From 129aeacf484fc84e90a817528a76b3ea61c1ad33 Mon Sep 17 00:00:00 2001
From: Ramanpreet Nara <ramanpreet@fb.com>
Date: Tue, 16 Apr 2019 09:14:12 -0700
Subject: [PATCH] Add exception handling to method invocations

Summary:
If you call into a Java method (from C++ using JNI) that raises an exception, the JNI call won't actually raise a C++ error. Instead, the `JNIEnv` will record the pending Java exception and the C++ will continue executing as normal. This is bad because the next time you call into JNI, the app will actually crash, unless you explicitly cleared the exception using `JNIEnv::ExceptionClear()` before the JNI call.

With respect to TurboModules, we need to make sure that RedBoxes show up whenever a native methods raise an exception. We also don't want the app to crash when a JNI method call fails because of a raised exception. Therefore, in this diff, I raise a C++ exception if `JNIEnv::ExceptionCheck()` is true.

Reviewed By: mdvacca

Differential Revision: D14738540

fbshipit-source-id: 4c3063aa93ae7aef025bd2dab6b45059bb8fb409
---
 .../core/platform/android/JavaTurboModule.cpp | 41 +++++++++++++++++--
 1 file changed, 37 insertions(+), 4 deletions(-)

diff --git a/ReactCommon/turbomodule/core/platform/android/JavaTurboModule.cpp b/ReactCommon/turbomodule/core/platform/android/JavaTurboModule.cpp
index fbedfeff623..fa54312c483 100644
--- a/ReactCommon/turbomodule/core/platform/android/JavaTurboModule.cpp
+++ b/ReactCommon/turbomodule/core/platform/android/JavaTurboModule.cpp
@@ -143,6 +143,23 @@ jsi::Value JavaTurboModule::get(jsi::Runtime& runtime, const jsi::PropNameID& pr
   }
 }
 
+static void throwIfJNIReportsPendingException() {
+  JNIEnv *env = jni::Environment::current();
+  if (env->ExceptionCheck()) {
+    jthrowable ex = env->ExceptionOccurred();
+
+    // There should be no pending exceptions before we call into JNI
+    env->ExceptionClear();
+
+    auto exception = jni::adopt_local(ex);
+    auto getMessage =
+        exception->getClass()->getMethod<std::string()>("getMessage");
+    auto message = getMessage(exception)->toStdString();
+
+    throw std::runtime_error(message);
+  }
+}
+
 jsi::Value JavaTurboModule::invokeJavaMethod(
     jsi::Runtime &runtime,
     TurboModuleMethodValueKind valueKind,
@@ -166,19 +183,29 @@ jsi::Value JavaTurboModule::invokeJavaMethod(
   switch (valueKind) {
     case VoidKind: {
       env->CallVoidMethodA(instance, methodID, jargs.data());
+      throwIfJNIReportsPendingException();
+
       return jsi::Value::undefined();
     }
     case BooleanKind: {
-      return jsi::Value(
-          (bool)env->CallBooleanMethodA(instance, methodID, jargs.data()));
+      bool returnBoolean =
+          (bool)env->CallBooleanMethodA(instance, methodID, jargs.data());
+      throwIfJNIReportsPendingException();
+
+      return jsi::Value(returnBoolean);
     }
     case NumberKind: {
-      return jsi::Value(
-          (double)env->CallDoubleMethodA(instance, methodID, jargs.data()));
+      double returnDouble =
+          (double)env->CallDoubleMethodA(instance, methodID, jargs.data());
+      throwIfJNIReportsPendingException();
+
+      return jsi::Value(returnDouble);
     }
     case StringKind: {
       auto returnString =
           (jstring)env->CallObjectMethodA(instance, methodID, jargs.data());
+      throwIfJNIReportsPendingException();
+
       if (returnString == nullptr) {
         return jsi::Value::null();
       }
@@ -190,6 +217,8 @@ jsi::Value JavaTurboModule::invokeJavaMethod(
     case ObjectKind: {
       auto returnObject =
           (jobject)env->CallObjectMethodA(instance, methodID, jargs.data());
+      throwIfJNIReportsPendingException();
+
       if (returnObject == nullptr) {
         return jsi::Value::null();
       }
@@ -200,6 +229,8 @@ jsi::Value JavaTurboModule::invokeJavaMethod(
     case ArrayKind: {
       auto returnObject =
           (jobject)env->CallObjectMethodA(instance, methodID, jargs.data());
+      throwIfJNIReportsPendingException();
+
       if (returnObject == nullptr) {
         return jsi::Value::null();
       }
@@ -254,6 +285,8 @@ jsi::Value JavaTurboModule::invokeJavaMethod(
 
       jsi::Value promise =
           Promise.callAsConstructor(runtime, promiseConstructorArg);
+      throwIfJNIReportsPendingException();
+
       return promise;
     }
     default: