chore: Clone should hold GIL

Author: ovr

packages/cubejs-backend-native/.gitignore

@@ -6,3 +6,5 @@ index.node
 **/node_modules
 **/.DS_Store
 npm-debug.log
+test/__pycache__/
+test/subdir_for_test/__pycache__/

packages/cubejs-backend-native/src/cross/clrepr.rs

@@ -98,9 +98,9 @@ pub enum StringType {
     Safe,
 }
 
-/// Cross language representation is abstraction to transfer values between
+/// Cross-language representation is an abstraction to transfer values between
 /// JavaScript and Python across Rust. Converting between two different languages requires
-/// to use Context which is available on the call (one for python and one for js), which result as
+/// using Context which is available on the call (one for python and one for js), which results as
 /// blocking.
 #[derive(Debug, Clone)]
 pub enum CLRepr {

packages/cubejs-backend-native/src/cross/clrepr_python.rs

@@ -8,7 +8,7 @@ use pyo3::types::{
 };
 use pyo3::{Bound, Py, PyAny, PyErr, PyObject, Python, ToPyObject};
 
-#[derive(Debug, Clone)]
+#[derive(Debug)]
 pub enum PythonRef {
     PyObject(PyObject),
     PyFunction(Py<PyFunction>),
@@ -17,6 +17,16 @@ pub enum PythonRef {
     PyExternalFunction(Py<PyFunction>),
 }
 
+impl Clone for PythonRef {
+    fn clone(&self) -> Self {
+        Python::with_gil(|py| match self {
+            PythonRef::PyObject(obj) => PythonRef::PyObject(obj.clone_ref(py)),
+            PythonRef::PyFunction(fun) => PythonRef::PyFunction(fun.clone_ref(py)),
+            PythonRef::PyExternalFunction(fun) => PythonRef::PyExternalFunction(fun.clone_ref(py)),
+        })
+    }
+}
+
 impl CLRepr {
     /// Convert python value to CLRepr
     pub fn from_python_ref(v: &Bound<'_, PyAny>) -> Result<Self, PyErr> {

packages/cubejs-backend-native/src/cross/py_in_js.rs

@@ -2,7 +2,7 @@ use crate::cross::CLRepr;
 use crate::python::runtime::py_runtime;
 use neon::prelude::*;
 use pyo3::types::PyFunction;
-use pyo3::Py;
+use pyo3::{Py, Python};
 use std::cell::RefCell;
 
 pub struct JsPyFunctionWrapper {
@@ -43,7 +43,7 @@ pub fn cl_repr_py_function_wrapper(mut cx: FunctionContext) -> JsResult<JsPromis
         )?);
     }
 
-    let py_method = this.borrow().fun.clone();
+    let py_method = Python::with_gil(|py| this.borrow().fun.clone_ref(py));
     let py_runtime = match py_runtime() {
         Ok(r) => r,
         Err(err) => return cx.throw_error(format!("Unable to init python runtime: {:?}", err)),