Fix segfault in RawTableProvider by keeping SessionContext alive

The FFI_TableProvider stores a Weak reference to the TaskContextProvider,
but the Arc was created locally and dropped immediately. Use a static
OnceLock to keep it alive. Also update the __datafusion_table_provider__
signature for the v52 protocol and bump datafusion dependency to >=52.0.0.

Author: hozan23

python/pyproject.toml

@@ -8,7 +8,7 @@ version = "0.1.0"
 description = "Build and run queries against data"
 readme = "../README.md"
 license = { file = "../LICENSE" }
-requires-python = ">=3.9"
+requires-python = ">=3.10"
 keywords = ["datafusion", "dataframe", "rust", "query-engine"]
 classifier = [
     "Development Status :: 2 - Pre-Alpha",
@@ -24,7 +24,7 @@ classifier = [
     "Programming Language :: Python",
     "Programming Language :: Rust",
 ]
-dependencies = ["datafusion>=45.0.0"]
+dependencies = ["datafusion>=52.0.0"]
 
 [project.urls]
 repository = "https://github.com/datafusion-contrib/datafusion-table-providers"

python/src/lib.rs

@@ -19,11 +19,20 @@ pub(crate) fn get_tokio_runtime() -> &'static tokio::runtime::Runtime {
     RUNTIME.get_or_init(|| tokio::runtime::Runtime::new().expect("Failed to create Tokio runtime"))
 }
 
+/// Returns a static reference to a default SessionContext.
+/// This ensures the Arc backing the Weak reference inside
+/// FFI_TaskContextProvider is never dropped.
+fn get_default_session_context() -> &'static Arc<SessionContext> {
+    static CTX: OnceLock<Arc<SessionContext>> = OnceLock::new();
+    CTX.get_or_init(|| Arc::new(SessionContext::default()))
+}
+
 #[pymethods]
 impl RawTableProvider {
     fn __datafusion_table_provider__<'py>(
         &self,
         py: Python<'py>,
+        _session: Bound<'py, PyAny>,
     ) -> PyResult<Bound<'py, PyCapsule>> {
         let name = CString::new("datafusion_table_provider").unwrap();
 
@@ -33,7 +42,7 @@ impl RawTableProvider {
             None
         };
 
-        let ctx = Arc::new(SessionContext::default()) as Arc<dyn TaskContextProvider>;
+        let ctx = Arc::clone(get_default_session_context()) as Arc<dyn TaskContextProvider>;
         let provider = FFI_TableProvider::new(
             Arc::clone(&self.table),
             self.supports_pushdown_filters,