From c6e3a1773703d4f8b42f001e1b506b012f6c12c1 Mon Sep 17 00:00:00 2001
From: Minsik Kim <kmsbernard@gmail.com>
Date: Wed, 25 Feb 2026 17:29:15 +0900
Subject: [PATCH 1/2] [Android][NativeAnimated] Add regression test for
 detached tracking spring toValue

---
 .../NativeAnimatedNodeTraversalTest.kt        | 38 +++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/packages/react-native/ReactAndroid/src/test/java/com/facebook/react/animated/NativeAnimatedNodeTraversalTest.kt b/packages/react-native/ReactAndroid/src/test/java/com/facebook/react/animated/NativeAnimatedNodeTraversalTest.kt
index dfb2afefec9a..c4f6eac45c79 100644
--- a/packages/react-native/ReactAndroid/src/test/java/com/facebook/react/animated/NativeAnimatedNodeTraversalTest.kt
+++ b/packages/react-native/ReactAndroid/src/test/java/com/facebook/react/animated/NativeAnimatedNodeTraversalTest.kt
@@ -1370,6 +1370,44 @@ class NativeAnimatedNodeTraversalTest {
     assertThat(previousValue).isEqualTo(1.5)
   }
 
+  @Test
+  fun testTrackingSpringDoesNotCrashWhenToValueNodeIsDetached() {
+    val springConfig: JavaOnlyMap =
+        JavaOnlyMap.of(
+            "type",
+            "spring",
+            "stiffness",
+            230.2,
+            "damping",
+            22.0,
+            "mass",
+            1.0,
+            "initialVelocity",
+            0.0,
+            "restSpeedThreshold",
+            0.001,
+            "restDisplacementThreshold",
+            0.001,
+            "overshootClamping",
+            false,
+        )
+
+    createAnimatedGraphWithTrackingNode(springConfig)
+
+    nativeAnimatedNodesManager.setAnimatedNodeValue(1, 1.0)
+    nativeAnimatedNodesManager.runUpdates(nextFrameTime())
+
+    nativeAnimatedNodesManager.disconnectAnimatedNodes(1, 2)
+    nativeAnimatedNodesManager.dropAnimatedNode(1)
+
+    nativeAnimatedNodesManager.runUpdates(nextFrameTime())
+
+    val trackedNode = nativeAnimatedNodesManager.getNodeById(3) as? ValueAnimatedNode
+    assertThat(trackedNode).isNotNull
+    val trackedValue = checkNotNull(trackedNode).getValue()
+    assertThat(trackedValue.isNaN()).isFalse
+  }
+
   companion object {
     private const val FRAME_LEN_NANOS: Long = 1000000000L / 60L
     private const val INITIAL_FRAME_TIME_NANOS: Long = 14599233201256L /* random */

From 2579213e080711b6f34b1046302f88c0deceb892 Mon Sep 17 00:00:00 2001
From: Minsik Kim <kmsbernard@gmail.com>
Date: Wed, 25 Feb 2026 17:29:20 +0900
Subject: [PATCH 2/2] [Android][NativeAnimated] Guard tracking spring when
 toValue node is detached

---
 .../com/facebook/react/animated/TrackingAnimatedNode.kt     | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/animated/TrackingAnimatedNode.kt b/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/animated/TrackingAnimatedNode.kt
index 1a355743fda7..dbc491a10b3b 100644
--- a/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/animated/TrackingAnimatedNode.kt
+++ b/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/animated/TrackingAnimatedNode.kt
@@ -25,7 +25,11 @@ internal class TrackingAnimatedNode(
     if (valAnimatedNode != null) {
       animationConfig.putDouble("toValue", valAnimatedNode.getValue())
     } else {
-      animationConfig.putNull("toValue")
+      val drivenNode = nativeAnimatedNodesManager.getNodeById(valueNode) as? ValueAnimatedNode
+      if (drivenNode == null) {
+        return
+      }
+      animationConfig.putDouble("toValue", drivenNode.getValue())
     }
     nativeAnimatedNodesManager.startAnimatingNode(animationId, valueNode, animationConfig, null)
   }