From a288b77c4f775e10c7dc89f1dca9060858e2728f Mon Sep 17 00:00:00 2001
From: Jeong YunWon <jeong@youknowone.org>
Date: Sun, 22 Jun 2025 21:51:06 +0900
Subject: [PATCH] BaseException.__setstate__

---
 Lib/test/test_baseexception.py |  2 --
 vm/src/exceptions.rs           | 18 ++++++++++++++++++
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/Lib/test/test_baseexception.py b/Lib/test/test_baseexception.py
index c2446e549..63bf538aa 100644
--- a/Lib/test/test_baseexception.py
+++ b/Lib/test/test_baseexception.py
@@ -121,8 +121,6 @@ class ExceptionClassTests(unittest.TestCase):
                 [repr(exc), exc.__class__.__name__ + '()'])
         self.interface_test_driver(results)
 
-    # TODO: RUSTPYTHON - BaseException.__setstate__ method not implemented
-    @unittest.expectedFailure
     def test_setstate_refcount_no_crash(self):
         # gh-97591: Acquire strong reference before calling tp_hash slot
         # in PyObject_SetAttr.
diff --git a/vm/src/exceptions.rs b/vm/src/exceptions.rs
index 77829608b..885f82b71 100644
--- a/vm/src/exceptions.rs
+++ b/vm/src/exceptions.rs
@@ -647,6 +647,24 @@ impl PyRef<PyBaseException> {
             vm.new_tuple((self.class().to_owned(), self.args()))
         }
     }
+
+    #[pymethod(magic)]
+    fn setstate(self, state: PyObjectRef, vm: &VirtualMachine) -> PyResult<PyObjectRef> {
+        if !vm.is_none(&state) {
+            let dict = state
+                .downcast::<crate::builtins::PyDict>()
+                .map_err(|_| vm.new_type_error("state is not a dictionary".to_owned()))?;
+
+            for (key, value) in &dict {
+                let key_str = key.str(vm)?;
+                if key_str.as_str().starts_with("__") {
+                    continue;
+                }
+                self.as_object().set_attr(&key_str, value.clone(), vm)?;
+            }
+        }
+        Ok(vm.ctx.none())
+    }
 }
 
 impl Constructor for PyBaseException {