WIP: Fix ANR caused by operationRepo.enqueue while loading is in progress

OneSignalSDK/onesignal/core/src/main/java/com/onesignal/common/modeling/ModelStore.kt

@@ -169,33 +169,34 @@ abstract class ModelStore<TModel>(
 
         val str = _prefs.getString(PreferenceStores.ONESIGNAL, PreferenceOneSignalKeys.MODEL_STORE_PREFIX + name, "[]")
         val jsonArray = JSONArray(str)
-        synchronized(models) {
-            val shouldRePersist = models.isNotEmpty()
-            for (index in jsonArray.length() - 1 downTo 0) {
-                val newModel = create(jsonArray.getJSONObject(index)) ?: continue
-
-                /*
-                 * NOTE: Migration fix for bug introduced in 5.1.12
-                 * The following check is intended for the operation model store.
-                 * When the call to this method moved out of the operation model store's initializer,
-                 * duplicate operations could be cached.
-                 * See https://github.com/OneSignal/OneSignal-Android-SDK/pull/2099
-                 */
-                val hasExisting = models.any { it.id == newModel.id }
-                if (hasExisting) {
-                    Logging.debug("ModelStore<$name>: load - operation.id: ${newModel.id} already exists in the store.")
-                    continue
-                }
 
-                models.add(0, newModel)
-                // listen for changes to this model
-                newModel.subscribe(this)
+        val shouldRePersist = models.isNotEmpty()
+        for (index in jsonArray.length() - 1 downTo 0) {
+            val newModel = create(jsonArray.getJSONObject(index)) ?: continue
+
+            /*
+             * NOTE: Migration fix for bug introduced in 5.1.12
+             * The following check is intended for the operation model store.
+             * When the call to this method moved out of the operation model store's initializer,
+             * duplicate operations could be cached.
+             * See https://github.com/OneSignal/OneSignal-Android-SDK/pull/2099
+             */
+            val hasExisting = models.any { it.id == newModel.id }
+            if (hasExisting) {
+                Logging.debug("ModelStore<$name>: load - operation.id: ${newModel.id} already exists in the store.")
+                continue
             }
-            hasLoadedFromCache = true
-            // optimization only: to avoid unnecessary writes
-            if (shouldRePersist) {
-                persist()
+
+            synchronized(models) {
+                models.add(0, newModel)
             }
+            // listen for changes to this model
+            newModel.subscribe(this)
+        }
+        hasLoadedFromCache = true
+        // optimization only: to avoid unnecessary writes
+        if (shouldRePersist) {
+            persist()
         }
     }
 

OneSignalSDK/onesignal/core/src/test/java/com/onesignal/common/ModelingTests.kt

@@ -20,6 +20,41 @@ import java.util.UUID
 
 class ModelingTests : FunSpec({
 
+    test("ensure prolonged loading in the background thread does not block insertion in the main thread") {
+        // Given
+        val prefs = MockPreferencesService()
+        val operationModelStore = OperationModelStore(prefs)
+
+        // add an arbitrary operation to the cache
+        val cachedOperation = LoginUserFromSubscriptionOperation()
+        val newOperation = LoginUserOperation()
+        cachedOperation.id = UUID.randomUUID().toString()
+        val jsonArray = JSONArray()
+        jsonArray.put(cachedOperation.toJSON())
+        prefs.saveString(PreferenceStores.ONESIGNAL, PreferenceOneSignalKeys.MODEL_STORE_PREFIX + "operations", jsonArray.toString())
+
+        // simulate a background thread to load operations
+        val backgroundThread =
+            Thread {
+                operationModelStore.loadOperations()
+            }
+
+        val mainThread =
+            Thread {
+                operationModelStore.add(newOperation)
+            }
+
+        backgroundThread.start()
+        mainThread.start()
+
+        mainThread.join(100)
+
+        // Then
+        // insertion from the main thread is done without blocking
+        operationModelStore.list().count() shouldBe 1
+        operationModelStore.list().first() shouldBe newOperation
+    }
+
     test("Deadlock related to Model.setOptAnyProperty") {
         // Given
         val modelStore = MockHelper.configModelStore()