Modify the Python 3 stubs for requests to be Python 2-compatible

This works towards fixing #924. To make the changes easier to review, I'm planning to
fix the issue in two steps:
- This commit makes the 3 stubs compatible with py2
- The next PR will move the 3 stubs to 2and3 and remove the 2 stubs

I wrote this code by diffing the files in third_party/{2,3}/requests and making
appropriate changes to the Python 3 stubs (mostly str/Text stuff). I verified
that the 3 stubs now pass mypy when parsed as 2.7, but I don't have an annotated
requests-using codebase to test on.

third_party/3/requests/adapters.pyi

@@ -1,6 +1,6 @@
 # Stubs for requests.adapters (Python 3)
 
-from typing import Any, Container, Union, Tuple
+from typing import Any, Container, Union, Text, Tuple
 from . import models
 from .packages.urllib3 import poolmanager
 from .packages.urllib3 import response
@@ -47,7 +47,7 @@ class BaseAdapter:
     def send(self, request: PreparedRequest, stream: bool=False,
              timeout: Union[None, float, Tuple[float, float]]=None,
              verify: bool=False,
-             cert: Union[None, Union[str, bytes], Container[Union[str, bytes]]]=None
+             cert: Union[None, Union[bytes, Text], Container[Union[bytes, Text]]]=None
              ) -> Response: ...
     def close(self) -> None: ...
 class HTTPAdapter(BaseAdapter):

third_party/3/requests/api.pyi

@@ -4,24 +4,23 @@ from typing import Optional, Union, Any, Iterable, Mapping, MutableMapping, Tupl
 
 from .models import Response
 
-_ParamsMappingValueType = Union[str, bytes, int, float, Iterable[Union[str, bytes, int, float]]]
+_ParamsMappingValueType = Union[Text, bytes, int, float, Iterable[Union[Text, bytes, int, float]]]
 _Data = Union[None, bytes, MutableMapping[Text, Text], IO]
 
 def request(method: str, url: str, **kwargs) -> Response: ...
-def get(url: Union[str, bytes],
+def get(url: Union[Text, bytes],
         params: Optional[
-            Union[
-                Mapping[Union[str, bytes, int, float], _ParamsMappingValueType],
-                Union[str, bytes],
-                Tuple[Union[str, bytes, int, float], _ParamsMappingValueType],
-                Mapping[str, _ParamsMappingValueType],
-                Mapping[bytes, _ParamsMappingValueType],
-                Mapping[int, _ParamsMappingValueType],
-                Mapping[float, _ParamsMappingValueType]]]=None,
+            Union[Mapping[Union[Text, bytes, int, float], _ParamsMappingValueType],
+                  Union[Text, bytes],
+                  Tuple[Union[Text, bytes, int, float], _ParamsMappingValueType],
+                  Mapping[Text, _ParamsMappingValueType],
+                  Mapping[bytes, _ParamsMappingValueType],
+                  Mapping[int, _ParamsMappingValueType],
+                  Mapping[float, _ParamsMappingValueType]]] = None,
         **kwargs) -> Response: ...
-def options(url: str, **kwargs) -> Response: ...
-def head(url: str, **kwargs) -> Response: ...
-def post(url: str, data: _Data = ..., json: Optional[MutableMapping] = ..., **kwargs) -> Response: ...
-def put(url: str, data: _Data = ..., **kwargs) -> Response: ...
-def patch(url: str, data: _Data = ..., **kwargs) -> Response: ...
-def delete(url: str, **kwargs) -> Response: ...
+def options(url: Union[str, Text], **kwargs) -> Response: ...
+def head(url: Union[str, Text], **kwargs) -> Response: ...
+def post(url: Union[str, Text], data: _Data = ..., json: Optional[MutableMapping] = ..., **kwargs) -> Response: ...
+def put(url: Union[str, Text], data: _Data = ..., **kwargs) -> Response: ...
+def patch(url: Union[str, Text], data: _Data = ..., **kwargs) -> Response: ...
+def delete(url: Union[str, Text], **kwargs) -> Response: ...

third_party/3/requests/cookies.pyi

@@ -1,12 +1,14 @@
 # Stubs for requests.cookies (Python 3)
 
+import sys
 from typing import Any, MutableMapping
-# import cookielib
-from http import cookiejar as cookielib
 import collections
 from . import compat
 
-# cookielib = compat.cookielib
+if sys.version_info < (3, 0):
+    from cookielib import CookieJar
+else:
+    from http.cookiejar import CookieJar
 
 class MockRequest:
     type = ...  # type: Any
@@ -39,7 +41,7 @@ def remove_cookie_by_name(cookiejar, name, domain=..., path=...): ...
 
 class CookieConflictError(RuntimeError): ...
 
-class RequestsCookieJar(cookielib.CookieJar, MutableMapping):
+class RequestsCookieJar(CookieJar, MutableMapping):
     def get(self, name, default=..., domain=..., path=...): ...
     def set(self, name, value, **kwargs): ...
     def iterkeys(self): ...

third_party/3/requests/models.pyi

@@ -1,6 +1,6 @@
 # Stubs for requests.models (Python 3)
 
-from typing import Any, List, MutableMapping, Iterator, Dict
+from typing import Any, List, MutableMapping, Iterator, Dict, Text
 import datetime
 
 from . import hooks
@@ -80,10 +80,10 @@ class Request(RequestHooksMixin):
     def prepare(self): ...
 
 class PreparedRequest(RequestEncodingMixin, RequestHooksMixin):
-    method = ...  # type: Optional[str]
-    url = ...  # type: Optional[str]
+    method = ...  # type: Optional[Union[str, Text]]
+    url = ...  # type: Optional[Union[str, Text]]
     headers = ...  # type: CaseInsensitiveDict
-    body = ...  # type: Optional[Union[str, bytes]]
+    body = ...  # type: Optional[Union[bytes, Text]]
     hooks = ...  # type: Any
     def __init__(self) -> None: ...
     def prepare(self, method=..., url=..., headers=..., files=..., data=..., params=...,

third_party/3/requests/packages/urllib3/connection.pyi

@@ -1,21 +1,28 @@
 # Stubs for requests.packages.urllib3.connection (Python 3.4)
 
+import sys
 from typing import Any
 from . import packages
-from http.client import HTTPConnection as _HTTPConnection
 import ssl
-# from httplib import HTTPConnection as _HTTPConnection # python 2
 from . import exceptions
 from .packages import ssl_match_hostname
 from .util import ssl_
 from . import util
-import http.client
+
+if sys.version_info <= (3, 0):
+    from httplib import HTTPConnection as _HTTPConnection
+    from httplib import HTTPException as HTTPException
+
+    class ConnectionError(Exception): ...
+else:
+    from http.client import HTTPConnection as _HTTPConnection
+    from http.client import HTTPException as HTTPException
+    from builtins import ConnectionError as ConnectionError
+
 
 class DummyConnection: ...
 
 BaseSSLError = ssl.SSLError
-ConnectionError = __builtins__.ConnectionError
-HTTPException = http.client.HTTPException
 
 ConnectTimeoutError = exceptions.ConnectTimeoutError
 SystemTimeWarning = exceptions.SystemTimeWarning
@@ -61,4 +68,4 @@ class VerifiedHTTPSConnection(HTTPSConnection):
     is_verified = ...  # type: Any
     def connect(self): ...
 
-UnverifiedHTTPSConnection = ...  # type: Any
+UnverifiedHTTPSConnection = HTTPSConnection

third_party/3/requests/packages/urllib3/response.pyi

@@ -2,11 +2,9 @@
 #
 # NOTE: This dynamically typed stub was automatically generated by stubgen.
 
-from typing import Any
-import io
+from typing import Any, IO
 from . import _collections
 from . import exceptions
-# from .packages import six
 from .connection import HTTPException as HTTPException, BaseSSLError as BaseSSLError
 from .util import response
 
@@ -28,7 +26,7 @@ class GzipDecoder:
     def __getattr__(self, name): ...
     def decompress(self, data): ...
 
-class HTTPResponse(io.IOBase):
+class HTTPResponse(IO[Any]):
     CONTENT_DECODERS = ...  # type: Any
     REDIRECT_STATUSES = ...  # type: Any
     headers = ...  # type: Any

third_party/3/requests/sessions.pyi

@@ -92,19 +92,19 @@ class Session(SessionRedirectMixin):
                 cert: Union[Text, Tuple[Text, Text], None] = ...,
                 json: Optional[MutableMapping] = ...,
                 ) -> Response: ...
-    def get(self, url: Union[str, bytes], **kwargs) -> Response: ...
-    def options(self, url: Union[str, bytes], **kwargs) -> Response: ...
-    def head(self, url: Union[str, bytes], **kwargs) -> Response: ...
-    def post(self, url: Union[str, bytes], data: _Data = ..., json: Optional[MutableMapping] = ..., **kwargs) -> Response: ...
-    def put(self, url: Union[str, bytes], data: _Data = ..., **kwargs) -> Response: ...
-    def patch(self, url: Union[str, bytes], data: _Data = ..., **kwargs) -> Response: ...
-    def delete(self, url: Union[str, bytes], **kwargs) -> Response: ...
+    def get(self, url: Union[Text, bytes], **kwargs) -> Response: ...
+    def options(self, url: Union[Text, bytes], **kwargs) -> Response: ...
+    def head(self, url: Union[Text, bytes], **kwargs) -> Response: ...
+    def post(self, url: Union[Text, bytes], data: _Data = ..., json: Optional[MutableMapping] = ..., **kwargs) -> Response: ...
+    def put(self, url: Union[Text, bytes], data: _Data = ..., **kwargs) -> Response: ...
+    def patch(self, url: Union[Text, bytes], data: _Data = ..., **kwargs) -> Response: ...
+    def delete(self, url: Union[Text, bytes], **kwargs) -> Response: ...
     def send(self, request, **kwargs): ...
     def merge_environment_settings(self, url, proxies, stream, verify, cert): ...
     def get_adapter(self, url): ...
     def close(self) -> None: ...
     def mount(self, prefix:
-              Union[str, bytes],
+              Union[Text, bytes],
               adapter: BaseAdapter) -> None: ...
 
 def session() -> Session: ...

third_party/3/requests/structures.pyi

@@ -1,9 +1,9 @@
 # Stubs for requests.structures (Python 3)
 
-from typing import Any, Iterator, MutableMapping, Tuple, Union
+from typing import Any, Iterator, MutableMapping, Text, Tuple, Union
 
-class CaseInsensitiveDict(MutableMapping[str, Union[str, bytes]]):
-    def lower_items(self) -> Iterator[Tuple[str, Union[str, bytes]]]: ...
+class CaseInsensitiveDict(MutableMapping[str, Union[Text, bytes]]):
+    def lower_items(self) -> Iterator[Tuple[str, Union[Text, bytes]]]: ...
 
 class LookupDict(dict):
     name = ...  # type: Any