Fix TruncateTransform.satisfies_order_of for different widths (#3680)

pyiceberg/transforms.py

@@ -779,7 +779,6 @@ class TruncateTransform(Transform[S, S]):
     """
 
     root: str = Field()
-    _source_type: IcebergType = PrivateAttr()
     _width: PositiveInt = PrivateAttr()
 
     def __init__(self, width: int, **data: Any):
@@ -796,10 +795,6 @@ def result_type(self, source: IcebergType) -> IcebergType:
     def preserves_order(self) -> bool:
         return True
 
-    @property
-    def source_type(self) -> IcebergType:
-        return self._source_type
-
     def project(self, name: str, pred: BoundPredicate) -> UnboundPredicate | None:
         field_type = pred.term.ref().field.field_type
 
@@ -896,11 +891,7 @@ def truncate_func(v: Any) -> Any:
     def satisfies_order_of(self, other: Transform[S, T]) -> bool:
         if self == other:
             return True
-        elif (
-            isinstance(self.source_type, StringType)
-            and isinstance(other, TruncateTransform)
-            and isinstance(other.source_type, StringType)
-        ):
+        elif isinstance(other, TruncateTransform):
             return self.width >= other.width
 
         return False

tests/test_transforms.py

@@ -513,6 +513,32 @@ def test_truncate_method(type_var: PrimitiveType, value: Any, expected_human_str
     assert truncate_transform.satisfies_order_of(truncate_transform)
 
 
+def test_truncate_satisfies_order_of() -> None:
+    # Width comparison
+    assert TruncateTransform(5).satisfies_order_of(TruncateTransform(3))
+    assert TruncateTransform(5).satisfies_order_of(TruncateTransform(5))
+    assert not TruncateTransform(3).satisfies_order_of(TruncateTransform(5))
+    assert TruncateTransform(10).satisfies_order_of(TruncateTransform(1))
+    assert not TruncateTransform(1).satisfies_order_of(TruncateTransform(10))
+    assert TruncateTransform(1).satisfies_order_of(TruncateTransform(1))
+
+    # Cross-transform comparisons
+    assert not TruncateTransform(5).satisfies_order_of(BucketTransform(5))
+    assert not TruncateTransform(5).satisfies_order_of(IdentityTransform())
+    assert not TruncateTransform(5).satisfies_order_of(VoidTransform())
+    assert not TruncateTransform(5).satisfies_order_of(DayTransform())
+    assert not TruncateTransform(5).satisfies_order_of(YearTransform())
+    assert not TruncateTransform(5).satisfies_order_of(UnknownTransform("unknown"))
+
+    # Identity naturally satisfies TruncateTransform because Truncate preserves order
+    assert IdentityTransform().satisfies_order_of(TruncateTransform(5))
+
+    # Verify unused source_type was cleanly removed
+    t = TruncateTransform(5)
+    assert not hasattr(t, "source_type")
+    assert not hasattr(t, "_source_type")
+
+
 def test_unknown_transform() -> None:
     unknown_transform = UnknownTransform("unknown")  # type: ignore
     assert str(unknown_transform) == str(eval(repr(unknown_transform)))