<p dir="auto">I am using <code class="notranslate">requests</code> 0.13.1, this code produces the specified exception:</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="  &gt;&gt;&gt; import requests
  &gt;&gt;&gt; s = requests.session()
  &gt;&gt;&gt; s.get(&quot;http:///www.google.com&quot;)
  &gt;&gt;&gt; s.cookies.items()
  [('NID', '61=WDudE-2jKmX8WQjZbiH0QUi__G_kGOVDbs5XCTQO634x51d99mHYi-VptWUURDSJco_IwTTJLAM-Dp_LurBU-WWyz_3xy0BTsMHBJ5Sf6wZrgGwvyDDupLLcA86ypDUt'), ('PREF', 'ID=a7055cc9168cd7d3:FF=0:TM=1341167514:LM=1341167514:S=vbL-Ih__itkxmGxQ'), ('NID', '61=gLhy_qaWV5hZ9VcKxzUXfeJt1yRYmkVzPDVmtbYJshr01gWXNtDSwmHDaRByaNTYWJDzP_z_FjzPhy5EsZ6k74uaZDjX0sUNzgecF7si6Z-50GaemVbN3eNa22Z86T7s'), ('PREF', 'ID=b06021225aa97775:FF=0:TM=1341167515:LM=1341167515:S=wdaMCYeYlNZ-3tnS')]         "><pre class="notranslate"><code class="notranslate">  &gt;&gt;&gt; import requests
  &gt;&gt;&gt; s = requests.session()
  &gt;&gt;&gt; s.get("http:///www.google.com")
  &gt;&gt;&gt; s.cookies.items()
  [('NID', '61=WDudE-2jKmX8WQjZbiH0QUi__G_kGOVDbs5XCTQO634x51d99mHYi-VptWUURDSJco_IwTTJLAM-Dp_LurBU-WWyz_3xy0BTsMHBJ5Sf6wZrgGwvyDDupLLcA86ypDUt'), ('PREF', 'ID=a7055cc9168cd7d3:FF=0:TM=1341167514:LM=1341167514:S=vbL-Ih__itkxmGxQ'), ('NID', '61=gLhy_qaWV5hZ9VcKxzUXfeJt1yRYmkVzPDVmtbYJshr01gWXNtDSwmHDaRByaNTYWJDzP_z_FjzPhy5EsZ6k74uaZDjX0sUNzgecF7si6Z-50GaemVbN3eNa22Z86T7s'), ('PREF', 'ID=b06021225aa97775:FF=0:TM=1341167515:LM=1341167515:S=wdaMCYeYlNZ-3tnS')]         
</code></pre></div>
<p dir="auto">There are two cookies with name <code class="notranslate">NID</code>? It seems like when server update old cookies, session did not update it but insert new one.</p>
<p dir="auto">python 2.7.11<br>
requests installed from pip and up-to-date</p>
<p dir="auto">URL -&gt; '<a href="http://archive.mid.ru/bdomp/zu_r.nsf/strawebeng!OpenView" rel="nofollow">http://archive.mid.ru/bdomp/zu_r.nsf/strawebeng!OpenView</a>'</p>
<p dir="auto">GET request hangs at read time.<br>
I tried to use <code class="notranslate">stream=True</code> and then read from <code class="notranslate">response.raw</code> and it works. But doesn't finish on normal usage.</p>
<p dir="auto">I looked at the headers and the <code class="notranslate">Content-Length</code> is duplicated.<br>
When I try to read it from <code class="notranslate">response.headers['Content-Length']</code> I find a single string: <code class="notranslate">'133172, 133172'</code>.<br>
The length is correct otherwise.</p>
<p dir="auto">I am not entirely sure of what's causing this but my guess is that requests is getting confused by the duplicate header.</p>
<p dir="auto"><em>thanks for everything</em></p>