Make it possible to use dmypy (#9692)

Running `dmypy run` will do a `mypy` check while spinning up a daemon
that makes rerunning `dmypy run` a lot faster.

`dmypy` doesn't support `follow_imports = silent` and has
`local_partial_types` enabled, so this PR enables those options and
fixes the issues that were newly raised. Note that `local_partial_types`
will be enabled by default in upcoming mypy releases.

1 files changed, 1 insertions, 1 deletions

diff --git a/synapse/logging/opentracing.py b/synapse/logging/opentracing.py

index 10bd4a1461..c6e6335740 100644
--- a/synapse/logging/opentracing.py
+++ b/synapse/logging/opentracing.py
@@ -262,7 +262,7 @@ logger = logging.getLogger(__name__)
 # Block everything by default
 # A regex which matches the server_names to expose traces for.
 # None means 'block everything'.
-_homeserver_whitelist = None
+_homeserver_whitelist = None  # type: Optional[re.Pattern[str]]
 
 # Util methods