utils/modeling: support for annotations in python3.14

PEP 649 & PEP 749: Deferred evaluation of annotations
The annotations on classes(ConfigSchema classes in our case) are no longer evaluated eagerly.  They are evaluated only when necessary.

Author: alesmrazek

python/knot_resolver/utils/modeling/base_schema.py

@@ -12,6 +12,7 @@
 from .exceptions import AggregateDataValidationError, DataDescriptionError, DataValidationError
 from .renaming import Renamed, renamed
 from .types import (
+    get_annotations,
     get_generic_type_argument,
     get_generic_type_arguments,
     get_generic_type_wrapper_argument,
@@ -139,7 +140,8 @@ def _parse_attrs_docstrings(docstring: str) -> Optional[Dict[str, str]]:
 
 def _get_properties_schema(typ: Type[Any]) -> Dict[Any, Any]:
     schema: Dict[Any, Any] = {}
-    annot: Dict[str, Any] = typ.__dict__.get("__annotations__", {})
+    annot = get_annotations(typ)
+
     docstring: str = typ.__dict__.get("__doc__", "") or ""
     attribute_documentation = _parse_attrs_docstrings(docstring)
     for field_name, python_type in annot.items():
@@ -528,7 +530,7 @@ def _assign_fields(self, obj: Any, source: Union[Dict[str, Any], "BaseSchema", N
           2. assignments with conversion method
         """
         cls = obj.__class__
-        annot = cls.__dict__.get("__annotations__", {})
+        annot = get_annotations(cls)
         errs: List[DataValidationError] = []
 
         used_keys: Set[str] = set()
@@ -733,7 +735,7 @@ def __eq__(self, o: object) -> bool:
         if not isinstance(o, cls):
             return False
 
-        annot = cls.__dict__.get("__annotations__", {})
+        annot = get_annotations(cls)
         for name in annot.keys():
             if getattr(self, name) != getattr(o, name):
                 return False
@@ -775,7 +777,7 @@ def json_schema(
     def to_dict(self) -> Dict[Any, Any]:
         res: Dict[Any, Any] = {}
         cls = self.__class__
-        annot = cls.__dict__.get("__annotations__", {})
+        annot = get_annotations(cls)
 
         for name in annot:
             res[name] = Serializable.serialize(getattr(self, name))

python/knot_resolver/utils/modeling/types.py

@@ -11,6 +11,13 @@
 NoneType = type(None)
 
 
+def get_annotations(obj: Any) -> Dict[str, Any]:
+    if hasattr(inspect, "get_annotations"):
+        return inspect.get_annotations(obj)
+    # TODO(bump to py3.10): Safe to remove. This fallback exists for older versions
+    return obj.__dict__.get("__annotations__", {})
+
+
 def is_optional(tp: Any) -> bool:
     origin = getattr(tp, "__origin__", None)
     args = get_generic_type_arguments(tp)
@@ -83,7 +90,7 @@ def is_none_type(tp: Any) -> bool:
 def get_attr_type(obj: Any, attr_name: str) -> Any:
     assert hasattr(obj, attr_name)
     assert hasattr(obj, "__annotations__")
-    annot = getattr(type(obj), "__annotations__")
+    annot = get_annotations(type(obj))
     assert attr_name in annot
     return annot[attr_name]
 

tests/manager/datamodel/test_config_schema.py

@@ -6,6 +6,7 @@
 from knot_resolver.datamodel.lua_schema import LuaSchema
 from knot_resolver.utils.modeling import BaseSchema
 from knot_resolver.utils.modeling.types import (
+    get_annotations,
     get_generic_type_argument,
     get_generic_type_arguments,
     get_optional_inner_type,
@@ -37,7 +38,7 @@ def _check_str_type(cls: Type[Any], object_path: str = ""):
             _check_str_type(inner_type, object_path)
 
         elif inspect.isclass(cls) and issubclass(cls, BaseSchema):
-            annot = cls.__dict__.get("__annotations__", {})
+            annot = get_annotations(cls)
             for name, python_type in annot.items():
                 # ignore lua section
                 if python_type != LuaSchema: