Improve error when accessing unsupported mapping

src/ansys/acp/core/_server/direct.py

@@ -22,6 +22,7 @@
 
 import dataclasses
 import os
+import pathlib
 import subprocess
 from typing import TextIO
 
@@ -103,6 +104,10 @@ def start(self) -> None:
         stdout_file = self._config.stdout_file
         stderr_file = self._config.stderr_file
 
+        binary = pathlib.Path(self._config.binary_path)
+        if not binary.exists():
+            raise FileNotFoundError(f"Binary not found: '{binary}'")
+
         port = find_free_ports()[0]
         self._url = f"localhost:{port}"
         self._stdout = open(stdout_file, mode="w", encoding="utf-8")

src/ansys/acp/core/_tree_objects/_grpc_helpers/mapping.py

@@ -26,6 +26,7 @@
 from typing import Any, Concatenate, Generic, TypeVar
 
 from grpc import Channel
+from packaging.version import parse as parse_version
 from typing_extensions import ParamSpec, Self
 
 from ansys.api.acp.v0.base_pb2 import CollectionPath, DeleteRequest, ListRequest
@@ -302,6 +303,14 @@ def define_mutable_mapping(
     """Define a mutable mapping of child tree objects."""
 
     def collection_property(self: ParentT) -> MutableMapping[CreatableValueT]:
+        if object_class._SUPPORTED_SINCE is not None and self._server_version is not None:
+            if self._server_version < parse_version(object_class._SUPPORTED_SINCE):
+                raise RuntimeError(
+                    f"The '{object_class.__name__}' object is only supported since version "
+                    f"{object_class._SUPPORTED_SINCE} of the ACP gRPC server. The current server version is "
+                    f"{self._server_version}."
+                )
+
         return MutableMapping._initialize_with_cache(
             server_wrapper=self._server_wrapper,
             collection_path=CollectionPath(