feat: add backend property to RiveFileFactory for runtime detection

Author: mfazekas

android/src/experimental/java/com/margelo/nitro/rive/HybridRiveFileFactory.kt

@@ -61,6 +61,8 @@ object RiveErrorLogger : app.rive.RiveLog.Logger {
 @Keep
 @DoNotStrip
 class HybridRiveFileFactory : HybridRiveFileFactorySpec() {
+  override val backend: String = "experimental"
+
   companion object {
     private const val TAG = "HybridRiveFileFactory"
 

android/src/legacy/java/com/margelo/nitro/rive/HybridRiveFileFactory.kt

@@ -20,6 +20,8 @@ data class FileAndCache(
 @Keep
 @DoNotStrip
 class HybridRiveFileFactory : HybridRiveFileFactorySpec() {
+  override val backend: String = "legacy"
+
   private fun buildRiveFile(
     data: ByteArray,
     referencedAssets: ReferencedAssetsType?

example/__tests__/viewmodel-properties.harness.ts

@@ -29,6 +29,12 @@ function getRGB(color: number): { r: number; g: number; b: number } {
 /* eslint-enable no-bitwise */
 
 describe('ViewModel Properties', () => {
+  it('backend property is accessible', () => {
+    const backend = RiveFileFactory.getBackend();
+    expect(typeof backend).toBe('string');
+    expect(['legacy', 'experimental']).toContain(backend);
+  });
+
   it('numberProperty get/set works', async () => {
     const instance = await createGordonInstance();
     const ageProperty = instance.numberProperty('age');
@@ -176,6 +182,11 @@ describe('Property Listeners', () => {
   });
 
   it('colorProperty addListener returns cleanup function', async () => {
+    if (Platform.OS === 'ios' && RiveFileFactory.getBackend() === 'experimental') {
+      // rive-ios experimental: Color.argbValue is internal, addListener not supported
+      return;
+    }
+
     const instance = await createGordonInstance();
     const prop = instance.colorProperty('favourite_color');
     expectDefined(prop);

ios/legacy/HybridRiveFileFactory.swift

@@ -2,6 +2,8 @@ import NitroModules
 import RiveRuntime
 
 final class HybridRiveFileFactory: HybridRiveFileFactorySpec, @unchecked Sendable {
+  var backend: String { "legacy" }
+
   let assetLoader = ReferencedAssetLoader()
 
   /// Asynchronously creates a `HybridRiveFileSpec` by performing the following steps:

ios/new/HybridRiveFileFactory.swift

@@ -2,6 +2,7 @@
 import NitroModules
 
 final class HybridRiveFileFactory: HybridRiveFileFactorySpec, @unchecked Sendable {
+  var backend: String { "experimental" }
 
   // All files must share the same Worker so artboard handles are valid across files
   // (each Worker has its own C++ command server with its own m_artboards map)