diff --git a/scripts-dev/mypy_synapse_plugin.py b/scripts-dev/mypy_synapse_plugin.py
index c775865212..d08517a953 100644
--- a/scripts-dev/mypy_synapse_plugin.py
+++ b/scripts-dev/mypy_synapse_plugin.py
@@ -21,7 +21,7 @@ from typing import Callable, Optional, Type
from mypy.nodes import ARG_NAMED_OPT
from mypy.plugin import MethodSigContext, Plugin
from mypy.typeops import bind_self
-from mypy.types import CallableType, NoneType
+from mypy.types import CallableType, NoneType, UnionType
class SynapsePlugin(Plugin):
@@ -72,13 +72,20 @@ def cached_function_method_signature(ctx: MethodSigContext) -> CallableType:
# Third, we add an optional "on_invalidate" argument.
#
- # This is a callable which accepts no input and returns nothing.
- calltyp = CallableType(
- arg_types=[],
- arg_kinds=[],
- arg_names=[],
- ret_type=NoneType(),
- fallback=ctx.api.named_generic_type("builtins.function", []),
+ # This is a either
+ # - a callable which accepts no input and returns nothing, or
+ # - None.
+ calltyp = UnionType(
+ [
+ NoneType(),
+ CallableType(
+ arg_types=[],
+ arg_kinds=[],
+ arg_names=[],
+ ret_type=NoneType(),
+ fallback=ctx.api.named_generic_type("builtins.function", []),
+ ),
+ ]
)
arg_types.append(calltyp)
@@ -95,7 +102,7 @@ def cached_function_method_signature(ctx: MethodSigContext) -> CallableType:
def plugin(version: str) -> Type[SynapsePlugin]:
- # This is the entry point of the plugin, and let's us deal with the fact
+ # This is the entry point of the plugin, and lets us deal with the fact
# that the mypy plugin interface is *not* stable by looking at the version
# string.
#
|
