From 378f73721f960422a4439e0b68f24c645d5a137e Mon Sep 17 00:00:00 2001
From: "Jeong, YunWon" <jeong@youknowone.org>
Date: Sat, 31 Jan 2026 07:14:07 +0900
Subject: [PATCH] slot_del

---
 crates/vm/src/object/core.rs | 26 +++++++++++++++++++++++++-
 1 file changed, 25 insertions(+), 1 deletion(-)

diff --git a/crates/vm/src/object/core.rs b/crates/vm/src/object/core.rs
index 43b2f7dc61a..173b47a757a 100644
--- a/crates/vm/src/object/core.rs
+++ b/crates/vm/src/object/core.rs
@@ -220,6 +220,11 @@ impl WeakRefList {
             }))
         });
         let mut inner = unsafe { inner_ptr.as_ref().lock() };
+        // If obj was cleared but object is still alive (e.g., new weakref
+        // created during __del__), restore the obj pointer
+        if inner.obj.is_none() {
+            inner.obj = Some(NonNull::from(obj));
+        }
         if is_generic && let Some(generic_weakref) = inner.generic_weakref {
             let generic_weakref = unsafe { generic_weakref.as_ref() };
             if generic_weakref.0.ref_count.get() != 0 {
@@ -835,15 +840,34 @@ impl PyObject {
             slot_del: fn(&PyObject, &VirtualMachine) -> PyResult<()>,
         ) -> Result<(), ()> {
             let ret = crate::vm::thread::with_vm(zelf, |vm| {
+                // Increment twice (0→2) so we can decrement twice below.
+                zelf.0.ref_count.inc();
                 zelf.0.ref_count.inc();
+                let after_inc = zelf.strong_count(); // Should be 2
+
                 if let Err(e) = slot_del(zelf, vm) {
                     let del_method = zelf.get_class_attr(identifier!(vm, __del__)).unwrap();
                     vm.run_unraisable(e, None, del_method);
                 }
+
+                let after_del = zelf.strong_count();
+
+                // First decrement
+                zelf.0.ref_count.dec();
+
+                // Check for resurrection: if ref_count increased beyond our expected 2,
+                // then __del__ created new references (resurrection occurred).
+                if after_del > after_inc {
+                    // Resurrected - don't do second decrement, leave object alive
+                    return false;
+                }
+
+                // No resurrection - do second decrement to get back to 0
+                // This matches the double increment from inc()
                 zelf.0.ref_count.dec()
             });
             match ret {
-                // the decref right above set ref_count back to 0
+                // the decref set ref_count back to 0
                 Some(true) => Ok(()),
                 // we've been resurrected by __del__
                 Some(false) => Err(()),