Fix domain pickle

src/gt4py/next/common.py

@@ -574,6 +574,12 @@ def replace(self, index: int | Dimension, *named_ranges: NamedRange) -> Domain:
 
         return Domain(dims=dims, ranges=ranges)
 
+    def __getstate__(self):
+        state = self.__dict__.copy()
+        # remove cached property
+        state.pop("slice_at", None)
+        return state
+
 
 FiniteDomain: TypeAlias = Domain[FiniteUnitRange]
 

tests/next_tests/regression_tests/embedded_tests/test_domain_pickle.py

@@ -0,0 +1,13 @@
+import pickle
+
+from gt4py.next import common
+
+I = common.Dimension("I")
+J = common.Dimension("J")
+
+def test_domain_pickle_after_slice():
+    domain = common.domain(((I, (2, 4)), (J, (3, 5))))
+    # use slice_at to populate cached property
+    domain.slice_at[2:5, 5:7]
+
+    pickle.dumps(domain)