Update urllib3-1.26.7

lib/urllib3/_collections.py

@@ -1,8 +1,13 @@
 from __future__ import absolute_import
-from collections import Mapping, MutableMapping
+
+try:
+    from collections.abc import Mapping, MutableMapping
+except ImportError:
+    from collections import Mapping, MutableMapping
 try:
     from threading import RLock
 except ImportError:  # Platform-specific: No threads available
+
     class RLock:
         def __enter__(self):
             pass
@@ -11,14 +16,13 @@ except ImportError:  # Platform-specific: No threads available
             pass
 
 
-try:  # Python 2.7+
-    from collections import OrderedDict
-except ImportError:
-    from .packages.ordered_dict import OrderedDict
-from .packages.six import iterkeys, itervalues, PY3
+from collections import OrderedDict
 
+from .exceptions import InvalidHeader
+from .packages import six
+from .packages.six import iterkeys, itervalues
 
-__all__ = ['RecentlyUsedContainer', 'HTTPHeaderDict']
+__all__ = ["RecentlyUsedContainer", "HTTPHeaderDict"]
 
 
 _Null = object()
@@ -81,7 +85,9 @@ class RecentlyUsedContainer(MutableMapping):
             return len(self._container)
 
     def __iter__(self):
-        raise NotImplementedError('Iteration over this class is unlikely to be threadsafe.')
+        raise NotImplementedError(
+            "Iteration over this class is unlikely to be threadsafe."
+        )
 
     def clear(self):
         with self.lock:
@@ -149,7 +155,7 @@ class HTTPHeaderDict(MutableMapping):
 
     def __getitem__(self, key):
         val = self._container[key.lower()]
-        return ', '.join(val[1:])
+        return ", ".join(val[1:])
 
     def __delitem__(self, key):
         del self._container[key.lower()]
@@ -158,17 +164,18 @@ class HTTPHeaderDict(MutableMapping):
         return key.lower() in self._container
 
     def __eq__(self, other):
-        if not isinstance(other, Mapping) and not hasattr(other, 'keys'):
+        if not isinstance(other, Mapping) and not hasattr(other, "keys"):
             return False
         if not isinstance(other, type(self)):
             other = type(self)(other)
-        return (dict((k.lower(), v) for k, v in self.itermerged()) ==
-                dict((k.lower(), v) for k, v in other.itermerged()))
+        return dict((k.lower(), v) for k, v in self.itermerged()) == dict(
+            (k.lower(), v) for k, v in other.itermerged()
+        )
 
     def __ne__(self, other):
         return not self.__eq__(other)
 
-    if not PY3:  # Python 2
+    if six.PY2:  # Python 2
         iterkeys = MutableMapping.iterkeys
         itervalues = MutableMapping.itervalues
 
@@ -183,9 +190,9 @@ class HTTPHeaderDict(MutableMapping):
             yield vals[0]
 
     def pop(self, key, default=__marker):
-        '''D.pop(k[,d]) -> v, remove specified key and return the corresponding value.
-          If key is not found, d is returned if given, otherwise KeyError is raised.
-        '''
+        """D.pop(k[,d]) -> v, remove specified key and return the corresponding value.
+        If key is not found, d is returned if given, otherwise KeyError is raised.
+        """
         # Using the MutableMapping function directly fails due to the private marker.
         # Using ordinary dict.pop would expose the internal structures.
         # So let's reinvent the wheel.
@@ -227,8 +234,10 @@ class HTTPHeaderDict(MutableMapping):
         with self.add instead of self.__setitem__
         """
         if len(args) > 1:
-            raise TypeError("extend() takes at most 1 positional "
-                            "arguments ({0} given)".format(len(args)))
+            raise TypeError(
+                "extend() takes at most 1 positional "
+                "arguments ({0} given)".format(len(args))
+            )
         other = args[0] if len(args) >= 1 else ()
 
         if isinstance(other, HTTPHeaderDict):
@@ -294,7 +303,7 @@ class HTTPHeaderDict(MutableMapping):
         """Iterate over all headers, merging duplicate ones together."""
         for key in self:
             val = self._container[key.lower()]
-            yield val[0], ', '.join(val[1:])
+            yield val[0], ", ".join(val[1:])
 
     def items(self):
         return list(self.iteritems())
@@ -305,15 +314,24 @@ class HTTPHeaderDict(MutableMapping):
         # python2.7 does not expose a proper API for exporting multiheaders
         # efficiently. This function re-reads raw lines from the message
         # object and extracts the multiheaders properly.
+        obs_fold_continued_leaders = (" ", "\t")
         headers = []
 
         for line in message.headers:
-            if line.startswith((' ', '\t')):
-                key, value = headers[-1]
-                headers[-1] = (key, value + '\r\n' + line.rstrip())
-                continue
+            if line.startswith(obs_fold_continued_leaders):
+                if not headers:
+                    # We received a header line that starts with OWS as described
+                    # in RFC-7230 S3.2.4. This indicates a multiline header, but
+                    # there exists no previous header to which we can attach it.
+                    raise InvalidHeader(
+                        "Header continuation with no previous header: %s" % line
+                    )
+                else:
+                    key, value = headers[-1]
+                    headers[-1] = (key, value + " " + line.strip())
+                    continue
 
-            key, value = line.split(':', 1)
+            key, value = line.split(":", 1)
             headers.append((key, value.strip()))
 
         return cls(headers)