Patch type checking issues (#572)

These are issues with typeshed and some interpretation of
`type[...]`. There aren't relevant runtime tweaks to apply, just notes
on why these items are ignored.

Author: sirosen

src/check_jsonschema/formats/__init__.py

@@ -50,11 +50,16 @@ def __init__(
 
 
 def get_base_format_checker(schema_dialect: str | None) -> jsonschema.FormatChecker:
+    # mypy does not consider a class whose instances match a protocol to match
+    # `type[$PROTOCOL]` so this is considered a mismatch
+    default_validator_cls: type[jsonschema.Validator] = (
+        jsonschema.Draft202012Validator  # type:ignore[assignment]
+    )
     # resolve the dialect, if given, to a validator class
     # default to the latest draft
     validator_class = jsonschema.validators.validator_for(
         {} if schema_dialect is None else {"$schema": schema_dialect},
-        default=jsonschema.Draft202012Validator,
+        default=default_validator_cls,
     )
     return validator_class.FORMAT_CHECKER
 

src/check_jsonschema/schema_loader/main.py

@@ -187,7 +187,11 @@ def _get_validator(
         validator_cls = _extend_with_pattern_implementation(validator_cls, regex_impl)
 
         # now that we know it's safe to try to create the validator instance, do it
-        validator = validator_cls(
+        #
+        # TODO: remove type ignore
+        #       mypy flags this because of an incorrect signature in typeshed
+        #       see: https://github.com/python/typeshed/pull/14327
+        validator = validator_cls(  # type: ignore[call-arg]
             schema,
             registry=reference_registry,
             format_checker=format_checker,