Make true/false expression JSON serializable

pyiceberg/expressions/__init__.py

@@ -32,14 +32,16 @@
     Union,
 )
 
+from pydantic import Field
+
 from pyiceberg.expressions.literals import (
     AboveMax,
     BelowMin,
     Literal,
     literal,
 )
 from pyiceberg.schema import Accessor, Schema
-from pyiceberg.typedef import L, StructProtocol
+from pyiceberg.typedef import L, StructProtocol, IcebergRootModel
 from pyiceberg.types import DoubleType, FloatType, NestedField
 from pyiceberg.utils.singleton import Singleton
 
@@ -362,9 +364,10 @@ def __getnewargs__(self) -> Tuple[BooleanExpression]:
         return (self.child,)
 
 
-class AlwaysTrue(BooleanExpression, Singleton):
+class AlwaysTrue(IcebergRootModel, BooleanExpression, Singleton):
     """TRUE expression."""
 
+    root: str = Field(default="true")
     def __invert__(self) -> AlwaysFalse:
         """Transform the Expression into its negated version."""
         return AlwaysFalse()
@@ -378,9 +381,10 @@ def __repr__(self) -> str:
         return "AlwaysTrue()"
 
 
-class AlwaysFalse(BooleanExpression, Singleton):
+class AlwaysFalse(IcebergRootModel, BooleanExpression, Singleton):
     """FALSE expression."""
 
+    root: str = Field(default="false")
     def __invert__(self) -> AlwaysTrue:
         """Transform the Expression into its negated version."""
         return AlwaysTrue()

tests/table/test_partitioning.py

@@ -20,7 +20,7 @@
 from uuid import UUID
 
 import pytest
-
+from pyiceberg.expressions import AlwaysTrue, AlwaysFalse
 from pyiceberg.partitioning import UNPARTITIONED_PARTITION_SPEC, PartitionField, PartitionSpec
 from pyiceberg.schema import Schema
 from pyiceberg.transforms import (
@@ -32,7 +32,7 @@
     TruncateTransform,
     YearTransform,
 )
-from pyiceberg.typedef import Record
+from pyiceberg.typedef import Record, IcebergBaseModel
 from pyiceberg.types import (
     BinaryType,
     DateType,
@@ -112,6 +112,36 @@ def test_unpartitioned() -> None:
 def test_serialize_unpartitioned_spec() -> None:
     assert UNPARTITIONED_PARTITION_SPEC.model_dump_json() == """{"spec-id":0,"fields":[]}"""
 
+def test_always_true_serializes_to_json_true():
+    expr = AlwaysTrue()
+    assert expr.model_dump_json() == "true"
+
+def test_always_false_serializes_to_json_false():
+    expr = AlwaysFalse()
+    assert expr.model_dump_json() == "false"
+
+def test_serialize_partition_spec_trye() -> None:
+    partitioned = PartitionSpec(
+        PartitionField(source_id=1, field_id=1000, transform=TruncateTransform(width=19), name="str_truncate"),
+        PartitionField(source_id=2, field_id=1001, transform=BucketTransform(num_buckets=25), name="int_bucket"),
+        spec_id=3,
+    )
+    assert (
+        partitioned.model_dump_json()
+        == """{"spec-id":3,"fields":[{"source-id":1,"field-id":1000,"transform":"truncate[19]","name":"str_truncate"},{"source-id":2,"field-id":1001,"transform":"bucket[25]","name":"int_bucket"}]}"""
+    )
+
+def test_serialize_partition_spec() -> None:
+    partitioned = PartitionSpec(
+        PartitionField(source_id=1, field_id=1000, transform=TruncateTransform(width=19), name="str_truncate"),
+        PartitionField(source_id=2, field_id=1001, transform=BucketTransform(num_buckets=25), name="int_bucket"),
+        spec_id=3,
+    )
+    assert (
+        partitioned.model_dump_json()
+        == """{"spec-id":3,"fields":[{"source-id":1,"field-id":1000,"transform":"truncate[19]","name":"str_truncate"},{"source-id":2,"field-id":1001,"transform":"bucket[25]","name":"int_bucket"}]}"""
+    )
+
 
 def test_serialize_partition_spec() -> None:
     partitioned = PartitionSpec(