PyO3: introduce getattr_bound helper

src/rust/engine/src/externs/mod.rs

@@ -167,7 +167,7 @@ pub fn store_bool(py: Python, val: bool) -> Value {
 ///
 /// Gets an attribute of the given value as the given type.
 ///
-pub fn getattr<'py, T>(value: &'py PyAny, field: &str) -> Result<T, String>
+pub fn getattr_bound<'py, T>(value: &Bound<'py, PyAny>, field: &str) -> Result<T, String>
 where
     T: FromPyObject<'py>,
 {
@@ -185,6 +185,13 @@ where
         })
 }
 
+pub fn getattr<'py, T>(value: &'py PyAny, field: &str) -> Result<T, String>
+where
+    T: FromPyObject<'py>,
+{
+    getattr_bound(&value.as_borrowed(), field)
+}
+
 ///
 /// Collect the Values contained within an outer Python Iterable PyObject.
 ///
@@ -212,19 +219,26 @@ pub fn collect_iterable(value: &PyAny) -> Result<Vec<&PyAny>, String> {
 }
 
 /// Read a `FrozenDict[str, T]`.
-pub fn getattr_from_str_frozendict<'p, T: FromPyObject<'p>>(
-    value: &'p PyAny,
+pub fn getattr_from_str_frozendict_bound<'py, T: FromPyObject<'py>>(
+    value: &Bound<'py, PyAny>,
     field: &str,
 ) -> BTreeMap<String, T> {
-    let frozendict = getattr(value, field).unwrap();
-    let pydict: &PyDict = getattr(frozendict, "_data").unwrap();
+    let frozendict: Bound<PyAny> = getattr_bound(value, field).unwrap();
+    let pydict: Bound<PyDict> = getattr_bound(&frozendict, "_data").unwrap();
     pydict
         .items()
         .into_iter()
         .map(|kv_pair| kv_pair.extract().unwrap())
         .collect()
 }
 
+pub fn getattr_from_str_frozendict<'py, T: FromPyObject<'py>>(
+    value: &'py PyAny,
+    field: &str,
+) -> BTreeMap<String, T> {
+    getattr_from_str_frozendict_bound(&value.as_borrowed(), field)
+}
+
 pub fn getattr_as_optional_string(value: &PyAny, field: &str) -> PyResult<Option<String>> {
     // TODO: It's possible to view a python string as a `Cow<str>`, so we could avoid actually
     // cloning in some cases.

src/rust/engine/src/nodes/downloaded_file.rs

@@ -98,17 +98,17 @@ impl DownloadedFile {
         let (url_str, expected_digest, auth_headers, retry_delay_duration, max_attempts) =
             Python::with_gil(|py| {
                 let py_download_file_val = self.0.to_value();
-                let py_download_file = (*py_download_file_val).as_ref(py);
-                let url_str: String = externs::getattr(py_download_file, "url")
+                let py_download_file = (*py_download_file_val).bind(py);
+                let url_str: String = externs::getattr_bound(py_download_file, "url")
                     .map_err(|e| format!("Failed to get `url` for field: {e}"))?;
                 let auth_headers =
-                    externs::getattr_from_str_frozendict(py_download_file, "auth_headers");
+                    externs::getattr_from_str_frozendict_bound(py_download_file, "auth_headers");
                 let py_file_digest: PyFileDigest =
-                    externs::getattr(py_download_file, "expected_digest")?;
+                    externs::getattr_bound(py_download_file, "expected_digest")?;
                 let retry_delay_duration: Duration =
-                    externs::getattr(py_download_file, "retry_error_duration")?;
+                    externs::getattr_bound(py_download_file, "retry_error_duration")?;
                 let max_attempts: NonZeroUsize =
-                    externs::getattr(py_download_file, "max_attempts")?;
+                    externs::getattr_bound(py_download_file, "max_attempts")?;
                 Ok::<_, String>((
                     url_str,
                     py_file_digest.0,

src/rust/engine/src/python.rs

@@ -312,6 +312,11 @@ impl Value {
             Err(arc_handle) => arc_handle.clone_ref(py),
         }
     }
+
+    /// Bind this value to the given Pythn context as a `pyo3::Bound` smart pointer.
+    pub fn bind<'py>(&self, py: Python<'py>) -> &Bound<'py, PyAny> {
+        self.0.bind(py)
+    }
 }
 
 impl workunit_store::Value for Value {