lint/stubgen: fix typing issues

src/capnp_stubgen/utils.py

@@ -1,6 +1,11 @@
 """Utility functions for capnp-stubgen."""
 
 import os
+from typing import Any
+
+#: A dict from capnp's ``CodeGeneratorRequest.to_dict()``.
+#: Keys are strings, values are arbitrary nested capnp data.
+NodeDict = dict[str, Any]
 
 
 def filename_to_module_name(filename: str) -> str:
@@ -14,18 +19,12 @@ def filename_to_module_name(filename: str) -> str:
     return base + "_capnp"
 
 
-def get_display_name(node: dict) -> str:
-    """Extract the short display name from a node dict.
-
-    The node's ``displayName`` field contains a path like
-    ``path/to/file.capnp:TypeName``. This removes the file prefix.
-    """
-    name: str = node["displayName"]
-    prefix_len: int = node["displayNamePrefixLength"]
-    return name[prefix_len:]
+def get_display_name(node: NodeDict) -> str:
+    """Extract the short display name from a node dict."""
+    return str(node["displayName"])[int(node["displayNamePrefixLength"]):]
 
 
-def get_node_kind(node: dict) -> str:
+def get_node_kind(node: NodeDict) -> str:
     """Determine the kind of a node from its dict representation.
 
     Returns one of: "file", "struct", "enum", "interface", "const", "annotation".