Traverse inheritance tree to find defaults in rbx_binary serializer (#…

…420)
rojo-rbx · Jul 20, 2024 · 944e747 · 944e747
1 parent 3f689f5
commit 944e747
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Showing 3 changed files with 25 additions and 3 deletions.
diff --git a/rbx_binary/src/serializer/state.rs b/rbx_binary/src/serializer/state.rs
@@ -397,9 +397,8 @@ impl<'dom, 'db, W: Write> SerializerState<'dom, 'db, W> {
                 let default_value = type_info
                     .class_descriptor
                     .and_then(|class| {
-                        class
-                            .default_properties
-                            .get(&canonical_name)
+                        database
+                            .find_default_property(class, &canonical_name)
                             .map(Cow::Borrowed)
                     })
                     .or_else(|| Self::fallback_default_value(serialized_ty).map(Cow::Owned))

diff --git a/rbx_reflection/CHANGELOG.md b/rbx_reflection/CHANGELOG.md
@@ -2,8 +2,10 @@
 
 ## Unreleased Changes
 * Add `superclasses` method to `ReflectionDatabase` to get a set of superclasses for a given class. ([#402])
+* Added method `ReflectionDatabase::find_default_property`, which finds the default value of a property given its name and a class that inherits it. ([#420])
 
 [#402]: https://github.com/rojo-rbx/rbx-dom/pull/402
+[#420]: https://github.com/rojo-rbx/rbx-dom/pull/420
 
 ## 4.5.0 (2024-01-16)
 * Update to rbx_types 1.8.

diff --git a/rbx_reflection/src/database.rs b/rbx_reflection/src/database.rs
@@ -57,6 +57,27 @@ impl<'a> ReflectionDatabase<'a> {
 
         Some(list)
     }
+
+    /// Finds the default value of a property given its name and a class that
+    /// contains or inherits the property. Returns `Some(&Variant)` if a default
+    /// value exists, None otherwise.
+    pub fn find_default_property(
+        &'a self,
+        mut class: &'a ClassDescriptor<'a>,
+        property_name: &str,
+    ) -> Option<&'a Variant> {
+        loop {
+            match class.default_properties.get(property_name) {
+                None => {
+                    class = self
+                        .classes
+                        .get(class.superclass.as_ref()?)
+                        .expect("superclass that is Some should exist in reflection database")
+                }
+                default_value => return default_value,
+            }
+        }
+    }
 }
 
 /// Describes a class of Instance, its properties, and its relation to other