Revert "revert gc"

youknowone · youknowone · commit ef42990ef0ba · 2026-01-21T21:10:32.000+09:00
diff --git a/crates/stdlib/src/gc.rs b/crates/stdlib/src/gc.rs
@@ -2,7 +2,7 @@ pub(crate) use gc::module_def;
 
 #[pymodule]
 mod gc {
-    use crate::vm::{PyResult, VirtualMachine, function::FuncArgs};
+    use crate::vm::{PyObjectRef, PyResult, VirtualMachine, function::FuncArgs};
 
     #[pyfunction]
     fn collect(_args: FuncArgs, _vm: &VirtualMachine) -> i32 {
@@ -45,8 +45,10 @@ mod gc {
     }
 
     #[pyfunction]
-    fn get_referrers(_args: FuncArgs, vm: &VirtualMachine) -> PyResult {
-        Err(vm.new_not_implemented_error(""))
+    fn get_referrers(_args: FuncArgs, vm: &VirtualMachine) -> PyObjectRef {
+        // RustPython does not support bi-directional reference tracking.
+        // Return empty list for compatibility with reference cycle tests.
+        vm.ctx.new_list(vec![]).into()
     }
 
     #[pyfunction]
