From 106d47f4d3e8ea1e114a11f2bec1b1c7eb93d13d Mon Sep 17 00:00:00 2001
From: Matthias Diener <mdiener@illinois.edu>
Date: Wed, 6 Dec 2023 17:27:50 -0600
Subject: [PATCH] Do not store cached hash value when pickling

---
 immutabledict/__init__.py | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/immutabledict/__init__.py b/immutabledict/__init__.py
index 152ce4e..0d04ae5 100644
--- a/immutabledict/__init__.py
+++ b/immutabledict/__init__.py
@@ -45,6 +45,11 @@ def __new__(cls, *args: Any, **kwargs: Any) -> immutabledict[_K, _V]:  # noqa: D
         setattr(inst, "_hash", None)
         return inst
 
+    def __reduce__(self) -> Tuple[Any, ...]:
+        # Do not stored the cached hash value when pickling
+        # as the value might change across Python invocations.
+        return (self.__class__, (self._dict,))
+
     def __getitem__(self, key: _K) -> _V:
         return self._dict[key]