fix: Resolve some bug risks and code quality issues (#497)

Changes:
- Fix dangerous default argument in `twilio/base/serialize.py` (PYL-W0102)
- Classmethods should have `cls` as the first arg. in `twilio/jwt/validation/__init__.py` and `twilio/base/page.py` (PYL-C0202)
- Removed unused imports in `tests/unit/http/test_validation_client.py` and `tests/unit/http/test_http_client.py` (PYL-W0611)
- Fix `len()` used as condition in `twilio/request_validator.py` (PYL-C1801)

Also added `.deepsource.toml` configuration file to run continuous static analysis on the repository with DeepSource.

.deepsource.toml

@@ -0,0 +1,25 @@
+version = 1
+
+exclude_patterns = [
+  'examples/**',
+
+  # auto-generated files
+  'twilio/rest/**',
+  'twilio/twiml/**',
+  'tests/integration/**',
+
+  # compat files
+  'twilio/compat.py',
+]
+
+test_patterns = [
+  'tests/**'
+]
+
+[[analyzers]]
+name = "python"
+enabled = true
+
+  [analyzers.meta]
+  max_line_length = 100
+  skip_doc_coverage = ["module", "magic", "class"]

tests/unit/http/test_http_client.py

@@ -1,10 +1,8 @@
 # -*- coding: utf-8 -*-
-import six
-
 import unittest
 
 from mock import patch, Mock
-from requests import Request, Session
+from requests import Session
 
 from twilio.http.http_client import TwilioHttpClient
 from twilio.http.response import Response

tests/unit/http/test_validation_client.py

@@ -2,7 +2,6 @@
 
 import unittest
 
-import mock
 from mock import patch, Mock
 from requests import Request
 from requests import Session

twilio/base/page.py

@@ -48,7 +48,7 @@ def next(self):
         return self.get_instance(next(self._records))
 
     @classmethod
-    def process_response(self, response):
+    def process_response(cls, response):
         """
         Load a JSON response.
 

twilio/base/serialize.py

@@ -39,7 +39,14 @@ def prefixed_collapsible_map(m, prefix):
     if m == values.unset:
         return {}
 
-    def flatten_dict(d, result={}, prv_keys=[]):
+    def flatten_dict(d, result=None, prv_keys=None):
+
+        if result is None:
+            result = {}
+
+        if prv_keys is None:
+            prv_keys = []
+
         for k, v in d.items():
             if isinstance(v, dict):
                 flatten_dict(v, result, prv_keys + [k])

twilio/jwt/validation/__init__.py

@@ -72,13 +72,13 @@ def _generate_payload(self):
         }
 
     @classmethod
-    def _sort_and_join(self, values, joiner):
+    def _sort_and_join(cls, values, joiner):
         if isinstance(values, string_types):
             return values
         return joiner.join(sorted(values))
 
     @classmethod
-    def _hash(self, input_str):
+    def _hash(cls, input_str):
         if not input_str:
             return input_str
 

twilio/request_validator.py

@@ -52,7 +52,7 @@ def add_port(uri):
     """
     if uri.port:
         return uri.geturl()
-    
+
     port = 443 if uri.scheme == "https" else 80
     new_netloc = uri.netloc + ":" + str(port)
     new_uri = uri._replace(netloc=new_netloc)
@@ -75,7 +75,7 @@ def compute_signature(self, uri, params, utf=PY3):
         :returns: The computed signature
         """
         s = uri
-        if len(params) > 0:
+        if params:
             for k, v in sorted(params.items()):
                 s += k + v
 
@@ -117,7 +117,7 @@ def validate(self, uri, params, signature):
             valid_body_hash = compare(self.compute_hash(params), query["bodySHA256"][0])
             params = {}
 
-        #  check signature of uri with and without port, 
+        #  check signature of uri with and without port,
         #  since sig generation on back end is inconsistent
         valid_signature = compare(self.compute_signature(uri_without_port, params), signature)
         valid_signature_with_port = compare(self.compute_signature(uri_with_port, params), signature)