mrousavy · skjolber · Jul 17, 2026
diff --git a/...ple/.harness/crash-reports/2026-07-17T14-50-51-361Z--android--android--logcat--logcat.txt b/...ple/.harness/crash-reports/2026-07-17T14-50-51-361Z--android--android--logcat--logcat.txt
@@ -0,0 +1,36 @@
+--------- beginning of crash
+07-17 16:50:54.323  9295  9295 E AndroidRuntime: FATAL EXCEPTION: main
+07-17 16:50:54.323  9295  9295 E AndroidRuntime: Process: com.margelo.nitroexample, PID: 9295
+07-17 16:50:54.323  9295  9295 E AndroidRuntime: com.facebook.soloader.SoLoaderDSONotFoundError: couldn't find DSO to load: libreactnative.so
+07-17 16:50:54.323  9295  9295 E AndroidRuntime: 	existing SO sources: 
+07-17 16:50:54.323  9295  9295 E AndroidRuntime: 		SoSource 0: ApplicationSoSource[DirectorySoSource[root = /data/app/~~ltrc45ffcQoMl_alJJueQw==/com.margelo.nitroexample--0m3_FOd2upKxHOUO5Z-Sg==/lib/arm64 flags = 0]]
+07-17 16:50:54.323  9295  9295 E AndroidRuntime: 		SoSource 1: DirectApkSoSource[root = [/data/app/~~ltrc45ffcQoMl_alJJueQw==/com.margelo.nitroexample--0m3_FOd2upKxHOUO5Z-Sg==/base.apk!/lib/x86_64]]
+07-17 16:50:54.323  9295  9295 E AndroidRuntime: 		SoSource 2: DirectorySoSource[root = /system/lib64 flags = 3]
+07-17 16:50:54.323  9295  9295 E AndroidRuntime: 		SoSource 3: DirectorySoSource[root = /vendor/lib64 flags = 3]
+07-17 16:50:54.323  9295  9295 E AndroidRuntime: 	Native lib dir: /data/app/~~ltrc45ffcQoMl_alJJueQw==/com.margelo.nitroexample--0m3_FOd2upKxHOUO5Z-Sg==/lib/arm64
+07-17 16:50:54.323  9295  9295 E AndroidRuntime: 
+07-17 16:50:54.323  9295  9295 E AndroidRuntime: 	at com.facebook.soloader.SoLoader.doLoadLibraryBySoName(SoLoader.java:1216)
+07-17 16:50:54.323  9295  9295 E AndroidRuntime: 	at com.facebook.soloader.SoLoader.loadLibraryBySoNameImpl(SoLoader.java:1078)
+07-17 16:50:54.323  9295  9295 E AndroidRuntime: 	at com.facebook.soloader.SoLoader.loadLibraryBySoName(SoLoader.java:943)
+07-17 16:50:54.323  9295  9295 E AndroidRuntime: 	at com.facebook.soloader.SoLoader.loadLibraryOnAndroid(SoLoader.java:859)
+07-17 16:50:54.323  9295  9295 E AndroidRuntime: 	at com.facebook.soloader.SoLoader.loadLibrary(SoLoader.java:842)
+07-17 16:50:54.323  9295  9295 E AndroidRuntime: 	at com.facebook.soloader.SoLoader.loadLibrary(SoLoader.java:812)
+07-17 16:50:54.323  9295  9295 E AndroidRuntime: 	at com.facebook.react.internal.featureflags.ReactNativeFeatureFlagsCxxInterop.<clinit>(ReactNativeFeatureFlagsCxxInterop.kt:28)
+07-17 16:50:54.323  9295  9295 E AndroidRuntime: 	at com.facebook.react.internal.featureflags.ReactNativeFeatureFlagsCxxAccessor.override(ReactNativeFeatureFlagsCxxAccessor.kt:925)
+07-17 16:50:54.323  9295  9295 E AndroidRuntime: 	at com.facebook.react.internal.featureflags.ReactNativeFeatureFlags.override(ReactNativeFeatureFlags.kt:588)
+07-17 16:50:54.323  9295  9295 E AndroidRuntime: 	at com.facebook.react.defaults.DefaultNewArchitectureEntryPoint.load(DefaultNewArchitectureEntryPoint.kt:101)
+07-17 16:50:54.323  9295  9295 E AndroidRuntime: 	at com.facebook.react.defaults.DefaultNewArchitectureEntryPoint.load(DefaultNewArchitectureEntryPoint.kt:43)
+07-17 16:50:54.323  9295  9295 E AndroidRuntime: 	at com.facebook.react.ReactNativeApplicationEntryPoint.loadReactNative(ReactNativeApplicationEntryPoint.java:31)
+07-17 16:50:54.323  9295  9295 E AndroidRuntime: 	at com.margelo.nitroexample.MainApplication.onCreate(MainApplication.kt:29)
+07-17 16:50:54.323  9295  9295 E AndroidRuntime: 	at android.app.Instrumentation.callApplicationOnCreate(Instrumentation.java:1396)
+07-17 16:50:54.323  9295  9295 E AndroidRuntime: 	at android.app.ActivityThread.handleBindApplication(ActivityThread.java:8365)
+07-17 16:50:54.323  9295  9295 E AndroidRuntime: 	at android.app.ActivityThread.-$$Nest$mhandleBindApplication(ActivityThread.java:0)
+07-17 16:50:54.323  9295  9295 E AndroidRuntime: 	at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2776)
+07-17 16:50:54.323  9295  9295 E AndroidRuntime: 	at android.os.Handler.dispatchMessageImpl(Handler.java:142)
+07-17 16:50:54.323  9295  9295 E AndroidRuntime: 	at android.os.Handler.dispatchMessage(Handler.java:126)
+07-17 16:50:54.323  9295  9295 E AndroidRuntime: 	at android.os.Looper.loopOnce(Looper.java:295)
+07-17 16:50:54.323  9295  9295 E AndroidRuntime: 	at android.os.Looper.loop(Looper.java:398)
+07-17 16:50:54.323  9295  9295 E AndroidRuntime: 	at android.app.ActivityThread.main(ActivityThread.java:9572)
+07-17 16:50:54.323  9295  9295 E AndroidRuntime: 	at java.lang.reflect.Method.invoke(Native Method)
+07-17 16:50:54.323  9295  9295 E AndroidRuntime: 	at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:575)
+07-17 16:50:54.323  9295  9295 E AndroidRuntime: 	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:842)
diff --git a/example/.harness/manifest.js b/example/.harness/manifest.js
@@ -0,0 +1,4 @@
+global.RN_HARNESS = { 
+    appRegistryComponentName: 'NitroExample',
+    disableViewFlattening: false,
+  };
diff --git a/example/__tests__/nitro.harness.ts b/example/__tests__/nitro.harness.ts
@@ -4,7 +4,7 @@ import type {
   TestObjectCpp,
   TestObjectSwiftKotlin,
 } from 'react-native-nitro-test'
-import { getTests } from '../src/getTests'
+import { getTests, getIssue1439Tests } from '../src/getTests'
 import { harnessBackend } from '../src/testing/backends/harness'
 
 function createTestRunner(
@@ -32,3 +32,14 @@ const testObjectSwiftKotlin =
 
 describe('TestObject (C++)', createTestRunner(testObjectCpp))
 describe('TestObject (Swift/Kotlin)', createTestRunner(testObjectSwiftKotlin))
+describe('Issue 1439', () => {
+  const tests = getIssue1439Tests({ backend: harnessBackend })
+  for (const test of tests) {
+    it(test.name, async () => {
+      const result = await test.run()
+      if (result.status === 'failed') {
+        throw new Error(result.message)
+      }
+    })
+  }
+})
diff --git a/example/src/getTests.ts b/example/src/getTests.ts
@@ -13,6 +13,7 @@ import {
   Base,
   HybridPlatformObject,
   HybridChild,
+  HybridIssue1439,
 } from 'react-native-nitro-test'
 import {
   type AssertionBackend,
@@ -2444,3 +2445,65 @@ export function getTests(
     ),
   ]
 }
+
+/**
+ * Tests reproducing https://github.com/mrousavy/nitro/issues/1439
+ *
+ * A JS async function is passed inside a struct to native code.
+ * Native calls it twice from a background thread — first call throws, second should succeed.
+ */
+export function getIssue1439Tests(options: GetTestsOptions = {}): TestRunner[] {
+  const backend = options.backend ?? throwingBackend
+  const { it } = createTestRunner(backend)
+  const createTest = createCreateTest()
+
+  return [
+    createTest(
+      '[Issue #1439] Second fn invocation succeeds when first threw',
+      async () =>
+        (
+          await it(async () => {
+            let callCount = 0
+            const result = await HybridIssue1439.callFnTwiceFirstThrows({
+              fn: async (input) => {
+                callCount++
+                if (input.value === 'first') {
+                  throw new Error('Expected error on first call')
+                }
+                return input.value
+              },
+            })
+            if (callCount !== 2) {
+              throw new Error(
+                `Expected fn to be called twice, got ${callCount}`
+              )
+            }
+            return result
+          })
+        )
+          .didNotThrow()
+          .equals('second')
+    ),
+    createTest(
+      '[Issue #1439] fn in struct can be called multiple times without error',
+      async () =>
+        (
+          await it(async () => {
+            const results: string[] = []
+            await HybridIssue1439.callFnTwiceFirstThrows({
+              fn: async (input) => {
+                if (input.value === 'first') {
+                  throw new Error('Expected error on first call')
+                }
+                results.push(input.value)
+                return input.value
+              },
+            })
+            return results.join(',')
+          })
+        )
+          .didNotThrow()
+          .equals('second')
+    ),
+  ]
+}
diff --git a/example/src/screens/HybridObjectTestsScreen.tsx b/example/src/screens/HybridObjectTestsScreen.tsx
@@ -15,7 +15,7 @@ import {
   HybridChild,
   HybridBase,
 } from 'react-native-nitro-test'
-import { getTests, type TestRunner } from '../getTests'
+import { getTests, getIssue1439Tests, type TestRunner } from '../getTests'
 import { logPrototypeChain } from '../logPrototypeChain'
 import SegmentedControl from '@react-native-segmented-control/segmented-control'
 import { NitroModules } from 'react-native-nitro-modules'
@@ -53,7 +53,10 @@ export function HybridObjectTestsScreen() {
   ]
   console.log(`Showing Tests for HybridObject "${selectedObject?.name}"`)
   const allTests = React.useMemo(
-    () => getTests(selectedObject ?? HybridTestObjectCpp),
+    () => [
+      ...getTests(selectedObject ?? HybridTestObjectCpp),
+      ...getIssue1439Tests(),
+    ],
     [selectedObject]
   )
   const [unfilteredTests, setTests] = React.useState<TestState[]>(() =>

diff --git a/...ct-native-nitro-test/android/src/main/java/com/margelo/nitro/test/CustomContinuation.java b/...ct-native-nitro-test/android/src/main/java/com/margelo/nitro/test/CustomContinuation.java
@@ -0,0 +1,59 @@
+package com.margelo.nitro.test;
+
+import org.jetbrains.annotations.NotNull;
+
+import java.util.concurrent.CompletableFuture;
+
+import kotlin.ResultKt;
+import kotlin.coroutines.Continuation;
+import kotlin.coroutines.CoroutineContext;
+import kotlin.coroutines.EmptyCoroutineContext;
+
+/**
+ * Bridges a Kotlin {@code Continuation<T>} to a Java {@link CompletableFuture}.
+ *
+ * <p>This is the <em>exact</em> pattern used in
+ * {@code JavaHybridAbtMobileClientSDK.java} (lines 627–641) that triggers
+ * https://github.com/mrousavy/nitro/issues/1439.</p>
+ *
+ * <p><strong>The bug:</strong> when the Kotlin {@code suspend fun await()} is called
+ * from Java with this continuation, and the {@code Promise} is <em>already resolved</em>
+ * by the time {@code await()} is called, Kotlin's {@code SafeContinuation} short-circuits:
+ * it returns the value directly from {@code await()} instead of calling
+ * {@link #resumeWith}. The Java caller ignores that return value, calls
+ * {@link CompletableFuture#get()}, and <strong>blocks forever</strong> because
+ * {@link #resumeWith} was never invoked.</p>
+ */
+public class CustomContinuation<T> implements Continuation<T> {
+
+    private final CompletableFuture<T> future;
+
+    public CustomContinuation(CompletableFuture<T> future) {
+        this.future = future;
+    }
+
+    @NotNull
+    @Override
+    public CoroutineContext getContext() {
+        return EmptyCoroutineContext.INSTANCE;
+    }
+
+    /**
+     * Called by Kotlin's coroutine machinery when the {@code Promise} resolves or
+     * rejects <em>asynchronously</em> (i.e. after {@code await()} returned
+     * {@code COROUTINE_SUSPENDED}).
+     *
+     * <p><em>Not</em> called when the Promise is already settled at the time
+     * {@code await()} is invoked — that is the root of the issue.</p>
+     */
+    @Override
+    public void resumeWith(@NotNull Object result) {
+        try {
+            ResultKt.throwOnFailure(result);
+            //noinspection unchecked
+            future.complete((T) result);
+        } catch (Throwable t) {
+            future.completeExceptionally(t);
+        }
+    }
+}
diff --git a/...s/react-native-nitro-test/android/src/main/java/com/margelo/nitro/test/HybridIssue1439.kt b/...s/react-native-nitro-test/android/src/main/java/com/margelo/nitro/test/HybridIssue1439.kt
@@ -0,0 +1,110 @@
+package com.margelo.nitro.test
+
+import android.util.Log
+import androidx.annotation.Keep
+import com.facebook.proguard.annotations.DoNotStrip
+import com.margelo.nitro.core.Promise
+import java.util.concurrent.CompletableFuture
+import java.util.concurrent.ExecutionException
+import java.util.concurrent.Executors
+import java.util.concurrent.TimeUnit
+import java.util.concurrent.TimeoutException
+
+@Keep
+@DoNotStrip
+class HybridIssue1439 : HybridIssue1439Spec() {
+
+  /**
+   * Single-threaded executor pool — mirrors the `IdlingScheduledThreadPoolExecutor`
+   * used in JavaHybridAbtMobileClientSDK.java.
+   */
+  private val executor = Executors.newSingleThreadExecutor { r ->
+    Thread(r, "issue1439-pool-thread-0").also { it.isDaemon = true }
+  }
+
+  /**
+   * Reproduces https://github.com/mrousavy/nitro/issues/1439
+   *
+   * Uses the EXACT pattern from JavaHybridAbtMobileClientSDK.java (lines 627–641):
+   *   - A thread-pool executor (not a coroutine)
+   *   - `call.await(new CustomContinuation<>(future))` from Java
+   *   - `future.get()` blocking wait
+   *
+   * Root cause: when `Promise.await(continuation)` is called from Java/non-coroutine Kotlin
+   * and the Promise is *already resolved*, Kotlin's `SafeContinuation` returns the value
+   * directly from `await()` — without ever invoking `CustomContinuation.resumeWith()`.
+   * The Java caller ignores the return value and calls `future.get()` which blocks forever.
+   *
+   * This happens because the inner Promise (for the second `fn` invocation) can already be
+   * resolved by the time we call `await()` on it, depending on JS thread scheduling.
+   */
+  override fun callFnTwiceFirstThrows(params: Issue1439Params): Promise<String> {
+    val outerPromise = Promise<String>()
+
+    executor.submit {
+      try {
+        // First invocation — expected to throw
+        try {
+          val result = callFnBlockingJavaStyle(params.fn, Issue1439CallInput("first"))
+          Log.w(TAG, "First call unexpectedly succeeded with: $result")
+        } catch (e: Exception) {
+          Log.d(TAG, "First call threw as expected: ${e.message}")
+        }
+
+        // Second invocation — should return "second" but hangs when inner Promise is
+        // already resolved and SafeContinuation returns the value without calling
+        // CustomContinuation.resumeWith(), leaving future2 incomplete.
+        Log.d(TAG, "Starting second invocation...")
+        val result = callFnBlockingJavaStyle(params.fn, Issue1439CallInput("second"))
+        Log.d(TAG, "Second call returned: $result")
+        outerPromise.resolve(result)
+      } catch (e: TimeoutException) {
+        val msg = "Issue #1439: second fn invocation timed out — " +
+          "SafeContinuation swallowed the resume, CompletableFuture.get() blocks forever"
+        Log.e(TAG, msg)
+        outerPromise.reject(RuntimeException(msg, e))
+      } catch (e: Exception) {
+        Log.e(TAG, "callFnTwiceFirstThrows failed: ${e.message}", e)
+        outerPromise.reject(e)
+      }
+    }
+
+    return outerPromise
+  }
+
+  /**
+   * Faithfully mirrors JavaHybridAbtMobileClientSDK.java lines 627–641.
+   *
+   * The critical path that triggers the bug:
+   *
+   * ```java
+   * Promise<Promise<String>> call = fn.invoke(input);
+   *
+   * CompletableFuture<Promise<String>> future1 = new CompletableFuture<>();
+   * call.await(new CustomContinuation<>(future1));   // ← Java calling a Kotlin suspend fun
+   * Promise<String> inner = future1.get();           // blocks until JS dispatched
+   *
+   * CompletableFuture<String> future2 = new CompletableFuture<>();
+   * inner.await(new CustomContinuation<>(future2));  // ← BUG: if inner already resolved,
+   *                                                  //   SafeContinuation returns value directly,
+   *                                                  //   CustomContinuation.resumeWith never called
+   * String result = future2.get();                   // ← hangs forever
+   * ```
+   *
+   * Called from Kotlin via [JavaCallHelper] to stay on the same raw thread.
+   */
+  @Throws(Exception::class)
+  private fun callFnBlockingJavaStyle(
+    fn: (input: Issue1439CallInput) -> Promise<Promise<String>>,
+    input: Issue1439CallInput,
+  ): String {
+    val call: Promise<Promise<String>> = fn(input)
+    return JavaCallHelper.awaitFnBlocking(call, TIMEOUT_SECONDS, TimeUnit.SECONDS)
+  }
+
+  companion object {
+    private const val TAG = "HybridIssue1439"
+    private const val TIMEOUT_SECONDS = 3L
+  }
+}
+