feat: add equals_with_field_id method for RowType (#327)

crates/fluss/src/metadata/datatype.rs

@@ -979,6 +979,94 @@ impl RowType {
         ))
     }
 
+    /// Checks whether this RowType is equal to another, including field IDs.
+    ///
+    /// Unlike the standard `PartialEq` implementation, this method also compares
+    /// the field IDs of each field, not just the names and data types.
+    /// It also recursively checks nested RowTypes for equality including field IDs.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use fluss::metadata::{DataField, DataTypes, RowType};
+    ///
+    /// let fields1 = vec![
+    ///     DataField::new_with_field_id("id", DataTypes::int(), None, 0),
+    ///     DataField::new_with_field_id("name", DataTypes::string(), None, 1),
+    /// ];
+    /// let row_type1 = RowType::new(fields1);
+    ///
+    /// let fields2 = vec![
+    ///     DataField::new_with_field_id("id", DataTypes::int(), None, 0),
+    ///     DataField::new_with_field_id("name", DataTypes::string(), None, 1),
+    /// ];
+    /// let row_type2 = RowType::new(fields2);
+    ///
+    /// assert!(row_type1.equals_with_field_id(&row_type2));
+    ///
+    /// // Different field IDs
+    /// let fields3 = vec![
+    ///     DataField::new_with_field_id("id", DataTypes::int(), None, 0),
+    ///     DataField::new_with_field_id("name", DataTypes::string(), None, 2), // Different ID
+    /// ];
+    /// let row_type3 = RowType::new(fields3);
+    ///
+    /// assert!(!row_type1.equals_with_field_id(&row_type3));
+    /// ```
+    pub fn equals_with_field_id(&self, other: &RowType) -> bool {
+        // First check standard equality (nullable, field count, names, types)
+        if self.nullable != other.nullable || self.fields.len() != other.fields.len() {
+            return false;
+        }
+
+        // Check each field for equality including field_id
+        for (self_field, other_field) in self.fields.iter().zip(other.fields.iter()) {
+            if self_field.name != other_field.name
+                || self_field.field_id != other_field.field_id
+            {
+                return false;
+            }
+
+            // Recursively check data types for nested RowTypes
+            if !Self::data_type_equals_with_field_id(
+                &self_field.data_type,
+                &other_field.data_type,
+            ) {
+                return false;
+            }
+        }
+
+        true
+    }
+
+    /// Helper method to check if two DataTypes are equal, including field IDs for RowTypes.
+    fn data_type_equals_with_field_id(left: &DataType, right: &DataType) -> bool {
+        match (left, right) {
+            (DataType::Row(left_row), DataType::Row(right_row)) => {
+                left_row.equals_with_field_id(right_row)
+            }
+            (DataType::Array(left_arr), DataType::Array(right_arr)) => {
+                left_arr.nullable == right_arr.nullable
+                    && Self::data_type_equals_with_field_id(
+                        &left_arr.element_type,
+                        &right_arr.element_type,
+                    )
+            }
+            (DataType::Map(left_map), DataType::Map(right_map)) => {
+                left_map.nullable == right_map.nullable
+                    && Self::data_type_equals_with_field_id(
+                        &left_map.key_type,
+                        &right_map.key_type,
+                    )
+                    && Self::data_type_equals_with_field_id(
+                        &left_map.value_type,
+                        &right_map.value_type,
+                    )
+            }
+            _ => left == right,
+        }
+    }
+
     #[cfg(test)]
     pub fn with_data_types(data_types: Vec<DataType>) -> Self {
         let mut fields: Vec<DataField> = Vec::new();
@@ -1171,6 +1259,7 @@ pub struct DataField {
     pub name: String,
     pub data_type: DataType,
     pub description: Option<String>,
+    pub field_id: i32,
 }
 
 impl DataField {
@@ -1183,6 +1272,21 @@ impl DataField {
             name: name.into(),
             data_type,
             description,
+            field_id: -1,
+        }
+    }
+
+    pub fn new_with_field_id<N: Into<String>>(
+        name: N,
+        data_type: DataType,
+        description: Option<String>,
+        field_id: i32,
+    ) -> DataField {
+        DataField {
+            name: name.into(),
+            data_type,
+            description,
+            field_id,
         }
     }
 
@@ -1193,6 +1297,10 @@ impl DataField {
     pub fn data_type(&self) -> &DataType {
         &self.data_type
     }
+
+    pub fn field_id(&self) -> i32 {
+        self.field_id
+    }
 }
 
 impl Display for DataField {

crates/fluss/src/metadata/table.rs

@@ -250,10 +250,12 @@ impl SchemaBuilder {
 
         let data_fields = columns
             .iter()
-            .map(|c| DataField {
+            .enumerate()
+            .map(|(idx, c)| DataField {
                 name: c.name.clone(),
                 data_type: c.data_type.clone(),
                 description: c.comment.clone(),
+                field_id: idx as i32,
             })
             .collect();