fix(android): guard stale layer remove path (#4300)

Co-authored-by: Cursor <cursoragent@cursor.com>

platform/android/MapLibreAndroid/src/cpp/native_map_view.cpp

@@ -1154,11 +1154,20 @@ jni::jboolean NativeMapView::removeLayerAt(JNIEnv& env, jni::jint index) {
 /**
  * Remove with wrapper object id. Ownership is transferred back to the wrapper
  */
-jni::jboolean NativeMapView::removeLayer(JNIEnv&, jlong layerPtr) {
-    assert(layerPtr != 0);
+jni::jboolean NativeMapView::removeLayer(JNIEnv& env, jlong layerPtr) {
+    if (layerPtr == 0) {
+        Log::Warning(Event::JNI, "Cannot remove layer: native layer pointer is null");
+        return jni::jni_false;
+    }
 
     mbgl::android::Layer* layer = reinterpret_cast<mbgl::android::Layer*>(layerPtr);
-    std::unique_ptr<mbgl::style::Layer> coreLayer = map->getStyle().removeLayer(layer->get().getID());
+    const auto layerId = jni::Make<std::string>(env, layer->getId(env));
+    if (layerId.empty()) {
+        Log::Warning(Event::JNI, "Cannot remove layer: layer reference is detached or invalid");
+        return jni::jni_false;
+    }
+
+    std::unique_ptr<mbgl::style::Layer> coreLayer = map->getStyle().removeLayer(layerId);
     if (coreLayer) {
         layer->setLayer(std::move(coreLayer));
         return jni::jni_true;

platform/android/MapLibreAndroid/src/main/java/org/maplibre/android/maps/NativeMapView.java

@@ -1000,7 +1000,17 @@ final class NativeMapView implements NativeMap {
     if (checkState("removeLayer")) {
       return false;
     }
-    return nativeRemoveLayer(layer.getNativePtr());
+    if (layer.isDetached()) {
+      Logger.w(TAG, "Ignoring removeLayer() call on detached layer reference.");
+      return false;
+    }
+
+    final long nativePtr = layer.getNativePtr();
+    if (nativePtr == 0L) {
+      Logger.w(TAG, "Ignoring removeLayer() call on released layer pointer.");
+      return false;
+    }
+    return nativeRemoveLayer(nativePtr);
   }
 
   @Override

platform/android/MapLibreAndroidTestApp/src/androidTest/java/org/maplibre/android/testapp/style/RuntimeStyleTests.java

@@ -9,6 +9,7 @@ import androidx.test.espresso.ViewAction;
 import androidx.test.internal.runner.junit4.AndroidJUnit4ClassRunner;
 
 import org.maplibre.android.style.layers.CannotAddLayerException;
+import org.maplibre.android.style.layers.BackgroundLayer;
 import org.maplibre.android.style.layers.CircleLayer;
 import org.maplibre.android.style.layers.FillLayer;
 import org.maplibre.android.style.layers.Layer;
@@ -22,6 +23,7 @@ import org.maplibre.android.style.sources.Source;
 import org.maplibre.android.style.sources.VectorSource;
 import org.maplibre.android.testapp.R;
 import org.maplibre.android.testapp.activity.EspressoTest;
+import org.maplibre.android.maps.Style;
 
 import org.hamcrest.Matcher;
 import org.junit.Assert;
@@ -300,6 +302,53 @@ public class RuntimeStyleTests extends EspressoTest {
     });
   }
 
+  @Test
+  public void testRemoveStaleLayerReferenceDoesNotCrash() {
+    validateTestSetup();
+    onView(withId(R.id.mapView)).perform(new BaseViewAction() {
+      @Override
+      public void perform(UiController uiController, View view) {
+        final Layer[] staleLayerHolder = new Layer[1];
+        final Throwable[] errorHolder = new Throwable[1];
+        final Boolean[] removeResultHolder = new Boolean[1];
+        final boolean[] finished = new boolean[] { false };
+
+        Style.Builder styleABuilder = new Style.Builder()
+            .withLayer(new BackgroundLayer("stale-layer-a")
+                .withProperties(PropertyFactory.backgroundColor(Color.BLUE)));
+        Style.Builder styleBBuilder = new Style.Builder()
+            .withLayer(new BackgroundLayer("style-b-background")
+                .withProperties(PropertyFactory.backgroundColor(Color.DKGRAY)));
+
+        maplibreMap.setStyle(styleABuilder, styleA -> {
+          staleLayerHolder[0] = styleA.getLayer("stale-layer-a");
+
+          maplibreMap.setStyle(styleBBuilder, styleB -> {
+            try {
+              removeResultHolder[0] = styleB.removeLayer(staleLayerHolder[0]);
+            } catch (Throwable error) {
+              errorHolder[0] = error;
+            } finally {
+              finished[0] = true;
+            }
+          });
+        });
+
+        long timeoutMs = 5000;
+        long startMs = System.currentTimeMillis();
+        while (!finished[0] && System.currentTimeMillis() - startMs < timeoutMs) {
+          uiController.loopMainThreadForAtLeast(50);
+        }
+
+        assertTrue("Style switch did not finish in time", finished[0]);
+        assertNotNull("Stale layer should have been captured", staleLayerHolder[0]);
+        assertNull("Removing stale layer reference should not throw", errorHolder[0]);
+        assertFalse("Removing stale layer reference should fail gracefully",
+            Boolean.TRUE.equals(removeResultHolder[0]));
+      }
+    });
+  }
+
   /**
    * https://github.com/mapbox/mapbox-gl-native/issues/7973
    */