Enable flake8-bugbear, but disable most checks. (matrix-org#9499)

* Adds B00 to ignored checks.
* Fixes remaining issues.

changelog.d/9499.misc

@@ -0,0 +1 @@
+Introduce bugbear to the test suite and fix some of it's lint violations.

setup.cfg

@@ -18,7 +18,8 @@ ignore =
 #  E203: whitespace before ':' (which is contrary to pep8?)
 #  E731: do not assign a lambda expression, use a def
 #  E501: Line too long (black enforces this for us)
-ignore=W503,W504,E203,E731,E501
+#   B00: Subsection of the bugbear suite (TODO: add in remaining fixes)
+ignore=W503,W504,E203,E731,E501,B00
 
 [isort]
 line_length = 88

setup.py

@@ -99,6 +99,7 @@ def exec_file(path_segments):
     "isort==5.7.0",
     "black==20.8b1",
     "flake8-comprehensions",
+    "flake8-bugbear",
     "flake8",
 ]
 

synapse/app/__init__.py

@@ -22,7 +22,9 @@
 try:
     python_dependencies.check_requirements()
 except python_dependencies.DependencyException as e:
-    sys.stderr.writelines(e.message)
+    sys.stderr.writelines(
+        e.message  # noqa: B306, DependencyException.message is a property
+    )
     sys.exit(1)
 
 

synapse/config/key.py

@@ -404,7 +404,11 @@ def _parse_key_servers(key_servers, federation_verify_certificates):
     try:
         jsonschema.validate(key_servers, TRUSTED_KEY_SERVERS_SCHEMA)
     except jsonschema.ValidationError as e:
-        raise ConfigError("Unable to parse 'trusted_key_servers': " + e.message)
+        raise ConfigError(
+            "Unable to parse 'trusted_key_servers': {}".format(
+                e.message  # noqa: B306, jsonschema.ValidationError.message is a valid attribute
+            )
+        )
 
     for server in key_servers:
         server_name = server["server_name"]

synapse/config/metrics.py

@@ -56,7 +56,9 @@ def read_config(self, config, **kwargs):
             try:
                 check_requirements("sentry")
             except DependencyException as e:
-                raise ConfigError(e.message)
+                raise ConfigError(
+                    e.message  # noqa: B306, DependencyException.message is a property
+                )
 
             self.sentry_dsn = config["sentry"].get("dsn")
             if not self.sentry_dsn:

synapse/config/oidc_config.py

@@ -42,7 +42,9 @@ def read_config(self, config, **kwargs):
         try:
             check_requirements("oidc")
         except DependencyException as e:
-            raise ConfigError(e.message) from e
+            raise ConfigError(
+                e.message  # noqa: B306, DependencyException.message is a property
+            ) from e
 
         # check we don't have any duplicate idp_ids now. (The SSO handler will also
         # check for duplicates when the REST listeners get registered, but that happens

synapse/config/repository.py

@@ -176,7 +176,9 @@ def read_config(self, config, **kwargs):
                 check_requirements("url_preview")
 
             except DependencyException as e:
-                raise ConfigError(e.message)
+                raise ConfigError(
+                    e.message  # noqa: B306, DependencyException.message is a property
+                )
 
             if "url_preview_ip_range_blacklist" not in config:
                 raise ConfigError(

synapse/config/saml2_config.py

@@ -76,7 +76,9 @@ def read_config(self, config, **kwargs):
         try:
             check_requirements("saml2")
         except DependencyException as e:
-            raise ConfigError(e.message)
+            raise ConfigError(
+                e.message  # noqa: B306, DependencyException.message is a property
+            )
 
         self.saml2_enabled = True
 

synapse/config/tracer.py

@@ -39,7 +39,9 @@ def read_config(self, config, **kwargs):
         try:
             check_requirements("opentracing")
         except DependencyException as e:
-            raise ConfigError(e.message)
+            raise ConfigError(
+                e.message  # noqa: B306, DependencyException.message is a property
+            )
 
         # The tracer is enabled so sanitize the config
 

synapse/crypto/context_factory.py

@@ -219,7 +219,7 @@ def clientConnectionForTLS(self, tls_protocol):
         # ... and we also gut-wrench a '_synapse_tls_verifier' attribute into the
         # tls_protocol so that the SSL context's info callback has something to
         # call to do the cert verification.
-        setattr(tls_protocol, "_synapse_tls_verifier", self._verifier)
+        tls_protocol._synapse_tls_verifier = self._verifier
         return connection
 
 

tests/unittest.py

@@ -140,7 +140,7 @@ def assertObjectHasAttributes(self, attrs, obj):
             try:
                 self.assertEquals(attrs[key], getattr(obj, key))
             except AssertionError as e:
-                raise (type(e))(e.message + " for '.%s'" % key)
+                raise (type(e))("Assert error for '.{}':".format(key)) from e
 
     def assert_dict(self, required, actual):
         """Does a partial assert of a dict.