<p dir="auto">requests 2.14+ centos7 py27</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="omeroweb_1  |   Running setup.py egg_info for package requests
omeroweb_1  |     error in requests setup command: Invalid environment marker: platform_system == &quot;Windows&quot; and python_version&lt;&quot;3.3&quot;
omeroweb_1  |     Complete output from command python setup.py egg_info:
omeroweb_1  |     error in requests setup command: Invalid environment marker: platform_system == &quot;Windows&quot; and python_version&lt;&quot;3.3&quot;"><pre class="notranslate"><code class="notranslate">omeroweb_1  |   Running setup.py egg_info for package requests
omeroweb_1  |     error in requests setup command: Invalid environment marker: platform_system == "Windows" and python_version&lt;"3.3"
omeroweb_1  |     Complete output from command python setup.py egg_info:
omeroweb_1  |     error in requests setup command: Invalid environment marker: platform_system == "Windows" and python_version&lt;"3.3"
</code></pre></div>
<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>