persist/util: add field helper

pkgs/clan-cli/clan_lib/persist/util.py

@@ -452,3 +452,39 @@ def set_value_by_path(d: DictLike, path: str, content: Any) -> None:
     for key in keys[:-1]:
         current = current.setdefault(key, {})
     current[keys[-1]] = content
+
+
+from typing import NotRequired, Required, get_args, get_origin, get_type_hints
+
+
+def is_typeddict_class(obj: type) -> bool:
+    """Safely checks if a class is a TypedDict."""
+    return (
+        isinstance(obj, type)
+        and hasattr(obj, "__annotations__")
+        and obj.__class__.__name__ == "_TypedDictMeta"
+    )
+
+
+def retrieve_typed_field_names(obj: type, prefix: str = "") -> set[str]:
+    fields = set()
+    hints = get_type_hints(obj, include_extras=True)
+
+    for field, field_type in hints.items():
+        full_key = f"{prefix}.{field}" if prefix else field
+
+        origin = get_origin(field_type)
+        args = get_args(field_type)
+
+        # Unwrap Required/NotRequired
+        if origin in {NotRequired, Required}:
+            field_type = args[0]
+            origin = get_origin(field_type)
+            args = get_args(field_type)
+
+        if is_typeddict_class(field_type):
+            fields |= retrieve_typed_field_names(field_type, prefix=full_key)
+        else:
+            fields.add(full_key)
+
+    return fields