Document limitation on output struct member handles and add check for it

Author: aarongreig

scripts/core/CONTRIB.rst

@@ -226,6 +226,8 @@ following:
   ``[optional]`` tag if that struct (or any of its members, recursively) has
   an object handle member in its definition.
 
+* A struct member which is an object handle must not have the ``[out]`` tag.
+
 Forks and Pull Requests
 =======================
 

scripts/parse_specs.py

@@ -327,6 +327,9 @@ def __validate_members(d, tags, meta):
                 __validate_struct_range_members(item['name'], member_members,
                                                 meta)
 
+            if type_traits.is_handle(item['type']) and param_traits.is_output(item):
+                raise Exception(prefix + f"struct member {item['name']} is an object handle, so it must not be have the [out] tag")
+
             ver = __validate_version(item, prefix=prefix, base_version=d_ver)
             if ver < max_ver:
                 raise Exception(prefix+"'version' must be increasing: %s"%item['version'])

scripts/templates/ldrddi.cpp.mako

@@ -175,7 +175,8 @@ namespace ur_loader
             size_t sizeret = 0;
             if (pPropSizeRet == NULL)
                 pPropSizeRet = &sizeret;
-        
+        %endif
+
         ## Here we deal with handles buried inside struct type parameters. First
         ## we create a local copy of the struct, then we convert all the handles
         ## in that local copy and set the parameter to point to it before forwarding