Stringify elements of napi_get_property_names.

crates/neon-runtime/src/napi/convert.rs

@@ -1,5 +1,11 @@
-use raw::Local;
+use nodejs_sys as napi;
+
+use raw::{Env, Local};
 
 pub unsafe extern "C" fn to_object(_out: &mut Local, _value: &Local) -> bool { unimplemented!() }
 
-pub unsafe extern "C" fn to_string(_out: &mut Local, _value: Local) -> bool { unimplemented!() }
+pub unsafe extern "C" fn to_string(out: &mut Local, env: Env, value: Local) -> bool {
+    let status = napi::napi_coerce_to_string(env, value, out as *mut _);
+
+    status == napi::napi_status::napi_ok
+}

crates/neon-runtime/src/napi/object.rs

@@ -2,6 +2,9 @@ use std::mem::MaybeUninit;
 
 use nodejs_sys as napi;
 
+use array;
+use convert;
+use tag;
 use raw::{Env, Local};
 
 /// Mutates the `out` argument to refer to a `napi_value` containing a newly created JavaScript Object.
@@ -14,7 +17,36 @@ pub unsafe extern "C" fn new(out: &mut Local, env: Env) {
 pub unsafe extern "C" fn get_own_property_names(out: &mut Local, env: Env, object: Local) -> bool {
     let status = napi::napi_get_property_names(env, object, out as *mut _);
 
-    status == napi::napi_status::napi_ok
+    if status != napi::napi_status::napi_ok {
+        return false;
+    }
+
+    // Before https://github.com/nodejs/node/pull/27524, `napi_get_property_names` would return
+    // numbers for numeric indices instead of strings.
+    let len = array::len(env, *out);
+    for index in 0..len {
+        let mut element: Local = std::mem::zeroed();
+        // In general, getters may cause arbitrary JS code to be run, but this is a newly created
+        // Array from an official internal API so it doesn't do anything strange.
+        if !get_index(&mut element, env, *out, index) {
+            continue;
+        }
+        if tag::is_string(env, element) {
+            continue;
+        }
+        let mut stringified: Local = std::mem::zeroed();
+        // If we can't convert to a string, something went wrong.
+        if !convert::to_string(&mut stringified, env, element) {
+            return false;
+        }
+        let mut dummy = false;
+        // If we can't convert assign to this array, something went wrong.
+        if !set_index(&mut dummy, env, *out, index, stringified) {
+            return false;
+        }
+    }
+
+    true
 }
 
 // Unused.

crates/neon-sys/native/src/neon.cc

@@ -173,7 +173,7 @@ extern "C" size_t Neon_String_Data(char *out, size_t len, v8::Local<v8::Value> s
   return Nan::DecodeWrite(out, len, str, Nan::UTF8);
 }
 
-extern "C" bool Neon_Convert_ToString(v8::Local<v8::String> *out, v8::Local<v8::Value> value) {
+extern "C" bool Neon_Convert_ToString(v8::Local<v8::String> *out, v8::Isolate *isolate, v8::Local<v8::Value> value) {
   Nan::MaybeLocal<v8::String> maybe = Nan::To<v8::String>(value);
   return maybe.ToLocal(out);
 }

crates/neon-sys/native/src/neon.h

@@ -46,7 +46,7 @@ extern "C" {
   int32_t Neon_String_Utf8Length(v8::Local<v8::String> str);
   size_t Neon_String_Data(char *out, size_t len, v8::Local<v8::Value> str);
 
-  bool Neon_Convert_ToString(v8::Local<v8::String> *out, v8::Local<v8::Value> value);
+  bool Neon_Convert_ToString(v8::Local<v8::String> *out, v8::Isolate *isolate, v8::Local<v8::Value> value);
   bool Neon_Convert_ToObject(v8::Local<v8::Object> *out, v8::Local<v8::Value> *value);
 
   bool Neon_Buffer_New(v8::Local<v8::Object> *out, uint32_t size);

crates/neon-sys/src/lib.rs

@@ -123,7 +123,7 @@ extern "C" {
     pub fn Neon_Class_GetInstanceInternals(obj: Local) -> *mut c_void;
 
     pub fn Neon_Convert_ToObject(out: &mut Local, value: &Local) -> bool;
-    pub fn Neon_Convert_ToString(out: &mut Local, value: Local) -> bool;
+    pub fn Neon_Convert_ToString(out: &mut Local, isolate: Isolate, value: Local) -> bool;
 
     pub fn Neon_Error_Throw(val: Local);
     pub fn Neon_Error_NewError(out: &mut Local, msg: Local);

src/types/mod.rs

@@ -50,8 +50,11 @@ impl<T: Object> SuperType<T> for JsObject {
 
 /// The trait shared by all JavaScript values.
 pub trait Value: ValueInternal {
-    fn to_string<'a, C: Context<'a>>(self, _: &mut C) -> JsResult<'a, JsString> {
-        build(|out| { unsafe { neon_runtime::convert::to_string(out, self.to_raw()) } })
+    fn to_string<'a, C: Context<'a>>(self, cx: &mut C) -> JsResult<'a, JsString> {
+        let env = cx.env();
+        build(|out| {
+            unsafe { neon_runtime::convert::to_string(out, env.to_raw(), self.to_raw()) }
+        })
     }
 
     fn as_value<'a, C: Context<'a>>(self, _: &mut C) -> Handle<'a, JsValue> {

test/napi/native/src/lib.rs

@@ -59,8 +59,11 @@ register_module!(|mut cx| {
     let property_names = rust_created.get_own_property_names(&mut cx)?
         .to_vec(&mut cx)?
         .into_iter()
-        .map(|value| value.downcast::<JsString, _>(&mut cx).unwrap().value(&mut cx))
-        .collect::<Vec<_>>();
+        .map(|value| {
+            let string: Handle<JsString> = value.downcast_or_throw(&mut cx)?;
+            Ok(string.value(&mut cx))
+        })
+        .collect::<Result<Vec<_>, _>>()?;
     assert_eq!(property_names, &["0", "a", "whatever"]);
 
     cx.export_value("rustCreated", rust_created)?;