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549 lines
16 KiB
HTML
549 lines
16 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
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<html lang="en">
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<head>
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<meta http-equiv="content-type" content="text/html; charset=utf-8">
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<title>Development Notes</title>
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<link rel="stylesheet" type="text/css" href="mesa.css">
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</head>
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<body>
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<div class="header">
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<h1>The Mesa 3D Graphics Library</h1>
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</div>
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<iframe src="contents.html"></iframe>
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<div class="content">
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<h1>Development Notes</h1>
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<h2>Adding Extensions</h2>
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<p>
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To add a new GL extension to Mesa you have to do at least the following.
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<ul>
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<li>
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If glext.h doesn't define the extension, edit include/GL/gl.h and add
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code like this:
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<pre>
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#ifndef GL_EXT_the_extension_name
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#define GL_EXT_the_extension_name 1
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/* declare the new enum tokens */
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/* prototype the new functions */
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/* TYPEDEFS for the new functions */
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#endif
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</pre>
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</li>
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<li>
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In the src/mapi/glapi/gen/ directory, add the new extension functions and
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enums to the gl_API.xml file.
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Then, a bunch of source files must be regenerated by executing the
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corresponding Python scripts.
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</li>
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<li>
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Add a new entry to the <code>gl_extensions</code> struct in mtypes.h
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</li>
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<li>
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Update the <code>extensions.c</code> file.
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</li>
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<li>
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From this point, the best way to proceed is to find another extension,
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similar to the new one, that's already implemented in Mesa and use it
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as an example.
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</li>
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<li>
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If the new extension adds new GL state, the functions in get.c, enable.c
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and attrib.c will most likely require new code.
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</li>
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<li>
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The dispatch tests check_table.cpp and dispatch_sanity.cpp
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should be updated with details about the new extensions functions. These
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tests are run using 'make check'
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</li>
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</ul>
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<h2>Coding Style</h2>
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<p>
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Mesa's code style has changed over the years. Here's the latest.
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</p>
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<p>
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Comment your code! It's extremely important that open-source code be
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well documented. Also, strive to write clean, easily understandable code.
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</p>
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<p>
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3-space indentation
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</p>
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<p>
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If you use tabs, set them to 8 columns
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</p>
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<p>
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Line width: the preferred width to fill comments and code in Mesa is 78
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columns. Exceptions are sometimes made for clarity (e.g. tabular data is
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sometimes filled to a much larger width so that extraneous carriage returns
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don't obscure the table).
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</p>
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<p>
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Brace example:
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</p>
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<pre>
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if (condition) {
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foo;
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}
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else {
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bar;
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}
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switch (condition) {
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case 0:
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foo();
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break;
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case 1: {
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...
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break;
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}
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default:
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...
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break;
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}
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</pre>
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<p>
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Here's the GNU indent command which will best approximate my preferred style:
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(Note that it won't format switch statements in the preferred way)
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</p>
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<pre>
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indent -br -i3 -npcs --no-tabs infile.c -o outfile.c
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</pre>
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<p>
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Local variable name example: localVarName (no underscores)
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</p>
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<p>
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Constants and macros are ALL_UPPERCASE, with _ between words
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</p>
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<p>
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Global variables are not allowed.
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</p>
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<p>
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Function name examples:
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</p>
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<pre>
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glFooBar() - a public GL entry point (in glapi_dispatch.c)
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_mesa_FooBar() - the internal immediate mode function
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save_FooBar() - retained mode (display list) function in dlist.c
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foo_bar() - a static (private) function
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_mesa_foo_bar() - an internal non-static Mesa function
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</pre>
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<p>
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Places that are not directly visible to the GL API should prefer the use
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of <tt>bool</tt>, <tt>true</tt>, and
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<tt>false</tt> over <tt>GLboolean</tt>, <tt>GL_TRUE</tt>, and
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<tt>GL_FALSE</tt>. In C code, this may mean that
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<tt>#include <stdbool.h></tt> needs to be added. The
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<tt>try_emit_</tt>* methods in src/mesa/program/ir_to_mesa.cpp and
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src/mesa/state_tracker/st_glsl_to_tgsi.cpp can serve as examples.
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</p>
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<h2>Submitting patches</h2>
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<p>
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You should always run the Mesa Testsuite before submitting patches.
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The Testsuite can be run using the 'make check' command. All tests
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must pass before patches will be accepted, this may mean you have
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to update the tests themselves.
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</p>
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<p>
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Patches should be sent to the Mesa mailing list for review.
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When submitting a patch make sure to use git send-email rather than attaching
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patches to emails. Sending patches as attachments prevents people from being
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able to provide in-line review comments.
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</p>
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<p>
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When submitting follow-up patches you can use --in-reply-to to make v2, v3,
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etc patches show up as replies to the originals. This usually works well
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when you're sending out updates to individual patches (as opposed to
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re-sending the whole series). Using --in-reply-to makes
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it harder for reviewers to accidentally review old patches.
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</p>
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<h2>Marking a commit as a candidate for a stable branch</h2>
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<p>
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If you want a commit to be applied to a stable branch,
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you should add an appropriate note to the commit message.
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</p>
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<p>
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Here are some examples of such a note:
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</p>
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<ul>
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<li>CC: <mesa-stable@lists.freedesktop.org></li>
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<li>CC: "9.2 10.0" <mesa-stable@lists.freedesktop.org></li>
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<li>CC: "10.0" <mesa-stable@lists.freedesktop.org></li>
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</ul>
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Simply adding the CC to the mesa-stable list address is adequate to nominate
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the commit for the most-recently-created stable branch. It is only necessary
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to specify a specific branch name, (such as "9.2 10.0" or "10.0" in the
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examples above), if you want to nominate the commit for an older stable
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branch. And, as in these examples, you can nominate the commit for the older
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branch in addition to the more recent branch, or nominate the commit
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exclusively for the older branch.
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This "CC" syntax for patch nomination will cause patches to automatically be
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copied to the mesa-stable@ mailing list when you use "git send-email" to send
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patches to the mesa-dev@ mailing list. Also, if you realize that a commit
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should be nominated for the stable branch after it has already been committed,
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you can send a note directly to the mesa-stable@lists.freedesktop.org where
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the Mesa stable-branch maintainers will receive it. Be sure to mention the
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commit ID of the commit of interest (as it appears in the mesa master branch).
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The latest set of patches that have been nominated, accepted, or rejected for
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the upcoming stable release can always be seen on the
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<a href="http://cworth.org/~cworth/mesa-stable-queue/">Mesa Stable Queue</a>
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page.
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<h2>Criteria for accepting patches to the stable branch</h2>
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Mesa has a designated release manager for each stable branch, and the release
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manager is the only developer that should be pushing changes to these
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branches. Everyone else should simply nominate patches using the mechanism
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described above.
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The stable-release manager will work with the list of nominated patches, and
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for each patch that meets the crtieria below will cherry-pick the patch with:
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<code>git cherry-pick -x <commit></code>. The <code>-x</code> option is
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important so that the picked patch references the comit ID of the original
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patch.
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The stable-release manager may at times need to force-push changes to the
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stable branches, for example, to drop a previously-picked patch that was later
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identified as causing a regression). These force-pushes may cause changes to
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be lost from the stable branch if developers push things directly. Consider
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yourself warned.
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The stable-release manager is also given broad discretion in rejecting patches
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that have been nominated for the stable branch. The most basic rule is that
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the stable branch is for bug fixes only, (no new features, no
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regressions). Here is a non-exhaustive list of some reasons that a patch may
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be rejected:
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<ul>
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<li>Patch introduces a regression. Any reported build breakage or other
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regression caused by a particular patch, (game no longer work, piglit test
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changes from PASS to FAIL), is justification for rejecting a patch.</li>
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<li>Patch is too large, (say, larger than 100 lines)</li>
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<li>Patch is not a fix. For example, a commit that moves code around with no
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functional change should be rejected.</li>
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<li>Patch fix is not clearly described. For example, a commit message
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of only a single line, no description of the bug, no mention of bugzilla,
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etc.</li>
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<li>Patch has not obviously been reviewed, For example, the commit message
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has no Reviewed-by, Signed-off-by, nor Tested-by tags from anyone but the
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author.</li>
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<li>Patch has not already been merged to the master branch. As a rule, bug
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fixes should never be applied first to a stable branch. Patches should land
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first on the master branch and then be cherry-picked to a stable
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branch. (This is to avoid future releases causing regressions if the patch
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is not also applied to master.) The only things that might look like
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exceptions would be backports of patches from master that happen to look
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significantly different.</li>
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<li>Patch depends on too many other patches. Ideally, all stable-branch
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patches should be self-contained. It sometimes occurs that a single, logical
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bug-fix occurs as two separate patches on master, (such as an original
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patch, then a subsequent fix-up to that patch). In such a case, these two
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patches should be squashed into a single, self-contained patch for the
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stable branch. (Of course, if the squashing makes the patch too large, then
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that could be a reason to reject the patch.)</li>
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<li>Patch includes new feature development, not bug fixes. New OpenGL
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features, extensions, etc. should be applied to Mesa master and included in
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the next major release. Stable releases are intended only for bug fixes.
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Note: As an exception to this rule, the stable-release manager may accept
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hardware-enabling "features". For example, backports of new code to support
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a newly-developed hardware product can be accepted if they can be reasonably
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determined to not have effects on other hardware.</li>
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<li>Patch is a performance optimization. As a rule, performance patches are
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not candidates for the stable branch. The only exception might be a case
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where an application's performance was recently severely impacted so as to
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become unusable. The fix for this performance regression could then be
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considered for a stable branch. The optimization must also be
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non-controversial and the patches still need to meet the other criteria of
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being simple and self-contained</li>
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<li>Patch introduces a new failure mode (such as an assert). While the new
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assert might technically be correct, for example to make Mesa more
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conformant, this is not the kind of "bug fix" we want in a stable
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release. The potential problem here is that an OpenGL program that was
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previously working, (even if technically non-compliant with the
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specification), could stop working after this patch. So that would be a
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regression that is unaacceptable for the stable branch.</li>
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</ul>
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<h2>Making a New Mesa Release</h2>
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<p>
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These are the instructions for making a new Mesa release.
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</p>
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<h3>Get latest source files</h3>
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<p>
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Use git to get the latest Mesa files from the git repository, from whatever
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branch is relevant. This document uses the convention X.Y.Z for the release
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being created, which should be created from a branch named X.Y.
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</p>
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<h3>Perform basic testing</h3>
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<p>
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The release manager should, at the very least, test the code by compiling it,
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installing it, and running the latest piglit to ensure that no piglit tests
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have regressed since the previous release.
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</p>
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<p>
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The release manager should do this testing with at least one hardware driver,
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(say, whatever is contained in the local development machine), as well as on
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both Gallium and non-Gallium software drivers. The software testing can be
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performed by running piglit with the following environment-variable set:
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</p>
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<pre>
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LIBGL_ALWAYS_SOFTWARE=1
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</pre>
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And Gallium vs. non-Gallium software drivers can be obtained by using the
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following configure flags on separate builds:
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<pre>
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--with-dri-drivers=swrast
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--with-gallium-drivers=swrast
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</pre>
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<p>
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Note: If both options are given in one build, both swrast_dri.so drivers will
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be compiled, but only one will be installed. The following command can be used
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to ensure the correct driver is being tested:
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</p>
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<pre>
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LIBGL_ALWAYS_SOFTWARE=1 glxinfo | grep "renderer string"
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</pre>
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If any regressions are found in this testing with piglit, stop here, and do
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not perform a release until regressions are fixed.
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<h3>Update version in file VERSION</h3>
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<p>
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Increment the version contained in the file VERSION at Mesa's top-level, then
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commit this change.
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</p>
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<h3>Create release notes for the new release</h3>
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<p>
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Create a new file docs/relnotes/X.Y.Z.html, (follow the style of the previous
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release notes). Note that the sha256sums section of the release notes should
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be empty at this point.
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</p>
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<p>
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Two scripts are available to help generate portions of the release notes:
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<pre>
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./bin/bugzilla_mesa.sh
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./bin/shortlog_mesa.sh
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</pre>
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<p>
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The first script identifies commits that reference bugzilla bugs and obtains
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the descriptions of those bugs from bugzilla. The second script generates a
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log of all commits. In both cases, HTML-formatted lists are printed to stdout
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to be included in the release notes.
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</p>
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<p>
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Commit these changes
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</p>
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<h3>Make the release archives, signatures, and the release tag</h3>
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<p>
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From inside the Mesa directory:
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<pre>
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./autogen.sh
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make -j1 tarballs
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</pre>
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<p>
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After the tarballs are created, the sha256 checksums for the files will
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be computed and printed. These will be used in a step below.
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</p>
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<p>
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It's important at this point to also verify that the constructed tar file
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actually builds:
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</p>
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<pre>
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tar xjf MesaLib-X.Y.Z.tar.bz2
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cd Mesa-X.Y.Z
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./configure --enable-gallium-llvm
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make -j6
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make install
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</pre>
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<p>
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Some touch testing should also be performed at this point, (run glxgears or
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more involved OpenGL programs against the installed Mesa).
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</p>
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<p>
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Create detached GPG signatures for each of the archive files created above:
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</p>
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<pre>
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gpg --sign --detach MesaLib-X.Y.Z.tar.gz
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gpg --sign --detach MesaLib-X.Y.Z.tar.bz2
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gpg --sign --detach MesaLib-X.Y.Z.zip
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</pre>
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<p>
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Tag the commit used for the build:
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</p>
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<pre>
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git tag -s mesa-X.Y.X -m "Mesa X.Y.Z release"
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</pre>
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<p>
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Note: It would be nice to investigate and fix the issue that causes the
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tarballs target to fail with multiple build process, such as with "-j4". It
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would also be nice to incorporate all of the above commands into a single
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makefile target. And instead of a custom "tarballs" target, we should
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incorporate things into the standard "make dist" and "make distcheck" targets.
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</p>
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<h3>Add the sha256sums to the release notes</h3>
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<p>
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Edit docs/relnotes/X.Y.Z.html to add the sha256sums printed as part of "make
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tarballs" in the previous step. Commit this change.
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</p>
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<h3>Push all commits and the tag creates above</h3>
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<p>
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This is the first step that cannot easily be undone. The release is going
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forward from this point:
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</p>
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<pre>
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git push origin X.Y --tags
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</pre>
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<h3>Install the release files and signatures on the distribution server</h3>
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<p>
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The following commands can be used to copy the release archive files and
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signatures to the freedesktop.org server:
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</p>
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<pre>
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scp MesaLib-X.Y.Z* people.freedesktop.org:
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ssh people.freedesktop.org
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cd /srv/ftp.freedesktop.org/pub/mesa
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mkdir X.Y.Z
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cd X.Y.Z
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mv ~/MesaLib-X.Y.Z* .
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</pre>
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<h3>Back on mesa master, andd the new release notes into the tree</h3>
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<p>
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Something like the following steps will do the trick:
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</p>
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<pre>
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cp docs/relnotes/X.Y.Z.html /tmp
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git checkout master
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cp /tmp/X.Y.Z.html docs/relnotes
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git add docs/relnotes/X.Y.Z.html
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</pre>
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<p>
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Also, edit docs/relnotes.html to add a link to the new release notes, and edit
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docs/index.html to add a news entry. Then commit and push:
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</p>
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<pre>
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git commit -a -m "docs: Import X.Y.Z release notes, add news item."
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git push origin
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</pre>
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<h3>Update the mesa3d.org website</h3>
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<p>
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NOTE: The recent release managers have not been performing this step
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themselves, but leaving this to Brian Paul, (who has access to the
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sourceforge.net hosting for mesa3d.org). Brian is more than willing to grant
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the permission necessary to future release managers to do this step on their
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own.
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</p>
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|
|
<p>
|
|
Update the web site by copying the docs/ directory's files to
|
|
/home/users/b/br/brianp/mesa-www/htdocs/ with:
|
|
<br>
|
|
<code>
|
|
sftp USERNAME,mesa3d@web.sourceforge.net
|
|
</code>
|
|
</p>
|
|
|
|
|
|
<h3>Announce the release</h3>
|
|
<p>
|
|
Make an announcement on the mailing lists:
|
|
|
|
<em>mesa-dev@lists.freedesktop.org</em>,
|
|
and
|
|
<em>mesa-announce@lists.freedesktop.org</em>
|
|
|
|
Follow the template of previously-sent release announcements. The following
|
|
command can be used to generate the log of changes to be included in the
|
|
release announcement:
|
|
|
|
<pre>
|
|
git shortlog mesa-X.Y.Z-1..mesa-X.Y.Z
|
|
</pre>
|
|
</p>
|
|
|
|
</div>
|
|
</body>
|
|
</html>
|