summaryrefslogtreecommitdiff
blob: c9503e91d5005e5190afa12e31c74d75ef479d0e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
<!DOCTYPE html>

<html xmlns="http://www.w3.org/1999/xhtml">
  <head>
    <meta charset="utf-8" />
    <title>Language-specific policies &#8212; Gentoo Policy Guide  documentation</title>
    <link rel="stylesheet" href="_static/alabaster.css" type="text/css" />
    <link rel="stylesheet" href="_static/pygments.css" type="text/css" />
    <script type="text/javascript" id="documentation_options" data-url_root="./" src="_static/documentation_options.js"></script>
    <script type="text/javascript" src="_static/jquery.js"></script>
    <script type="text/javascript" src="_static/underscore.js"></script>
    <script type="text/javascript" src="_static/doctools.js"></script>
    <script type="text/javascript" src="_static/language_data.js"></script>
    <link rel="index" title="Index" href="genindex.html" />
    <link rel="search" title="Search" href="search.html" />
    <link rel="next" title="Other metadata variables" href="other-metadata.html" />
    <link rel="prev" title="Keywording and stabilization" href="keywords.html" />
   
  <link rel="stylesheet" href="_static/custom.css" type="text/css" />
  
  
  <meta name="viewport" content="width=device-width, initial-scale=0.9, maximum-scale=0.9" />

  </head><body>
  

    <div class="document">
      <div class="documentwrapper">
        <div class="bodywrapper">
          

          <div class="body" role="main">
            
  <div class="section" id="language-specific-policies">
<h1>Language-specific policies<a class="headerlink" href="#language-specific-policies" title="Permalink to this headline"></a></h1>
<div class="section" id="python">
<span id="index-0"></span><h2>Python<a class="headerlink" href="#python" title="Permalink to this headline"></a></h2>
<span class="target" id="index-1"></span><span class="target" id="index-2"></span><span class="target" id="index-3"></span><div class="section" id="eclass-usage">
<span id="index-4"></span><h3>Eclass usage<a class="headerlink" href="#eclass-usage" title="Permalink to this headline"></a></h3>
<dl class="field-list simple">
<dt class="field-odd">Source</dt>
<dd class="field-odd"><p>Python project</p>
</dd>
<dt class="field-even">Reference</dt>
<dd class="field-even"><p><a class="reference external" href="https://wiki.gentoo.org/wiki/Project:Python/Eclasses">https://wiki.gentoo.org/wiki/Project:Python/Eclasses</a></p>
</dd>
<dt class="field-odd">Reported</dt>
<dd class="field-odd"><p>by pkgcheck</p>
</dd>
</dl>
<p>All packages using Python (either through installing Python modules
or scripts, linking to libpython, calling Python at runtime or build
time) must do it through one of the python-r1 eclasses.  Packages must
not directly depend on Python, directly use PYTHON_SINGLE_TARGET
or PYTHON_TARGETS.  The variables and functions provided by the eclasses
must be used instead.</p>
<p>All ebuilds must explicitly define supported Python implementations
in PYTHON_COMPAT.  Dependencies between Python packages must use
PYTHON_USEDEP, PYTHON_SINGLE_USEDEP or python_gen_cond_dep in order
to ensure implementation match.</p>
<p><em>Rationale</em>: the eclass code guarantees consistent and reliable handling
of slotted Python.  It ensures that the whole dependency graph uses
matching implementation and that programs will not accidentally break
if user changes his Python preferences.  The helper functions
and variables also make it possible to gracefully retire old
implementations with minimal changes to existing ebuilds.</p>
</div>
<div class="section" id="python-2-deprecation">
<span id="index-5"></span><h3>Python 2 deprecation<a class="headerlink" href="#python-2-deprecation" title="Permalink to this headline"></a></h3>
<dl class="field-list simple">
<dt class="field-odd">Source</dt>
<dd class="field-odd"><p>Python project</p>
</dd>
<dt class="field-even">Reference</dt>
<dd class="field-even"><p><a class="reference external" href="https://wiki.gentoo.org/wiki/Project:Python#Python_2_end-of-life">https://wiki.gentoo.org/wiki/Project:Python#Python_2_end-of-life</a></p>
</dd>
<dt class="field-odd">Reported</dt>
<dd class="field-odd"><p>no</p>
</dd>
</dl>
<p>Python 2 is being phased out of Gentoo packages.  Python 2 support
must not be introduced in new packages, unless explicitly required
to maintain compatibility with existing packages.  Packages that do not
support Python 3 should be removed sooner or later, depending
on Python 3 porting chances.</p>
<p>In packages that support both Python 2 and Python 3, the Python 2
support should be gracefully retired, as soon as their reverse
dependencies are ready or removed.</p>
<p><em>Rationale</em>: Python 2 has reached its (deferred) end-of-life by the end
of 2019.  Many important upstream projects have already removed support
for Python 2.  Those packages are frequently dependencies of other
packages, causing the cost of maintaining Python 2 support to grow
exponentially.</p>
<p>Early removal of unnecessary Python 2 support will both reduce
the long-term maintenance costs, and give users better chance to prepare
than delaying it until the number of packages losing Python 2 support
will cause major upgrade issues.</p>
</div>
</div>
</div>


          </div>
          
        </div>
      </div>
      <div class="sphinxsidebar" role="navigation" aria-label="main navigation">
        <div class="sphinxsidebarwrapper">
<h1 class="logo"><a href="index.html">Gentoo Policy Guide</a></h1>








<h3>Navigation</h3>
<p class="caption"><span class="caption-text">Contents:</span></p>
<ul class="current">
<li class="toctree-l1"><a class="reference internal" href="preface.html">Preface</a></li>
<li class="toctree-l1"><a class="reference internal" href="motivation.html">Motivation and history</a></li>
<li class="toctree-l1"><a class="reference internal" href="basics.html">Basic information</a></li>
<li class="toctree-l1"><a class="reference internal" href="other-docs.html">Other policy documents</a></li>
<li class="toctree-l1"><a class="reference internal" href="dependencies.html">Dependencies</a></li>
<li class="toctree-l1"><a class="reference internal" href="ebuild-format.html">Ebuild file format</a></li>
<li class="toctree-l1"><a class="reference internal" href="filesystem.html">File system layout</a></li>
<li class="toctree-l1"><a class="reference internal" href="installed-files.html">Installed files</a></li>
<li class="toctree-l1"><a class="reference internal" href="keywords.html">Keywording and stabilization</a></li>
<li class="toctree-l1 current"><a class="current reference internal" href="#">Language-specific policies</a><ul>
<li class="toctree-l2"><a class="reference internal" href="#python">Python</a></li>
</ul>
</li>
<li class="toctree-l1"><a class="reference internal" href="other-metadata.html">Other metadata variables</a></li>
<li class="toctree-l1"><a class="reference internal" href="use-flags.html">USE flags</a></li>
<li class="toctree-l1"><a class="reference internal" href="user-group.html">Users and groups</a></li>
</ul>

<div class="relations">
<h3>Related Topics</h3>
<ul>
  <li><a href="index.html">Documentation overview</a><ul>
      <li>Previous: <a href="keywords.html" title="previous chapter">Keywording and stabilization</a></li>
      <li>Next: <a href="other-metadata.html" title="next chapter">Other metadata variables</a></li>
  </ul></li>
</ul>
</div>
<div id="searchbox" style="display: none" role="search">
  <h3 id="searchlabel">Quick search</h3>
    <div class="searchformwrapper">
    <form class="search" action="search.html" method="get">
      <input type="text" name="q" aria-labelledby="searchlabel" />
      <input type="submit" value="Go" />
    </form>
    </div>
</div>
<script type="text/javascript">$('#searchbox').show(0);</script>








        </div>
      </div>
      <div class="clearer"></div>
    </div>
    <div class="footer">
      &copy;2020, Gentoo Authors.
      
      |
      Powered by <a href="http://sphinx-doc.org/">Sphinx 2.3.1</a>
      &amp; <a href="https://github.com/bitprophet/alabaster">Alabaster 0.7.12</a>
      
      |
      <a href="_sources/languages.rst.txt"
          rel="nofollow">Page source</a>
    </div>

    

    
  </body>
</html>