call py.allow_threads before expensive calls in python bindings

Author: ngoldbaum

native/libcst/src/py.rs

@@ -8,24 +8,30 @@ use pyo3::prelude::*;
 
 #[pymodule(gil_used = false)]
 #[pyo3(name = "native")]
-pub fn libcst_native(_py: Python, m: &Bound<PyModule>) -> PyResult<()> {
+pub fn libcst_native(m: &Bound<PyModule>) -> PyResult<()> {
     #[pyfn(m)]
     #[pyo3(signature = (source, encoding=None))]
     fn parse_module(source: String, encoding: Option<&str>) -> PyResult<PyObject> {
-        let m = crate::parse_module(source.as_str(), encoding)?;
-        Python::with_gil(|py| m.try_into_py(py))
+        Python::with_gil(|py| {
+            let m = py.allow_threads(|| crate::parse_module(source.as_str(), encoding))?;
+            m.try_into_py(py)
+        })
     }
 
     #[pyfn(m)]
     fn parse_expression(source: String) -> PyResult<PyObject> {
-        let expr = crate::parse_expression(source.as_str())?;
-        Python::with_gil(|py| expr.try_into_py(py))
+        Python::with_gil(|py| {
+            let expr = py.allow_threads(|| crate::parse_expression(source.as_str()))?;
+            expr.try_into_py(py)
+        })
     }
 
     #[pyfn(m)]
     fn parse_statement(source: String) -> PyResult<PyObject> {
-        let stm = crate::parse_statement(source.as_str())?;
-        Python::with_gil(|py| stm.try_into_py(py))
+        Python::with_gil(|py| {
+            let stm = py.allow_threads(|| crate::parse_statement(source.as_str()))?;
+            stm.try_into_py(py)
+        })
     }
 
     Ok(())