Replace all remaining six usage with native Python 3 equivalents (#7704)

synapse/http/client.py

@@ -15,11 +15,9 @@
 # limitations under the License.
 
 import logging
+import urllib
 from io import BytesIO
 
-from six import raise_from, text_type
-from six.moves import urllib
-
 import treq
 from canonicaljson import encode_canonical_json, json
 from netaddr import IPAddress
@@ -577,7 +575,7 @@ class SimpleHttpClient(object):
             # This can happen e.g. because the body is too large.
             raise
         except Exception as e:
-            raise_from(SynapseError(502, ("Failed to download remote body: %s" % e)), e)
+            raise SynapseError(502, ("Failed to download remote body: %s" % e)) from e
 
         return (
             length,
@@ -638,7 +636,7 @@ def encode_urlencode_args(args):
 
 
 def encode_urlencode_arg(arg):
-    if isinstance(arg, text_type):
+    if isinstance(arg, str):
         return arg.encode("utf-8")
     elif isinstance(arg, list):
         return [encode_urlencode_arg(i) for i in arg]

synapse/http/matrixfederationclient.py

@@ -17,11 +17,9 @@ import cgi
 import logging
 import random
 import sys
+import urllib
 from io import BytesIO
 
-from six import raise_from, string_types
-from six.moves import urllib
-
 import attr
 import treq
 from canonicaljson import encode_canonical_json
@@ -432,10 +430,10 @@ class MatrixFederationHttpClient(object):
                     except TimeoutError as e:
                         raise RequestSendFailed(e, can_retry=True) from e
                     except DNSLookupError as e:
-                        raise_from(RequestSendFailed(e, can_retry=retry_on_dns_fail), e)
+                        raise RequestSendFailed(e, can_retry=retry_on_dns_fail) from e
                     except Exception as e:
                         logger.info("Failed to send request: %s", e)
-                        raise_from(RequestSendFailed(e, can_retry=True), e)
+                        raise RequestSendFailed(e, can_retry=True) from e
 
                     incoming_responses_counter.labels(
                         request.method, response.code
@@ -487,7 +485,7 @@ class MatrixFederationHttpClient(object):
                         # Retry if the error is a 429 (Too Many Requests),
                         # otherwise just raise a standard HttpResponseException
                         if response.code == 429:
-                            raise_from(RequestSendFailed(e, can_retry=True), e)
+                            raise RequestSendFailed(e, can_retry=True) from e
                         else:
                             raise e
 
@@ -998,7 +996,7 @@ def encode_query_args(args):
 
     encoded_args = {}
     for k, vs in args.items():
-        if isinstance(vs, string_types):
+        if isinstance(vs, str):
             vs = [vs]
         encoded_args[k] = [v.encode("UTF-8") for v in vs]
 

synapse/http/server.py

@@ -16,10 +16,10 @@
 
 import collections
 import html
-import http.client
 import logging
 import types
 import urllib
+from http import HTTPStatus
 from io import BytesIO
 from typing import Awaitable, Callable, TypeVar, Union
 
@@ -188,7 +188,7 @@ def return_html_error(
                 exc_info=(f.type, f.value, f.getTracebackObject()),
             )
     else:
-        code = http.HTTPStatus.INTERNAL_SERVER_ERROR
+        code = HTTPStatus.INTERNAL_SERVER_ERROR
         msg = "Internal server error"
 
         logger.error(