From 01b910a1480cb0b8094c87230b1ad91a0598ddd6 Mon Sep 17 00:00:00 2001
From: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
Date: Mon, 16 Oct 2023 16:31:16 -0700
Subject: [PATCH] bevy_reflect: Fix dynamic type serialization (#10103)

# Objective

Fixes #10086

## Solution

Instead of serializing via `DynamicTypePath::reflect_type_path`, now
uses the `TypePath` found on the `TypeInfo` returned by
`Reflect::get_represented_type_info`.

This issue was happening because the dynamic types implement `TypePath`
themselves and do not (and cannot) forward their proxy's `TypePath`
data. The solution was to access the proxy's type information in order
to get the correct `TypePath` data.

## Changed

- The `Debug` impl for `TypePathTable` now includes output for all
fields.
---
 crates/bevy_reflect/src/serde/mod.rs | 40 +++++++++++++++++++++++++---
 crates/bevy_reflect/src/serde/ser.rs | 17 +++++++++++-
 crates/bevy_reflect/src/type_path.rs |  4 +++
 3 files changed, 57 insertions(+), 4 deletions(-)

diff --git a/crates/bevy_reflect/src/serde/mod.rs b/crates/bevy_reflect/src/serde/mod.rs
index b675b5dcb2..5f87eba8f3 100644
--- a/crates/bevy_reflect/src/serde/mod.rs
+++ b/crates/bevy_reflect/src/serde/mod.rs
@@ -8,7 +8,7 @@ pub use type_data::*;
 
 #[cfg(test)]
 mod tests {
-    use crate::{self as bevy_reflect, DynamicTupleStruct};
+    use crate::{self as bevy_reflect, DynamicTupleStruct, Struct};
     use crate::{
         serde::{ReflectSerializer, UntypedReflectDeserializer},
         type_registry::TypeRegistry,
@@ -94,8 +94,10 @@ mod tests {
     }
 
     #[test]
-    #[should_panic(expected = "cannot get type info for bevy_reflect::DynamicStruct")]
-    fn unproxied_dynamic_should_not_serialize() {
+    #[should_panic(
+        expected = "cannot serialize dynamic value without represented type: bevy_reflect::DynamicStruct"
+    )]
+    fn should_not_serialize_unproxied_dynamic() {
         let registry = TypeRegistry::default();
 
         let mut value = DynamicStruct::default();
@@ -104,4 +106,36 @@ mod tests {
         let serializer = ReflectSerializer::new(&value, &registry);
         ron::ser::to_string(&serializer).unwrap();
     }
+
+    #[test]
+    fn should_roundtrip_proxied_dynamic() {
+        #[derive(Reflect)]
+        struct TestStruct {
+            a: i32,
+            b: i32,
+        }
+
+        let mut registry = TypeRegistry::default();
+        registry.register::<TestStruct>();
+
+        let value: DynamicStruct = TestStruct { a: 123, b: 456 }.clone_dynamic();
+
+        let serializer = ReflectSerializer::new(&value, &registry);
+
+        let expected = r#"{"bevy_reflect::serde::tests::TestStruct":(a:123,b:456)}"#;
+        let result = ron::ser::to_string(&serializer).unwrap();
+        assert_eq!(expected, result);
+
+        let mut deserializer = ron::de::Deserializer::from_str(&result).unwrap();
+        let reflect_deserializer = UntypedReflectDeserializer::new(&registry);
+
+        let expected = value.clone_value();
+        let result = reflect_deserializer
+            .deserialize(&mut deserializer)
+            .unwrap()
+            .take::<DynamicStruct>()
+            .unwrap();
+
+        assert!(expected.reflect_partial_eq(&result).unwrap());
+    }
 }
diff --git a/crates/bevy_reflect/src/serde/ser.rs b/crates/bevy_reflect/src/serde/ser.rs
index da0b464893..79ec73099a 100644
--- a/crates/bevy_reflect/src/serde/ser.rs
+++ b/crates/bevy_reflect/src/serde/ser.rs
@@ -68,7 +68,22 @@ impl<'a> Serialize for ReflectSerializer<'a> {
     {
         let mut state = serializer.serialize_map(Some(1))?;
         state.serialize_entry(
-            self.value.reflect_type_path(),
+            self.value
+                .get_represented_type_info()
+                .ok_or_else(|| {
+                    if self.value.is_dynamic() {
+                        Error::custom(format_args!(
+                            "cannot serialize dynamic value without represented type: {}",
+                            self.value.reflect_type_path()
+                        ))
+                    } else {
+                        Error::custom(format_args!(
+                            "cannot get type info for {}",
+                            self.value.reflect_type_path()
+                        ))
+                    }
+                })?
+                .type_path(),
             &TypedReflectSerializer::new(self.value, self.registry),
         )?;
         state.end()
diff --git a/crates/bevy_reflect/src/type_path.rs b/crates/bevy_reflect/src/type_path.rs
index 9861f76289..99f9b81e6e 100644
--- a/crates/bevy_reflect/src/type_path.rs
+++ b/crates/bevy_reflect/src/type_path.rs
@@ -183,6 +183,10 @@ impl fmt::Debug for TypePathTable {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_struct("TypePathVtable")
             .field("type_path", &self.type_path)
+            .field("short_type_path", &(self.short_type_path)())
+            .field("type_ident", &(self.type_ident)())
+            .field("crate_name", &(self.crate_name)())
+            .field("module_path", &(self.module_path)())
             .finish()
     }
 }