Add capnp Visibility::Unspecified to fix remaining tests

Author: acl-cqc

hugr-model/capnp/hugr-v0.capnp

@@ -123,6 +123,7 @@ struct Param {
 }
 
 enum Visibility {
-    private @0;
-    public @1;
+    unspecified @0;
+    private @1;
+    public @2;
 }

hugr-model/src/capnp/hugr_v0_capnp.rs

@@ -190,11 +190,12 @@ fn read_region_scope(reader: hugr_capnp::region_scope::Reader) -> ReadResult<tab
     Ok(table::RegionScope { links, ports })
 }
 
-impl From<hugr_capnp::Visibility> for model::Visibility {
+impl From<hugr_capnp::Visibility> for Option<model::Visibility> {
     fn from(value: hugr_capnp::Visibility) -> Self {
         match value {
-            hugr_capnp::Visibility::Private => model::Visibility::Private,
-            hugr_capnp::Visibility::Public => model::Visibility::Public,
+            hugr_capnp::Visibility::Unspecified => None,
+            hugr_capnp::Visibility::Private => Some(model::Visibility::Private),
+            hugr_capnp::Visibility::Public => Some(model::Visibility::Public),
         }
     }
 }
@@ -206,7 +207,7 @@ fn read_symbol<'a>(
     constraints: Option<&'a [table::TermId]>,
 ) -> ReadResult<&'a mut table::Symbol<'a>> {
     let name = bump.alloc_str(reader.get_name()?.to_str()?);
-    let visibility = reader.get_visibility().map(model::Visibility::from).ok();
+    let visibility = reader.get_visibility()?.into();
     let visibility = bump.alloc(visibility);
     let params = read_list!(bump, reader.get_params()?, read_param);
     let constraints = match constraints {

hugr-model/src/v0/binary/read.rs

@@ -115,7 +115,7 @@ fn write_symbol(mut builder: hugr_capnp::symbol::Builder, symbol: &table::Symbol
             model::Visibility::Private => hugr_capnp::Visibility::Private,
             model::Visibility::Public => hugr_capnp::Visibility::Public,
         })
-    }
+    } // else, None -> use capnp default == Unspecified
     write_list!(builder, init_params, write_param, symbol.params);
     let _ = builder.set_constraints(table::TermId::unwrap_slice(symbol.constraints));
     builder.set_signature(symbol.signature.0);