Fix up some typechecking (#6150)

* type checking fixes

* changelog

synapse/logging/opentracing.py

@@ -170,6 +170,7 @@ import inspect
 import logging
 import re
 from functools import wraps
+from typing import Dict
 
 from canonicaljson import json
 
@@ -547,7 +548,7 @@ def inject_active_span_twisted_headers(headers, destination, check_destination=T
         return
 
     span = opentracing.tracer.active_span
-    carrier = {}
+    carrier = {}  # type: Dict[str, str]
     opentracing.tracer.inject(span, opentracing.Format.HTTP_HEADERS, carrier)
 
     for key, value in carrier.items():
@@ -584,7 +585,7 @@ def inject_active_span_byte_dict(headers, destination, check_destination=True):
 
     span = opentracing.tracer.active_span
 
-    carrier = {}
+    carrier = {}  # type: Dict[str, str]
     opentracing.tracer.inject(span, opentracing.Format.HTTP_HEADERS, carrier)
 
     for key, value in carrier.items():
@@ -639,7 +640,7 @@ def get_active_span_text_map(destination=None):
     if destination and not whitelisted_homeserver(destination):
         return {}
 
-    carrier = {}
+    carrier = {}  # type: Dict[str, str]
     opentracing.tracer.inject(
         opentracing.tracer.active_span, opentracing.Format.TEXT_MAP, carrier
     )
@@ -653,7 +654,7 @@ def active_span_context_as_string():
     Returns:
         The active span context encoded as a string.
     """
-    carrier = {}
+    carrier = {}  # type: Dict[str, str]
     if opentracing:
         opentracing.tracer.inject(
             opentracing.tracer.active_span, opentracing.Format.TEXT_MAP, carrier

synapse/logging/utils.py

@@ -119,7 +119,11 @@ def trace_function(f):
         logger = logging.getLogger(name)
         level = logging.DEBUG
 
-        s = inspect.currentframe().f_back
+        frame = inspect.currentframe()
+        if frame is None:
+            raise Exception("Can't get current frame!")
+
+        s = frame.f_back
 
         to_print = [
             "\t%s:%s %s. Args: args=%s, kwargs=%s"
@@ -144,7 +148,7 @@ def trace_function(f):
             pathname=pathname,
             lineno=lineno,
             msg=msg,
-            args=None,
+            args=tuple(),
             exc_info=None,
         )
 
@@ -157,7 +161,12 @@ def trace_function(f):
 
 
 def get_previous_frames():
-    s = inspect.currentframe().f_back.f_back
+
+    frame = inspect.currentframe()
+    if frame is None:
+        raise Exception("Can't get current frame!")
+
+    s = frame.f_back.f_back
     to_return = []
     while s:
         if s.f_globals["__name__"].startswith("synapse"):
@@ -174,7 +183,10 @@ def get_previous_frames():
 
 
 def get_previous_frame(ignore=[]):
-    s = inspect.currentframe().f_back.f_back
+    frame = inspect.currentframe()
+    if frame is None:
+        raise Exception("Can't get current frame!")
+    s = frame.f_back.f_back
 
     while s:
         if s.f_globals["__name__"].startswith("synapse"):