Reject unsupported identity transform types (#3517)

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# Rationale for this change

Per spec[1], the identity transform source type must be any primitive
except for geometry, geography, and variant. This PR rejects
GeographyType and GeometryType as source types for identity
transforms.(No VariantType yet)

[1] https://iceberg.apache.org/spec/#partition-transforms

## Are these changes tested?

Yes

## Are there any user-facing changes?

No

Author: zhjwpku

pyiceberg/transforms.py

@@ -73,6 +73,8 @@
     DateType,
     DecimalType,
     FixedType,
+    GeographyType,
+    GeometryType,
     IcebergType,
     IntegerType,
     LongType,
@@ -717,7 +719,8 @@ def transform(self, source: IcebergType) -> Callable[[S | None], S | None]:
         return lambda v: v
 
     def can_transform(self, source: IcebergType) -> bool:
-        return source.is_primitive
+        # TODO: disallow VariantType when PyIceberg supports it.
+        return source.is_primitive and not isinstance(source, (GeographyType, GeometryType))
 
     def result_type(self, source: IcebergType) -> IcebergType:
         return source

tests/test_transforms.py

@@ -101,6 +101,8 @@
     DoubleType,
     FixedType,
     FloatType,
+    GeographyType,
+    GeometryType,
     IntegerType,
     LongType,
     NestedField,
@@ -255,6 +257,11 @@ def test_identity_transform_unknown_type() -> None:
     assert IdentityTransform().to_human_string(UnknownType(), None) == "null"
 
 
+@pytest.mark.parametrize("type_var", [GeometryType(), GeographyType()])
+def test_identity_can_transform_unsupported_type(type_var: PrimitiveType) -> None:
+    assert not IdentityTransform().can_transform(type_var)
+
+
 def test_string_with_surrogate_pair() -> None:
     string_with_surrogate_pair = "string with a surrogate pair: 💰"
     as_bytes = bytes(string_with_surrogate_pair, UTF8)