fix(spec): support variant type metadata

.github/workflows/ci.yml

@@ -115,6 +115,13 @@ jobs:
           repo-token: ${{ secrets.GITHUB_TOKEN }}
 
       - name: Build
+        if: matrix.os != 'windows-latest'
+        run: make build
+
+      - name: Build
+        if: matrix.os == 'windows-latest'
+        env:
+          AWS_LC_SYS_C_STD: "11"
         run: make build
 
   build_with_no_default_features:

crates/catalog/glue/src/schema.rs

@@ -165,7 +165,7 @@ impl SchemaVisitor for GlueSchemaBuilder {
             PrimitiveType::Date => "date".to_string(),
             PrimitiveType::Timestamp => "timestamp".to_string(),
             PrimitiveType::TimestampNs => "timestamp_ns".to_string(),
-            PrimitiveType::Timestamptz | PrimitiveType::TimestamptzNs => {
+            PrimitiveType::Timestamptz | PrimitiveType::TimestamptzNs | PrimitiveType::Variant => {
                 return Err(Error::new(
                     ErrorKind::FeatureUnsupported,
                     format!("Conversion from {p:?} is not supported"),

crates/catalog/hms/src/schema.rs

@@ -122,7 +122,7 @@ impl SchemaVisitor for HiveSchemaBuilder {
             PrimitiveType::Date => "date".to_string(),
             PrimitiveType::Timestamp => "timestamp".to_string(),
             PrimitiveType::TimestampNs => "timestamp_ns".to_string(),
-            PrimitiveType::Timestamptz | PrimitiveType::TimestamptzNs => {
+            PrimitiveType::Timestamptz | PrimitiveType::TimestamptzNs | PrimitiveType::Variant => {
                 return Err(Error::new(
                     ErrorKind::FeatureUnsupported,
                     format!("Conversion from {p:?} is not supported"),

crates/iceberg/src/arrow/schema.rs

@@ -687,6 +687,9 @@ impl SchemaVisitor for ToArrowSchemaConverter {
             crate::spec::PrimitiveType::Binary => {
                 Ok(ArrowSchemaOrFieldOrType::Type(DataType::LargeBinary))
             }
+            crate::spec::PrimitiveType::Variant => {
+                Ok(ArrowSchemaOrFieldOrType::Type(DataType::LargeBinary))
+            }
         }
     }
 }
@@ -1119,6 +1122,7 @@ pub fn datum_to_arrow_type_with_ree(datum: &Datum) -> DataType {
         PrimitiveType::Uuid => make_ree(DataType::Binary),
         PrimitiveType::Fixed(_) => make_ree(DataType::Binary),
         PrimitiveType::Binary => make_ree(DataType::Binary),
+        PrimitiveType::Variant => make_ree(DataType::Binary),
         PrimitiveType::Decimal { precision, scale } => {
             make_ree(DataType::Decimal128(*precision as u8, *scale as i8))
         }

crates/iceberg/src/arrow/value.rs

@@ -424,6 +424,10 @@ impl SchemaWithPartnerVisitor<ArrayRef> for ArrowArrayToIcebergStructConverter {
                     ))
                 }
             }
+            PrimitiveType::Variant => Err(Error::new(
+                ErrorKind::FeatureUnsupported,
+                "Converting arrow array to variant literals is not supported yet.",
+            )),
         }
     }
 }

crates/iceberg/src/avro/schema.rs

@@ -237,6 +237,12 @@ impl SchemaVisitor for SchemaToAvroSchema {
             PrimitiveType::Uuid => AvroSchema::Uuid,
             PrimitiveType::Fixed(len) => avro_fixed_schema((*len) as usize)?,
             PrimitiveType::Binary => AvroSchema::Bytes,
+            PrimitiveType::Variant => {
+                return Err(Error::new(
+                    ErrorKind::FeatureUnsupported,
+                    "Converting variant type to avro schema is not supported yet.",
+                ));
+            }
             PrimitiveType::Decimal { precision, scale } => {
                 avro_decimal_schema(*precision as usize, *scale as usize)?
             }

crates/iceberg/src/spec/datatypes.rs

@@ -241,6 +241,8 @@ pub enum PrimitiveType {
     TimestamptzNs,
     /// Arbitrary-length character sequences encoded in utf-8
     String,
+    /// Semi-structured data encoded as an Iceberg variant.
+    Variant,
     /// Universally Unique Identifiers, should use 16-byte fixed
     Uuid,
     /// Fixed length byte array
@@ -379,6 +381,7 @@ impl fmt::Display for PrimitiveType {
             PrimitiveType::TimestampNs => write!(f, "timestamp_ns"),
             PrimitiveType::TimestamptzNs => write!(f, "timestamptz_ns"),
             PrimitiveType::String => write!(f, "string"),
+            PrimitiveType::Variant => write!(f, "variant"),
             PrimitiveType::Uuid => write!(f, "uuid"),
             PrimitiveType::Fixed(size) => write!(f, "fixed({size})"),
             PrimitiveType::Binary => write!(f, "binary"),
@@ -868,7 +871,8 @@ mod tests {
             {"id": 13, "name": "uuid_field", "required": true, "type": "uuid"},
             {"id": 14, "name": "fixed_field", "required": true, "type": "fixed[10]"},
             {"id": 15, "name": "binary_field", "required": true, "type": "binary"},
-            {"id": 16, "name": "string_field", "required": true, "type": "string"}
+            {"id": 16, "name": "string_field", "required": true, "type": "string"},
+            {"id": 17, "name": "variant_field", "required": true, "type": "variant"}
         ]
     }
     "#;
@@ -948,6 +952,12 @@ mod tests {
                         Type::Primitive(PrimitiveType::String),
                     )
                     .into(),
+                    NestedField::required(
+                        17,
+                        "variant_field",
+                        Type::Primitive(PrimitiveType::Variant),
+                    )
+                    .into(),
                 ],
                 id_lookup: OnceLock::default(),
                 name_lookup: OnceLock::default(),

crates/iceberg/src/spec/table_metadata.rs

@@ -1732,6 +1732,12 @@ mod tests {
                                 "name": "ts",
                                 "required": true,
                                 "type": "timestamp"
+                            },
+                            {
+                                "id": 5,
+                                "name": "payload",
+                                "required": false,
+                                "type": "variant"
                             }
                         ]
                     }
@@ -1798,11 +1804,18 @@ mod tests {
 
         let schema = Schema::builder()
             .with_schema_id(1)
-            .with_fields(vec![Arc::new(NestedField::required(
-                4,
-                "ts",
-                Type::Primitive(PrimitiveType::Timestamp),
-            ))])
+            .with_fields(vec![
+                Arc::new(NestedField::required(
+                    4,
+                    "ts",
+                    Type::Primitive(PrimitiveType::Timestamp),
+                )),
+                Arc::new(NestedField::optional(
+                    5,
+                    "payload",
+                    Type::Primitive(PrimitiveType::Variant),
+                )),
+            ])
             .build()
             .unwrap();
 

crates/iceberg/src/spec/values/datum.rs

@@ -406,6 +406,12 @@ impl Datum {
             }
             PrimitiveType::Fixed(_) => PrimitiveLiteral::Binary(Vec::from(bytes)),
             PrimitiveType::Binary => PrimitiveLiteral::Binary(Vec::from(bytes)),
+            PrimitiveType::Variant => {
+                return Err(Error::new(
+                    ErrorKind::FeatureUnsupported,
+                    "Converting bytes to variant datum is not supported yet.",
+                ));
+            }
             PrimitiveType::Decimal { .. } => {
                 let unscaled_value = BigInt::from_signed_bytes_be(bytes);
                 PrimitiveLiteral::Int128(unscaled_value.to_i128().ok_or_else(|| {