From 3ee058cb45c6309d71cdaa110a47546d1082001e Mon Sep 17 00:00:00 2001
From: Pieter De Baets <pieterdb@meta.com>
Date: Wed, 4 Nov 2026 07:56:31 -0800
Subject: [PATCH] Disable legacy Hermes executor creation (#59753)

Summary:

Keep `HermesExecutor.loadLibrary()` as a compatibility no-op and reject `HermesExecutorFactory.create()` with New Architecture migration guidance.

Changelog:
[Android][Breaking] - Disable legacy Hermes executor creation.

Differential Revision: D129045580
---
 .../hermes/reactexecutor/HermesExecutor.kt    | 23 ++-----------
 .../reactexecutor/HermesExecutorFactory.kt    | 12 ++++++-
 .../HermesExecutorFactoryTest.kt              | 34 +++++++++++++++++++
 3 files changed, 48 insertions(+), 21 deletions(-)
 create mode 100644 packages/react-native/ReactAndroid/src/test/java/com/facebook/hermes/reactexecutor/HermesExecutorFactoryTest.kt

diff --git a/packages/react-native/ReactAndroid/src/main/java/com/facebook/hermes/reactexecutor/HermesExecutor.kt b/packages/react-native/ReactAndroid/src/main/java/com/facebook/hermes/reactexecutor/HermesExecutor.kt
index efeb06a9e793..9491038c6add 100644
--- a/packages/react-native/ReactAndroid/src/main/java/com/facebook/hermes/reactexecutor/HermesExecutor.kt
+++ b/packages/react-native/ReactAndroid/src/main/java/com/facebook/hermes/reactexecutor/HermesExecutor.kt
@@ -10,32 +10,15 @@ package com.facebook.hermes.reactexecutor
 import com.facebook.jni.HybridData
 import com.facebook.jni.annotations.DoNotStrip
 import com.facebook.react.bridge.JavaScriptExecutor
-import com.facebook.react.common.build.ReactBuildConfig
-import com.facebook.soloader.SoLoader
 
 public class HermesExecutor internal constructor(enableDebugger: Boolean, debuggerName: String) :
     JavaScriptExecutor(initHybridDefaultConfig(enableDebugger, debuggerName)) {
 
-  override fun getName(): String = "HermesExecutor$mode"
+  override fun getName(): String = "HermesExecutor"
 
   public companion object {
-    private var mode: String? = null
-
-    init {
-      loadLibrary()
-    }
-
-    @JvmStatic
-    @Throws(UnsatisfiedLinkError::class)
-    public fun loadLibrary() {
-      if (mode == null) {
-        // libhermesvm must be loaded explicitly to invoke its JNI_OnLoad.
-        SoLoader.loadLibrary("hermesvm")
-        SoLoader.loadLibrary("hermes_executor")
-        // libhermes_executor is built differently for Debug & Release so we load the proper mode.
-        mode = if (ReactBuildConfig.DEBUG) "Debug" else "Release"
-      }
-    }
+    /** Retained for compatibility; this method no longer loads native libraries. */
+    @JvmStatic public fun loadLibrary() {}
 
     @DoNotStrip
     @JvmStatic
diff --git a/packages/react-native/ReactAndroid/src/main/java/com/facebook/hermes/reactexecutor/HermesExecutorFactory.kt b/packages/react-native/ReactAndroid/src/main/java/com/facebook/hermes/reactexecutor/HermesExecutorFactory.kt
index 5c31fdbb7aa3..52a415a872eb 100644
--- a/packages/react-native/ReactAndroid/src/main/java/com/facebook/hermes/reactexecutor/HermesExecutorFactory.kt
+++ b/packages/react-native/ReactAndroid/src/main/java/com/facebook/hermes/reactexecutor/HermesExecutorFactory.kt
@@ -25,7 +25,17 @@ public class HermesExecutorFactory : JavaScriptExecutorFactory {
     this.debuggerName = debuggerName
   }
 
-  override fun create(): JavaScriptExecutor = HermesExecutor(enableDebugger, debuggerName)
+  /**
+   * Compatibility factory for the unsupported legacy Hermes executor.
+   *
+   * @throws UnsupportedOperationException when creating an executor; use the New Architecture
+   *   runtime instead.
+   */
+  override fun create(): JavaScriptExecutor {
+    throw UnsupportedOperationException(
+        "HermesExecutorFactory is no longer supported. Use the New Architecture runtime instead.",
+    )
+  }
 
   override fun startSamplingProfiler() {
     enable()
diff --git a/packages/react-native/ReactAndroid/src/test/java/com/facebook/hermes/reactexecutor/HermesExecutorFactoryTest.kt b/packages/react-native/ReactAndroid/src/test/java/com/facebook/hermes/reactexecutor/HermesExecutorFactoryTest.kt
new file mode 100644
index 000000000000..d0e5501e6963
--- /dev/null
+++ b/packages/react-native/ReactAndroid/src/test/java/com/facebook/hermes/reactexecutor/HermesExecutorFactoryTest.kt
@@ -0,0 +1,34 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+package com.facebook.hermes.reactexecutor
+
+import org.assertj.core.api.Assertions.assertThatThrownBy
+import org.junit.Test
+
+class HermesExecutorFactoryTest {
+  @Test
+  fun loadLibraryIsNoOp() {
+    HermesExecutor.loadLibrary()
+    HermesExecutor.loadLibrary()
+  }
+
+  @Test
+  fun createIsUnsupported() {
+    val factory = HermesExecutorFactory()
+    factory.setEnableDebugger(false)
+    factory.setDebuggerName("test")
+
+    repeat(2) {
+      assertThatThrownBy { factory.create() }
+          .isInstanceOf(UnsupportedOperationException::class.java)
+          .hasMessage(
+              "HermesExecutorFactory is no longer supported. Use the New Architecture runtime instead.",
+          )
+    }
+  }
+}