Create objects for delegating components

crates/re_types_builder/src/codegen/python.rs

@@ -277,7 +277,7 @@ impl PythonCodeGenerator {
                     let name = &obj.name;
 
                     if obj.is_delegating_component() {
-                        vec![format!("{name}Array"), format!("{name}Type")]
+                        vec![name.clone(), format!("{name}Array"), format!("{name}Type")]
                     } else {
                         vec![
                             format!("{name}"),
@@ -516,10 +516,11 @@ fn code_for_struct(
 
     let mut code = String::new();
 
-    if *kind != ObjectKind::Component || obj.is_non_delegating_component() {
     // field converters preprocessing pass — must be performed here because we must autogen
     // converter function *before* the class
     let mut field_converters: HashMap<String, String> = HashMap::new();
+
+    if !obj.is_delegating_component() {
         for field in fields {
             let (default_converter, converter_function) =
                 quote_field_converter_from_field(obj, objects, field);
@@ -552,6 +553,7 @@ fn code_for_struct(
             };
             field_converters.insert(field.fqname.clone(), converter);
         }
+    }
 
     // If the `ExtensionClass` has its own `__init__` then we need to pass the `init=False` argument
     // to the `@define` decorator, to prevent it from generating its own `__init__`, which would
@@ -566,11 +568,20 @@ fn code_for_struct(
     let mut superclasses = vec![];
 
     if *kind == ObjectKind::Archetype {
-            superclasses.push("Archetype");
+        superclasses.push("Archetype".to_owned());
     }
 
     if ext_class.found {
-            superclasses.push(ext_class.name.as_str());
+        superclasses.push(ext_class.name.clone());
+    }
+
+    // Delegating component inheritance comes after the `ExtensionClass`
+    // This way if a component needs to override `__init__` it still can.
+    if obj.is_delegating_component() {
+        superclasses.push(format!(
+            "datatypes.{}",
+            obj.delegate_datatype(objects).unwrap().name
+        ));
     }
 
     let superclass_decl = if superclasses.is_empty() {
@@ -594,10 +605,16 @@ fn code_for_struct(
         format!("({define_args})")
     };
 
+    let define_decorator = if obj.is_delegating_component() {
+        String::new()
+    } else {
+        format!("@define{define_args}")
+    };
+
     code.push_unindented_text(
         format!(
             r#"
-                @define{define_args}
+                {define_decorator}
                 class {name}{superclass_decl}:
                 "#
         ),
@@ -634,6 +651,18 @@ fn code_for_struct(
         );
     }
 
+    if obj.is_delegating_component() {
+        code.push_text(
+            format!(
+                "# Note: there are no fields here because {} delegates to datatypes.{}",
+                obj.name,
+                obj.delegate_datatype(objects).unwrap().name
+            ),
+            1,
+            4,
+        );
+        code.push_text("pass", 2, 4);
+    } else {
         // NOTE: We need to add required fields first, and then optional ones, otherwise mypy
         // complains.
         // TODO(ab, #2641): this is required because fields without default should appear before fields