manager is also given broad discretion in rejecting patches
 267 that have been nominated.
 268
 269 <ul>
 270   <li>Patch must conform with the <a href="#guidelines">Basic guidelines</a></li>
 271
 272   <li>Patch must have landed in master first. In case where the original
 273   patch is too large and/or otherwise contradicts with the rules set within, a
 274   backport is appropriate.</li>
 275
 276   <li>It must not introduce a regression - be that build or runtime wise.
 277
 278   Note:  If the regression is due to faulty piglit/dEQP/CTS/other test the
 279   latter must be fixed first. A reference to the offending test(s) and
 280   respective fix(es) should be provided in the nominated patch.</li>
 281
 282   <li>Patch cannot be larger than 100 lines.</li>
 283
 284   <li>Patches that move code around with no functional change should be
 285   rejected.</li>
 286
 287   <li>Patch must be a bug fix and not a new feature.
 288
 289   Note: An exception to this rule, are hardware-enabling "features". For
 290   example, backports of new code to support a newly-developed hardware product
 291   can be accepted if they can be reasonably determined not to have effects on
 292   other hardware.</li>
 293
 294   <li>Patch must be reviewed, For example, the commit message has Reviewed-by,
 295   Signed-off-by, or Tested-by tags from someone but the author.</li>
 296
 297   <li>Performance patches are considered only if they provide information
 298   about the hardware, program in question and observed improvement. Use numbers
 299   to represent your measurements.</li>
 300 </ul>
 301
 302 If the patch complies with the rules it will be
 303 <a href="releasing.html#pickntest">cherry-picked</a>. Alternatively the release
 304 manager will reply to the patch in question stating why the patch has been
 305 rejected or would request a backport.
 306
 307 A summary of all the picked/rejected patches will be presented in the
 308 <a href="releasing.html#prerelease">pre-release</a> announcement.
 309
 310 The stable-release manager may at times need to force-push changes to the
 311 stable branches, for example, to drop a previously-picked patch that was later
 312 identified as causing a regression). These force-pushes may cause changes to
 313 be lost from the stable branch if developers push things directly. Consider
 314 yourself warned.
 315
 316 <h2 id="gittips">Git tips</h2>
 317
 318 <ul>
 319 <li><code>git rebase -i ...</code> is your friend. Don't be afraid to use it.
 320 <li>Apply a fixup to commit FOO.
 321 <pre>
 322     git add ...
 323     git commit --fixup=FOO
 324     git rebase -i --autosquash ...
 325 </pre>
 326 <li>Test for build breakage between patches e.g last 8 commits.
 327 <pre>
 328     git rebase -i --exec="make -j4" HEAD~8
 329 </pre>
 330 <li>Sets the default mailing address for your repo.
 331 <pre>
 332     git config --local sendemail.to mesa-dev@lists.freedesktop.org
 333 </pre>
 334 <li> Add version to subject line of patch series in this case for the last 8
 335 commits before sending.
 336 <pre>
 337     git send-email --subject-prefix="PATCH v4" HEAD~8
 338     git send-email -v4 @~8 # shorter version, inherited from git format-patch
 339 </pre>
 340 <li> Configure git to use the get_reviewer.pl script interactively. Thus you
 341 can avoid adding the world to the CC list.
 342 <pre>
 343     git config sendemail.cccmd "./scripts/get_reviewer.pl -i"
 344 </pre>
 345 </ul>
 346
 347
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