Refactor PvaDictConverter to be less PVI specific

src/ophyd_async/epics/_backend/_p4p.py

@@ -141,14 +141,13 @@ def descriptor(self, source: str, value) -> Descriptor:
         return dict(source=source, dtype="object", shape=[])  # type: ignore
 
 
-class PvaStructureConverter(PvaConverter):
+class PvaDictConverter(PvaConverter):
 
     def value(self, value):
-        return value.get("pvi")
+        return value
 
     def descriptor(self, source: str, value) -> Descriptor:
-        # This is wrong, but defer until we know how to actually describe a structure
-        return dict(source=source, dtype="object", shape=[])  # type: ignore
+        raise NotImplementedError("Describing Dict signals not currently supported")
 
 
 class DisconnectedPvaConverter(PvaConverter):
@@ -216,7 +215,7 @@ def make_converter(datatype: Optional[Type], values: Dict[str, Any]) -> PvaConve
     elif "NTTable" in typeid:
         return PvaTableConverter()
     elif "structure" in typeid:
-        return PvaStructureConverter()
+        return PvaDictConverter()
     else:
         raise TypeError(f"{pv}: Unsupported typeid {typeid}")
 

src/ophyd_async/epics/pvi.py

@@ -45,8 +45,8 @@ async def pvi_get(
     timeout, and therefore can be used for error reporting."""
     backend: SignalBackend = PvaSignalBackend(None, read_pv, read_pv)
     await backend.connect(timeout=timeout)
-    pv_info: Dict[str, Dict[str, str]] = await backend.get_value()
-
+    d: Dict[str, Dict[str, Dict[str, str]]] = await backend.get_value()
+    pv_info = d.get("pvi") or {}
     result = {}
 
     for attr_name, attr_info in pv_info.items():