diff --git a/changelog.d/12873.misc b/changelog.d/12873.misc
new file mode 100644
index 0000000000..c441084264
--- /dev/null
+++ b/changelog.d/12873.misc
@@ -0,0 +1 @@
+Add stricter JSON type annotations to the Module API's account data manager.
\ No newline at end of file
diff --git a/synapse/types.py b/synapse/types.py
index 6f7128ddd6..7200dedf5f 100644
--- a/synapse/types.py
+++ b/synapse/types.py
@@ -26,6 +26,7 @@ from typing import (
MutableMapping,
NoReturn,
Optional,
+ Protocol,
Set,
Tuple,
Type,
@@ -77,6 +78,46 @@ JsonMapping = Mapping[str, Any]
JsonSerializable = object
+if TYPE_CHECKING:
+ # This is a very hacky way to have a strongly-typed JSON object
+ # that doesn't stop short at Dict[str, Any].
+ # https://github.com/python/typing/issues/182#issuecomment-899624078
+
+ StrictJson = ...
+
+ class StrictJsonArray(List[StrictJson], Protocol): # type: ignore
+ __class__: Type[List[StrictJson]] # type: ignore
+
+ class StrictJsonDict(Dict[str, StrictJson], Protocol): # type: ignore
+ __class__: Type[Dict[str, StrictJson]] # type: ignore
+
+ StrictJson = Union[None, float, str, StrictJsonArray, StrictJsonDict] # type: ignore[assignment]
+else:
+ # We need some types for runtime.
+ StrictJson = Union[None, float, str, List[Any], Dict[str, Any]]
+ StrictJsonDict = Dict[str, StrictJson]
+
+
+if TYPE_CHECKING:
+ # Analogous to StrictJson, this is a version that uses entirely frozen data.
+
+ StrictFrozenJson = ...
+
+ class StrictFrozenJsonArray(Tuple[StrictFrozenJson, ...], Protocol): # type: ignore
+ __class__: Type[Tuple[StrictFrozenJson, ...]] # type: ignore
+
+ class StrictFrozenJsonDict(frozendict[str, StrictFrozenJson], Protocol): # type: ignore
+ __class__: Type[frozendict[str, StrictFrozenJson]] # type: ignore
+
+ StrictFrozenJson = Union[ # type: ignore[assignment]
+ None, float, str, StrictFrozenJsonArray, StrictFrozenJsonDict
+ ]
+else:
+ # We need some types for runtime.
+ StrictFrozenJson = Union[None, float, str, Tuple[Any, ...], frozendict[str, Any]]
+ StrictFrozenJsonDict = frozendict[str, StrictFrozenJson]
+
+
# Note that this seems to require inheriting *directly* from Interface in order
# for mypy-zope to realize it is an interface.
class ISynapseReactor(
|
