fix

Author: lorenarosati

ffi/src/expressions/kernel_visitor.rs

@@ -500,15 +500,8 @@ impl NullTypeTag {
                 PrimitiveType::Timestamp => (Self::Timestamp, 0, 0),
                 PrimitiveType::TimestampNtz => (Self::TimestampNtz, 0, 0),
                 PrimitiveType::Decimal(dt) => (Self::Decimal, dt.precision(), dt.scale()),
-                // Geometry/Geography carry an SRID string (and for Geography, an edge
-                // algorithm) that cannot fit in the (tag, u8, u8) payload this function
-                // returns. We route them through NullTypeTag::Binary to stay consistent
-                // with the FFI schema visitor (which routes geo columns through
-                // visit_binary): consumers see a uniformly binary view of geo across
-                // schema and expressions in this PR. CRS is lost at the FFI boundary
-                // either way -- there is no side channel for it here. Once real FFI geo
-                // support lands, new NullTypeTag::Geometry / ::Geography variants will
-                // replace this arm.
+                // TODO: Once real FFI geo support lands, new NullTypeTag::Geometry / ::Geography variants
+                // willreplace this arm.
                 PrimitiveType::Geometry(_) | PrimitiveType::Geography(_) => (Self::Binary, 0, 0),
             },
             _ => (Self::NonPrimitive, 0, 0),

ffi/src/schema.rs

@@ -330,17 +330,8 @@ fn visit_schema_impl(schema: &StructType, visitor: &mut EngineSchemaVisitor) ->
             &DataType::DATE => call!(visit_date),
             &DataType::TIMESTAMP => call!(visit_timestamp),
             &DataType::TIMESTAMP_NTZ => call!(visit_timestamp_ntz),
-            // Geometry/Geography are WKB-encoded bytes at the FFI layer -- route through
-            // visit_binary. The SRID (and edge algorithm for Geography) carried on the
-            // kernel PrimitiveType is not surfaced through this visitor; FFI consumers see
-            // only a binary column. The companion null-literal path in
-            // ffi/src/expressions/kernel_visitor.rs emits NullTypeTag::Binary for the same
-            // reason, giving consumers a uniformly binary view across schema and
-            // expressions. This is a pragmatic stub, not a claim that geo is semantically
-            // equivalent to binary -- CRS-aware operations against these columns will
-            // produce meaningless results. Tables with geo columns should not be consumed
-            // through this FFI until dedicated visit_geometry / visit_geography callbacks
-            // carrying the SRID are added.
+            // Geometry/Geography are WKB-encoded bytes at the FFI layer
+            // TODO: Add visit_geometry / visit_geography callbacks carrying the SRID once real FFI geo support lands
             DataType::Primitive(PrimitiveType::Geometry(_))
             | DataType::Primitive(PrimitiveType::Geography(_)) => call!(visit_binary),
         }

kernel/src/engine/arrow_conversion/mod.rs

@@ -176,11 +176,9 @@ impl TryFromKernel<&DataType> for ArrowDataType {
                     PrimitiveType::TimestampNtz => {
                         Ok(ArrowDataType::Timestamp(TimeUnit::Microsecond, None))
                     }
-                    // Geometry/Geography are WKB-encoded bytes at the Arrow layer. The SRID
-                    // (and edge algorithm for Geography) belongs on the ArrowField as
-                    // GeoArrow extension metadata (the `crs` / `edges` keys), not on the
-                    // ArrowDataType itself. Attaching that metadata is deferred to the
-                    // StructField -> ArrowField conversion path.
+                    // Geometry/Geography are WKB-encoded bytes.
+                    // The SRID (and edge algorithm for Geometry) belongs on the ArrowField
+                    // as GeoArrow extension metadata
                     PrimitiveType::Geometry(_) | PrimitiveType::Geography(_) => {
                         Ok(ArrowDataType::Binary)
                     }

kernel/src/engine/arrow_expression/mod.rs

@@ -213,9 +213,6 @@ impl Scalar {
                     "Variant is not supported as scalar yet.",
                 ));
             }
-            // Geometry/Geography are WKB-encoded bytes at the Arrow layer, so null appends
-            // route through the BinaryBuilder path. GeoArrow extension metadata is attached
-            // at the ArrowField level (in a schema), not to the builder produced here.
             DataType::Primitive(PrimitiveType::Geometry(_) | PrimitiveType::Geography(_)) => {
                 append_nulls_as!(array::BinaryBuilder)
             }