QuickJS: report success from the napi_throw family

Core/Node-API/Source/js_native_api_quickjs.cc

@@ -1586,7 +1586,14 @@ napi_status napi_throw(napi_env env, napi_value error) {
   JSContext* targetCtx = env->current_context ? env->current_context : env->context;
   JS_Throw(targetCtx, JS_DupValue(targetCtx, jsError));
 
-  return napi_set_last_error(env, napi_pending_exception);
+  // Returning napi_pending_exception here would report that the throw itself
+  // failed. node-addon-api's Error::ThrowAsJavaScriptException reacts to that by
+  // re-throwing `Error::New(env)`, which clears the exception it just set and
+  // lets the C++ exception escape the callback wrapper. The escaped error is
+  // then stringified by ExternalCallback::Callback after its handle scope is
+  // gone, which reads freed memory.
+  napi_clear_last_error(env);
+  return napi_ok;
 }
 
 // Throw error
@@ -1602,23 +1609,26 @@ napi_status napi_throw_error(napi_env env, const char* code, const char* msg) {
   }
 
   JS_Throw(env->context, error);
-  return napi_set_last_error(env, napi_pending_exception);
+  napi_clear_last_error(env);
+  return napi_ok;
 }
 
 // Throw type error
 napi_status napi_throw_type_error(napi_env env, const char* code, const char* msg) {
   CHECK_ENV(env);
 
   JS_ThrowTypeError(env->context, "%s", msg ? msg : "");
-  return napi_set_last_error(env, napi_pending_exception);
+  napi_clear_last_error(env);
+  return napi_ok;
 }
 
 // Throw range error
 napi_status napi_throw_range_error(napi_env env, const char* code, const char* msg) {
   CHECK_ENV(env);
 
   JS_ThrowRangeError(env->context, "%s", msg ? msg : "");
-  return napi_set_last_error(env, napi_pending_exception);
+  napi_clear_last_error(env);
+  return napi_ok;
 }
 
 // Create error

Tests/UnitTests/Scripts/tests.ts

@@ -1359,6 +1359,26 @@ describe("URLSearchParams", function () {
         expect(() => paramsSet.set()).to.throw();
     });
 
+    it("should preserve the type and message of an error thrown from native code", function () {
+        // A native throw must reach JS unchanged. When napi_throw reported failure, the
+        // error was replaced by an InternalError reading "Uncaught C++ exception: ...",
+        // built by stringifying an error whose handle scope had already closed.
+        let caught: any;
+        try {
+            // @ts-expect-error
+            paramsSet.set();
+        } catch (e) {
+            caught = e;
+        }
+        expect(caught).to.be.an.instanceOf(Error);
+        expect(caught.name).to.equal("Error");
+        // Not an equality check: the JSI backend prefixes "Exception in HostFunction: ".
+        expect(caught.message).to.contain(
+            "Failed to execute 'set' on 'URLSearchParams': 2 arguments required, but only 0 present"
+        );
+        expect(caught.message).to.not.contain("Uncaught C++ exception");
+    });
+
     it("should add a number and retrieve it as a string from searchParams", function () {
         // Set Number
         paramsSet.set("foo", 400 as any);