<p dir="auto">Travis use <code class="notranslate">pip 6.0.7</code><br>
Today we had the following error:</p>
<div class="highlight highlight-source-python notranslate position-relative overflow-auto" dir="auto" data-snippet-clipboard-copy-content="pip install -U requests==2.14.0

Using cached requests-2.14.0-py2.py3-none-any.whl
  Exception:
  Traceback (most recent call last):
    File &quot;/home/travis/virtualenv/python2.7_with_system_site_packages/local/lib/python2.7/site-packages/pip/basecommand.py&quot;, line 232, in main
      status = self.run(options, args)
    File &quot;/home/travis/virtualenv/python2.7_with_system_site_packages/local/lib/python2.7/site-packages/pip/commands/install.py&quot;, line 339, in run
      requirement_set.prepare_files(finder)
    File &quot;/home/travis/virtualenv/python2.7_with_system_site_packages/local/lib/python2.7/site-packages/pip/req/req_set.py&quot;, line 436, in prepare_files
      req_to_install.extras):
    File &quot;/home/travis/virtualenv/python2.7_with_system_site_packages/local/lib/python2.7/site-packages/pip/_vendor/pkg_resources/__init__.py&quot;, line 2496, in requires
      dm = self._dep_map
    File &quot;/home/travis/virtualenv/python2.7_with_system_site_packages/local/lib/python2.7/site-packages/pip/_vendor/pkg_resources/__init__.py&quot;, line 2697, in _dep_map
      self.__dep_map = self._compute_dependencies()
    File &quot;/home/travis/virtualenv/python2.7_with_system_site_packages/local/lib/python2.7/site-packages/pip/_vendor/pkg_resources/__init__.py&quot;, line 2730, in _compute_dependencies
      common = frozenset(reqs_for_extra(None))
    File &quot;/home/travis/virtualenv/python2.7_with_system_site_packages/local/lib/python2.7/site-packages/pip/_vendor/pkg_resources/__init__.py&quot;, line 2727, in reqs_for_extra
      if req.marker_fn(override={'extra':extra}):
    File &quot;/home/travis/virtualenv/python2.7_with_system_site_packages/local/lib/python2.7/site-packages/pip/_vendor/_markerlib/markers.py&quot;, line 113, in marker_fn
      return eval(compiled_marker, environment)
    File &quot;&lt;environment marker&gt;&quot;, line 1, in &lt;module&gt;
  NameError: name 'platform_system' is not defined"><pre class="notranslate"><span class="pl-s1">pip</span> <span class="pl-s1">install</span> <span class="pl-c1">-</span><span class="pl-v">U</span> <span class="pl-s1">requests</span><span class="pl-c1">==</span><span class="pl-c1">2.14</span>.<span class="pl-c1">0</span>

<span class="pl-v">Using</span> <span class="pl-s1">cached</span> <span class="pl-s1">requests</span><span class="pl-c1">-</span><span class="pl-c1">2.14</span>.<span class="pl-c1">0</span><span class="pl-c1">-</span><span class="pl-s1">py2</span>.<span class="pl-s1">py3</span><span class="pl-c1">-</span><span class="pl-s1">none</span><span class="pl-c1">-</span><span class="pl-s1">any</span>.<span class="pl-s1">whl</span>
  <span class="pl-v">Exception</span>:
  <span class="pl-v">Traceback</span> (<span class="pl-s1">most</span> <span class="pl-s1">recent</span> <span class="pl-s1">call</span> <span class="pl-s1">last</span>):
    <span class="pl-v">File</span> <span class="pl-s">"/home/travis/virtualenv/python2.7_with_system_site_packages/local/lib/python2.7/site-packages/pip/basecommand.py"</span>, <span class="pl-s1">line</span> <span class="pl-c1">232</span>, <span class="pl-c1">in</span> <span class="pl-s1">main</span>
      <span class="pl-s1">status</span> <span class="pl-c1">=</span> <span class="pl-s1">self</span>.<span class="pl-en">run</span>(<span class="pl-s1">options</span>, <span class="pl-s1">args</span>)
    <span class="pl-v">File</span> <span class="pl-s">"/home/travis/virtualenv/python2.7_with_system_site_packages/local/lib/python2.7/site-packages/pip/commands/install.py"</span>, <span class="pl-s1">line</span> <span class="pl-c1">339</span>, <span class="pl-s1">in</span> <span class="pl-s1">run</span>
      <span class="pl-s1">requirement_set</span>.<span class="pl-en">prepare_files</span>(<span class="pl-s1">finder</span>)
    <span class="pl-v">File</span> <span class="pl-s">"/home/travis/virtualenv/python2.7_with_system_site_packages/local/lib/python2.7/site-packages/pip/req/req_set.py"</span>, <span class="pl-s1">line</span> <span class="pl-c1">436</span>, <span class="pl-s1">in</span> <span class="pl-s1">prepare_files</span>
      <span class="pl-s1">req_to_install</span>.<span class="pl-s1">extras</span>):
    <span class="pl-v">File</span> <span class="pl-s">"/home/travis/virtualenv/python2.7_with_system_site_packages/local/lib/python2.7/site-packages/pip/_vendor/pkg_resources/__init__.py"</span>, <span class="pl-s1">line</span> <span class="pl-c1">2496</span>, <span class="pl-c1">in</span> <span class="pl-s1">requires</span>
      <span class="pl-s1">dm</span> <span class="pl-c1">=</span> <span class="pl-s1">self</span>.<span class="pl-s1">_dep_map</span>
    <span class="pl-v">File</span> <span class="pl-s">"/home/travis/virtualenv/python2.7_with_system_site_packages/local/lib/python2.7/site-packages/pip/_vendor/pkg_resources/__init__.py"</span>, <span class="pl-s1">line</span> <span class="pl-c1">2697</span>, <span class="pl-s1">in</span> <span class="pl-s1">_dep_map</span>
      <span class="pl-s1">self</span>.<span class="pl-s1">__dep_map</span> <span class="pl-c1">=</span> <span class="pl-s1">self</span>.<span class="pl-en">_compute_dependencies</span>()
    <span class="pl-v">File</span> <span class="pl-s">"/home/travis/virtualenv/python2.7_with_system_site_packages/local/lib/python2.7/site-packages/pip/_vendor/pkg_resources/__init__.py"</span>, <span class="pl-s1">line</span> <span class="pl-c1">2730</span>, <span class="pl-s1">in</span> <span class="pl-s1">_compute_dependencies</span>
      <span class="pl-s1">common</span> <span class="pl-c1">=</span> <span class="pl-en">frozenset</span>(<span class="pl-en">reqs_for_extra</span>(<span class="pl-c1">None</span>))
    <span class="pl-v">File</span> <span class="pl-s">"/home/travis/virtualenv/python2.7_with_system_site_packages/local/lib/python2.7/site-packages/pip/_vendor/pkg_resources/__init__.py"</span>, <span class="pl-s1">line</span> <span class="pl-c1">2727</span>, <span class="pl-s1">in</span> <span class="pl-s1">reqs_for_extra</span>
      <span class="pl-k">if</span> <span class="pl-s1">req</span>.<span class="pl-en">marker_fn</span>(<span class="pl-s1">override</span><span class="pl-c1">=</span>{<span class="pl-s">'extra'</span>:<span class="pl-s1">extra</span>}):
    <span class="pl-v">File</span> <span class="pl-s">"/home/travis/virtualenv/python2.7_with_system_site_packages/local/lib/python2.7/site-packages/pip/_vendor/_markerlib/markers.py"</span>, <span class="pl-s1">line</span> <span class="pl-c1">113</span>, <span class="pl-s1">in</span> <span class="pl-s1">marker_fn</span>
      <span class="pl-k">return</span> <span class="pl-en">eval</span>(<span class="pl-s1">compiled_marker</span>, <span class="pl-s1">environment</span>)
    <span class="pl-v">File</span> <span class="pl-s">"&lt;environment marker&gt;"</span>, <span class="pl-s1">line</span> <span class="pl-c1">1</span>, <span class="pl-s1">in</span> <span class="pl-c1">&lt;</span><span class="pl-s1">module</span><span class="pl-c1">&gt;</span>
  <span class="pl-v">NameError</span>: <span class="pl-s1">name</span> <span class="pl-s">'platform_system'</span> <span class="pl-c1">is</span> <span class="pl-c1">not</span> <span class="pl-s1">defined</span></pre></div>
<p dir="auto">We can fix it using:<br>
<code class="notranslate">pip install -U pip</code><br>
<code class="notranslate"># Successfully installed pip-9.0.1</code></p>
<p dir="auto">But maybe too much travis build use default pip version<br>
Could be dual compatibility this requests package?</p>
<p dir="auto">We had a similar fix for pylint: <a class="issue-link js-issue-link" data-error-text="Failed to load title" data-id="172792410" data-permission-text="Title is private" data-url="https://github.com/pylint-dev/astroid/issues/360" data-hovercard-type="pull_request" data-hovercard-url="/pylint-dev/astroid/pull/360/hovercard" href="https://github.com/pylint-dev/astroid/pull/360">pylint-dev/astroid#360</a> based on <a class="issue-link js-issue-link" data-error-text="Failed to load title" data-id="150585499" data-permission-text="Title is private" data-url="https://github.com/pypa/packaging/issues/72" data-hovercard-type="issue" data-hovercard-url="/pypa/packaging/issues/72/hovercard" href="https://github.com/pypa/packaging/issues/72">pypa/packaging#72</a></p>
<p dir="auto">Example with pip 6.1.1 (but same with pip 8.1.1):</p>
<div class="highlight highlight-text-shell-session notranslate position-relative overflow-auto" dir="auto" data-snippet-clipboard-copy-content="&gt; pip install requests
You are using pip version 6.1.1, however version 9.0.1 is available.
You should consider upgrading via the 'pip install --upgrade pip' command.
Collecting requests
  Using cached requests-2.14.0-py2.py3-none-any.whl
  Exception:
  Traceback (most recent call last):
    File &quot;D:\VEnvs\testpip\lib\site-packages\pip\basecommand.py&quot;, line 246, in main
      status = self.run(options, args)
    File &quot;D:\VEnvs\testpip\lib\site-packages\pip\commands\install.py&quot;, line 342, in run
      requirement_set.prepare_files(finder)
    File &quot;D:\VEnvs\testpip\lib\site-packages\pip\req\req_set.py&quot;, line 345, in prepare_files
      functools.partial(self._prepare_file, finder))
    File &quot;D:\VEnvs\testpip\lib\site-packages\pip\req\req_set.py&quot;, line 290, in _walk_req_to_install
      more_reqs = handler(req_to_install)
    File &quot;D:\VEnvs\testpip\lib\site-packages\pip\req\req_set.py&quot;, line 557, in _prepare_file
      set(req_to_install.extras) - set(dist.extras)
    File &quot;D:\VEnvs\testpip\lib\site-packages\pip\_vendor\pkg_resources\__init__.py&quot;, line 2758, in extras
      return [dep for dep in self._dep_map if dep]
    File &quot;D:\VEnvs\testpip\lib\site-packages\pip\_vendor\pkg_resources\__init__.py&quot;, line 2781, in _dep_map
      self.__dep_map = self._compute_dependencies()
    File &quot;D:\VEnvs\testpip\lib\site-packages\pip\_vendor\pkg_resources\__init__.py&quot;, line 2814, in _compute_dependencies
      common = frozenset(reqs_for_extra(None))
    File &quot;D:\VEnvs\testpip\lib\site-packages\pip\_vendor\pkg_resources\__init__.py&quot;, line 2811, in reqs_for_extra
      if req.marker_fn(override={'extra':extra}):
    File &quot;D:\VEnvs\testpip\lib\site-packages\pip\_vendor\_markerlib\markers.py&quot;, line 113, in marker_fn
      return eval(compiled_marker, environment)
    File &quot;&lt;environment marker&gt;&quot;, line 1, in &lt;module&gt;
  NameError: name 'platform_system' is not defined"><pre class="notranslate">&gt; <span class="pl-s1">pip install requests</span>
<span class="pl-c1">You are using pip version 6.1.1, however version 9.0.1 is available.</span>
<span class="pl-c1">You should consider upgrading via the 'pip install --upgrade pip' command.</span>
<span class="pl-c1">Collecting requests</span>
<span class="pl-c1">  Using cached requests-2.14.0-py2.py3-none-any.whl</span>
<span class="pl-c1">  Exception:</span>
<span class="pl-c1">  Traceback (most recent call last):</span>
<span class="pl-c1">    File "D:\VEnvs\testpip\lib\site-packages\pip\basecommand.py", line 246, in main</span>
<span class="pl-c1">      status = self.run(options, args)</span>
<span class="pl-c1">    File "D:\VEnvs\testpip\lib\site-packages\pip\commands\install.py", line 342, in run</span>
<span class="pl-c1">      requirement_set.prepare_files(finder)</span>
<span class="pl-c1">    File "D:\VEnvs\testpip\lib\site-packages\pip\req\req_set.py", line 345, in prepare_files</span>
<span class="pl-c1">      functools.partial(self._prepare_file, finder))</span>
<span class="pl-c1">    File "D:\VEnvs\testpip\lib\site-packages\pip\req\req_set.py", line 290, in _walk_req_to_install</span>
<span class="pl-c1">      more_reqs = handler(req_to_install)</span>
<span class="pl-c1">    File "D:\VEnvs\testpip\lib\site-packages\pip\req\req_set.py", line 557, in _prepare_file</span>
<span class="pl-c1">      set(req_to_install.extras) - set(dist.extras)</span>
<span class="pl-c1">    File "D:\VEnvs\testpip\lib\site-packages\pip\_vendor\pkg_resources\__init__.py", line 2758, in extras</span>
<span class="pl-c1">      return [dep for dep in self._dep_map if dep]</span>
<span class="pl-c1">    File "D:\VEnvs\testpip\lib\site-packages\pip\_vendor\pkg_resources\__init__.py", line 2781, in _dep_map</span>
<span class="pl-c1">      self.__dep_map = self._compute_dependencies()</span>
<span class="pl-c1">    File "D:\VEnvs\testpip\lib\site-packages\pip\_vendor\pkg_resources\__init__.py", line 2814, in _compute_dependencies</span>
<span class="pl-c1">      common = frozenset(reqs_for_extra(None))</span>
<span class="pl-c1">    File "D:\VEnvs\testpip\lib\site-packages\pip\_vendor\pkg_resources\__init__.py", line 2811, in reqs_for_extra</span>
<span class="pl-c1">      if req.marker_fn(override={'extra':extra}):</span>
<span class="pl-c1">    File "D:\VEnvs\testpip\lib\site-packages\pip\_vendor\_markerlib\markers.py", line 113, in marker_fn</span>
<span class="pl-c1">      return eval(compiled_marker, environment)</span>
<span class="pl-c1">    File "&lt;environment marker&gt;", line 1, in &lt;module&gt;</span>
<span class="pl-c1">  NameError: name 'platform_system' is not defined</span></pre></div>
<p dir="auto">So, installing requests 2.14.0 implicitly requires pip &gt;= 9.x. Should be at least in the release note as a disclaimer, or be fixed if it's not on purpose.</p>