harmony 鸿蒙JSVM-API FAQs

2025-06-12
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JSVM-API FAQs

Fault Location

If the application crashes, check the call stack to locate the fault. For details, see Application Crash Issues.

If an unexpected behavior occurs during the running of the application, locate the code where the execution fails or the unexpected behavior occurs based on the return value and make further analysis based on the function name. For details, see JSVM-API Execution Failures.

Application Crash Issues

Q: The application crashes when OH_JSVM_RunScript or OH_JSVM_CallFunction is called, and the stack top is SetReturnValue.

   #00 pc 0000000000c68ef0 /system/lib64/ndk/libjsvm.so(v8impl::(anonymous namespace)::FunctionCallbackWrapper::SetReturnValue(JSVM_Value__*)+16)
   #01 pc 0000000000c5ad30 /system/lib64/ndk/libjsvm.so(v8impl::(anonymous namespace)::FunctionCallbackWrapper::Invoke(v8::FunctionCallbackInfo<v8::Value> const&)+332)
   #02 pc 00000000014a9e58 /system/lib64/ndk/libjsvm.so
   #03 pc 00000000014a95d4 /system/lib64/ndk/libjsvm.so(v8::internal::Builtin_HandleApiCall(int, unsigned long*, v8::internal::Isolate*)+176)
   #04 pc 0000000000f7dab4 /system/lib64/ndk/libjsvm.so(Builtins_CEntry_Return1_ArgvOnStack_BuiltinExit+84)
   #05 pc 0000000000eece40 /system/lib64/ndk/libjsvm.so(Builtins_InterpreterEntryTrampoline+288)
   #06 pc 0000000000eece40 /system/lib64/ndk/libjsvm.so(Builtins_InterpreterEntryTrampoline+288)
   #07 pc 0000000000eece40 /system/lib64/ndk/libjsvm.so(Builtins_InterpreterEntryTrampoline+288)
   #08 pc 0000000000eece40 /system/lib64/ndk/libjsvm.so(Builtins_InterpreterEntryTrampoline+288)
   #09 pc 0000000000eece40 /system/lib64/ndk/libjsvm.so(Builtins_InterpreterEntryTrampoline+288)
   #10 pc 0000000000eece40 /system/lib64/ndk/libjsvm.so(Builtins_InterpreterEntryTrampoline+288)
   #11 pc 0000000000eece40 /system/lib64/ndk/libjsvm.so(Builtins_InterpreterEntryTrampoline+288)
   #12 pc 0000000000eece40 /system/lib64/ndk/libjsvm.so(Builtins_InterpreterEntryTrampoline+288)
   #13 pc 0000000000fe09f4 /system/lib64/ndk/libjsvm.so(Builtins_PromiseFulfillReactionJob+52)
   #14 pc 0000000000f155c0 /system/lib64/ndk/libjsvm.so(Builtins_RunMicrotasks+672)
   #15 pc 0000000000eeab54 /system/lib64/ndk/libjsvm.so(Builtins_JSRunMicrotasksEntry+148)
   #16 pc 00000000015bed78 /system/lib64/ndk/libjsvm.so(v8::internal::(anonymous namespace)::Invoke(v8::internal::Isolate*, v8::internal::(anonymous namespace)::InvokeParams const&)+2520)
   #17 pc 00000000015bf50c /system/lib64/ndk/libjsvm.so(v8::internal::(anonymous namespace)::InvokeWithTryCatch(v8::internal::Isolate*, v8::internal::(anonymous namespace)::InvokeParams const&)+104)
   #18 pc 00000000015bf730 /system/lib64/ndk/libjsvm.so(v8::internal::Execution::TryRunMicrotasks(v8::internal::Isolate*, v8::internal::MicrotaskQueue*)+80)
   #19 pc 00000000015ecf4c /system/lib64/ndk/libjsvm.so(v8::internal::MicrotaskQueue::RunMicrotasks(v8::internal::Isolate*)+312)
   #20 pc 00000000015ecd9c /system/lib64/ndk/libjsvm.so(v8::internal::MicrotaskQueue::PerformCheckpointInternal(v8::Isolate*)+52)
   #21 pc 00000000015deaa0 /system/lib64/ndk/libjsvm.so(v8::internal::Isolate::FireCallCompletedCallbackInternal(v8::internal::MicrotaskQueue*)+280)
   #22 pc 00000000014334e8 /system/lib64/ndk/libjsvm.so(v8::CallDepthScope<true>::~CallDepthScope()+248)
   #23 pc 00000000014330a4 /system/lib64/ndk/libjsvm.so(v8::Script::Run(v8::Local<v8::Context>, v8::Local<v8::Data>)+884)
   #24 pc 0000000000c5c2ac /system/lib64/ndk/libjsvm.so(OH_JSVM_RunScript+272)

A: SetReturnValue is used to set the return value of a JS function and is triggered after the native function injected by JS is called. Check whether the return value of the native function is correct. For example, check whether the return value (of the JSVM_Value type) is returned without initialization.

Q: The application crashes when the native function injected during JSVM initialization is executed by JS.

A: Check whether JSVM_CallbackStruct is a variable in the stack. When JSVM_CallbackStruct is used across functions, the lifecycle of JSVM_CallbackStruct must be greater than that of JSVM_Env.

   func {
   	// ...
       JSVM_CallbackStruct param[] = {
           {.data = nullptr, .callback = ConsoleInfo},
           {.data = nullptr, .callback = Add},
       };
       JSVM_PropertyDescriptor descriptor[] = {
           {"consoleinfo", NULL, &param[0], NULL, NULL, NULL, JSVM_DEFAULT},
           {"add", NULL, &param[1], NULL, NULL, NULL, JSVM_DEFAULT},
       };
       // Create env, register native method, and open env scope.
       JSVM_Env env;
       OH_JSVM_CreateEnv(vm, sizeof(descriptor) / sizeof(descriptor[0]), descriptor, &env);
      // ...
       OH_JSVM_DestroyEnv(env);
      // ...
   }

In the previous example, the JSVM instance is closed before the function ends. Therefore, the JSVM_CallbackStruct param in the stack can be used.

Q: The application crashes when OH_JSVM_ReferenceRef, OH_JSVM_ReferenceUnRef, OH_JSVM_CreateReference, or OH_JSVM_DeleteReference is called.

A: Check whether JSVM_Ref is held and released by multiple threads at the same time. For details, see JSVM Instance Shared by Multiple Threads.

Q: The application crashes when a JS data type instance is created (for example, OH_JSVM_CreateDouble) in a JSVM instance. The call stack is as follows:

   #00 pc 0000000001d209e4/system/lib64/ndk/libjsvm.so(v8::base::0S::Abort()+28)
   #01 pc 0000000001408480/system/lib64/ndk/libjsvm.so(v8::Utils::ReportApiFailure(char const*,char const*)+124)
   #02 pc 00000000015c99b8/system/lib64/ndk/libjsvm.so(v8::internal::HandleScope::Extend(v8::internal::Isolate*+200)

A: Check whether HandleScope is correctly used. For details, see Lifecycle Management.

JSVM-API Execution Failures

Q: The JS function parameters failed to be obtained by using OH_JSVM_GetCbInfo.

A: Check whether the function parameters are correctly passed. For details, see Obtaining Arguments Passed from JS.

Q: JSVM_PENDING_EXCEPTION is returned when functions such as OH_JSVM_CreateFunction are called.

A: JSVM_PENDING_EXCEPTION indicates that the JSVM has pending exceptions. The pending exception may be caused by the current call, or an exception thrown by a previous call has not been cleared. You can use OH_JSVM_GetAndClearLastException before the current function is called to check whether there are uncleared exceptions. If there is uncleared exception, check for exception value that is not processed. If the exception is thrown by the current call, handle the exception. You can use OH_JSVM_GetAndClearLastException to obtain and clear the pending exception.