Make Not expression JSON serializable

Author: Aniketsy

pyiceberg/expressions/__init__.py

@@ -32,7 +32,7 @@
     Union,
 )
 
-from pydantic import model_validator
+from pydantic import Field, model_validator
 
 from pyiceberg.expressions.literals import (
     AboveMax,

tests/expressions/test_expressions.py

@@ -736,6 +736,29 @@ def test_not() -> None:
     assert not_ == pickle.loads(pickle.dumps(not_))
 
 
+def test_not_json_serialization_and_deserialization() -> None:
+    expr = Not(AlwaysFalse())
+    json_str = expr.model_dump_json()
+    restored = Not.model_validate_json(json_str)
+    assert isinstance(restored, AlwaysTrue)
+
+    expr2 = Not(Not(AlwaysFalse()))
+    json_str2 = expr2.model_dump_json()
+    restored2 = Not.model_validate_json(json_str2)
+    assert isinstance(restored2, AlwaysFalse)
+
+    class DummyExpr(BooleanExpression):
+        def __invert__(self) -> BooleanExpression:
+            return self
+
+    dummy = DummyExpr()
+    not_dummy = Not(child=dummy)
+    json_str3 = not_dummy.model_dump_json()
+    restored3 = Not.model_validate_json(json_str3)
+    assert isinstance(restored3, Not)
+    assert isinstance(restored3.child, DummyExpr)
+
+
 def test_always_true() -> None:
     always_true = AlwaysTrue()
     assert str(always_true) == "AlwaysTrue()"