Flink: Project the RowData to remove meta-columns

api/src/main/java/org/apache/iceberg/util/StructProjection.java

@@ -155,6 +155,12 @@ public int size() {
 
   @Override
   public <T> T get(int pos, Class<T> javaClass) {
+    if (struct == null) {
+      // Return a null struct when projecting a nested required field from an optional struct.
+      // More details can see issue #2738.
+      return null;
+    }
+
     int structPos = positionMap[pos];
 
     if (nestedProjections[pos] != null) {

flink/src/main/java/org/apache/iceberg/flink/data/RowDataProjection.java

@@ -0,0 +1,240 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.iceberg.flink.data;
+
+import java.util.Map;
+import org.apache.flink.table.data.ArrayData;
+import org.apache.flink.table.data.DecimalData;
+import org.apache.flink.table.data.MapData;
+import org.apache.flink.table.data.RawValueData;
+import org.apache.flink.table.data.RowData;
+import org.apache.flink.table.data.StringData;
+import org.apache.flink.table.data.TimestampData;
+import org.apache.flink.table.types.logical.RowType;
+import org.apache.flink.types.RowKind;
+import org.apache.iceberg.Schema;
+import org.apache.iceberg.flink.FlinkSchemaUtil;
+import org.apache.iceberg.relocated.com.google.common.base.Preconditions;
+import org.apache.iceberg.relocated.com.google.common.collect.Maps;
+import org.apache.iceberg.types.Types;
+
+public class RowDataProjection implements RowData {
+  /**
+   * Creates a projecting wrapper for {@link RowData} rows.
+   * <p>
+   * This projection does not work with repeated types like lists and maps.
+   *
+   * @param schema schema of rows wrapped by this projection
+   * @param projectedSchema result schema of the projected rows
+   * @return a wrapper to project rows
+   */
+  public static RowDataProjection create(Schema schema, Schema projectedSchema) {
+    return RowDataProjection.create(FlinkSchemaUtil.convert(schema), schema.asStruct(), projectedSchema.asStruct());
+  }
+
+  /**
+   * Creates a projecting wrapper for {@link RowData} rows.
+   * <p>
+   * This projection does not work with repeated types like lists and maps.
+   *
+   * @param rowType flink row type of rows wrapped by this projection
+   * @param schema schema of rows wrapped by this projection
+   * @param projectedSchema result schema of the projected rows
+   * @return a wrapper to project rows
+   */
+  public static RowDataProjection create(RowType rowType, Types.StructType schema, Types.StructType projectedSchema) {
+    return new RowDataProjection(rowType, schema, projectedSchema);
+  }
+
+  private final RowData.FieldGetter[] getters;
+  private RowData rowData;
+
+  private RowDataProjection(RowType rowType, Types.StructType rowStruct, Types.StructType projectType) {
+    Map<Integer, Integer> fieldIdToPosition = Maps.newHashMap();
+    for (int i = 0; i < rowStruct.fields().size(); i++) {
+      fieldIdToPosition.put(rowStruct.fields().get(i).fieldId(), i);
+    }
+
+    this.getters = new RowData.FieldGetter[projectType.fields().size()];
+    for (int i = 0; i < getters.length; i++) {
+      Types.NestedField projectField = projectType.fields().get(i);
+      Types.NestedField rowField = rowStruct.field(projectField.fieldId());
+      if (rowField == null) {
+        throw new IllegalArgumentException(String.format(
+            "Cannot locate the project field <%s> in the iceberg struct <%s>", projectField, rowStruct));
+      }
+
+      getters[i] = createFieldGetter(rowType, fieldIdToPosition.get(projectField.fieldId()), rowField, projectField);
+    }
+  }
+
+  private static RowData.FieldGetter createFieldGetter(RowType rowType,
+                                                       int position,
+                                                       Types.NestedField rowField,
+                                                       Types.NestedField projectField) {
+    Preconditions.checkArgument(rowField.type().typeId() == projectField.type().typeId(),
+        "Different iceberg type between row field <%s> and project field <%s>", rowField, projectField);
+
+    switch (projectField.type().typeId()) {
+      case STRUCT:
+        RowType nestedRowType = (RowType) rowType.getTypeAt(position);
+        return row -> {
+          RowData nestedRow = row.isNullAt(position) ? null : row.getRow(position, nestedRowType.getFieldCount());
+          return RowDataProjection
+              .create(nestedRowType, rowField.type().asStructType(), projectField.type().asStructType())
+              .wrap(nestedRow);
+        };
+
+      case MAP:
+        Types.MapType projectedMap = projectField.type().asMapType();
+        Types.MapType originalMap = rowField.type().asMapType();
+
+        boolean keyProjectable = !projectedMap.keyType().isNestedType() ||
+            projectedMap.keyType().equals(originalMap.keyType());
+        boolean valueProjectable = !projectedMap.valueType().isNestedType() ||
+            projectedMap.valueType().equals(originalMap.valueType());
+        Preconditions.checkArgument(keyProjectable && valueProjectable,
+            "Cannot project a partial map key or value with non-primitive type. Trying to project <%s> out of <%s>",
+            projectField, rowField);
+
+        return RowData.createFieldGetter(rowType.getTypeAt(position), position);
+
+      case LIST:
+        Types.ListType projectedList = projectField.type().asListType();
+        Types.ListType originalList = rowField.type().asListType();
+
+        boolean elementProjectable = !projectedList.elementType().isNestedType() ||
+            projectedList.elementType().equals(originalList.elementType());
+        Preconditions.checkArgument(elementProjectable,
+            "Cannot project a partial list element with non-primitive type. Trying to project <%s> out of <%s>",
+            projectField, rowField);
+
+        return RowData.createFieldGetter(rowType.getTypeAt(position), position);
+
+      default:
+        return RowData.createFieldGetter(rowType.getTypeAt(position), position);
+    }
+  }
+
+  public RowData wrap(RowData row) {
+    this.rowData = row;
+    return this;
+  }
+
+  private Object getValue(int pos) {
+    return getters[pos].getFieldOrNull(rowData);
+  }
+
+  @Override
+  public int getArity() {
+    return getters.length;
+  }
+
+  @Override
+  public RowKind getRowKind() {
+    return rowData.getRowKind();
+  }
+
+  @Override
+  public void setRowKind(RowKind kind) {
+    throw new UnsupportedOperationException("Cannot set row kind in the RowDataProjection");
+  }
+
+  @Override
+  public boolean isNullAt(int pos) {
+    return rowData == null || getValue(pos) == null;
+  }
+
+  @Override
+  public boolean getBoolean(int pos) {
+    return (boolean) getValue(pos);
+  }
+
+  @Override
+  public byte getByte(int pos) {
+    return (byte) getValue(pos);
+  }
+
+  @Override
+  public short getShort(int pos) {
+    return (short) getValue(pos);
+  }
+
+  @Override
+  public int getInt(int pos) {
+    return (int) getValue(pos);
+  }
+
+  @Override
+  public long getLong(int pos) {
+    return (long) getValue(pos);
+  }
+
+  @Override
+  public float getFloat(int pos) {
+    return (float) getValue(pos);
+  }
+
+  @Override
+  public double getDouble(int pos) {
+    return (double) getValue(pos);
+  }
+
+  @Override
+  public StringData getString(int pos) {
+    return (StringData) getValue(pos);
+  }
+
+  @Override
+  public DecimalData getDecimal(int pos, int precision, int scale) {
+    return (DecimalData) getValue(pos);
+  }
+
+  @Override
+  public TimestampData getTimestamp(int pos, int precision) {
+    return (TimestampData) getValue(pos);
+  }
+
+  @Override
+  @SuppressWarnings("unchecked")
+  public <T> RawValueData<T> getRawValue(int pos) {
+    return (RawValueData<T>) getValue(pos);
+  }
+
+  @Override
+  public byte[] getBinary(int pos) {
+    return (byte[]) getValue(pos);
+  }
+
+  @Override
+  public ArrayData getArray(int pos) {
+    return (ArrayData) getValue(pos);
+  }
+
+  @Override
+  public MapData getMap(int pos) {
+    return (MapData) getValue(pos);
+  }
+
+  @Override
+  public RowData getRow(int pos, int numFields) {
+    return (RowData) getValue(pos);
+  }
+}

flink/src/main/java/org/apache/iceberg/flink/source/RowDataFileScanTaskReader.java

@@ -22,6 +22,7 @@
 import java.util.Map;
 import org.apache.flink.annotation.Internal;
 import org.apache.flink.table.data.RowData;
+import org.apache.flink.table.types.logical.RowType;
 import org.apache.iceberg.FileScanTask;
 import org.apache.iceberg.MetadataColumns;
 import org.apache.iceberg.Schema;
@@ -34,6 +35,7 @@
 import org.apache.iceberg.flink.data.FlinkAvroReader;
 import org.apache.iceberg.flink.data.FlinkOrcReader;
 import org.apache.iceberg.flink.data.FlinkParquetReaders;
+import org.apache.iceberg.flink.data.RowDataProjection;
 import org.apache.iceberg.flink.data.RowDataUtil;
 import org.apache.iceberg.io.CloseableIterable;
 import org.apache.iceberg.io.CloseableIterator;
@@ -70,9 +72,18 @@ public CloseableIterator<RowData> open(FileScanTask task, InputFilesDecryptor in
         PartitionUtil.constantsMap(task, RowDataUtil::convertConstant);
 
     FlinkDeleteFilter deletes = new FlinkDeleteFilter(task, tableSchema, projectedSchema, inputFilesDecryptor);
-    return deletes
-        .filter(newIterable(task, deletes.requiredSchema(), idToConstant, inputFilesDecryptor))
-        .iterator();
+    CloseableIterable<RowData> iterable = deletes.filter(
+        newIterable(task, deletes.requiredSchema(), idToConstant, inputFilesDecryptor)
+    );
+
+    // Project the RowData to remove the extra meta columns.
+    if (!projectedSchema.sameSchema(deletes.requiredSchema())) {
+      RowDataProjection rowDataProjection = RowDataProjection.create(
+          deletes.requiredRowType(), deletes.requiredSchema().asStruct(), projectedSchema.asStruct());
+      iterable = CloseableIterable.transform(iterable, rowDataProjection::wrap);
+    }
+
+    return iterable.iterator();
   }
 
   private CloseableIterable<RowData> newIterable(
@@ -156,16 +167,22 @@ private CloseableIterable<RowData> newOrcIterable(
   }
 
   private static class FlinkDeleteFilter extends DeleteFilter<RowData> {
+    private final RowType requiredRowType;
     private final RowDataWrapper asStructLike;
     private final InputFilesDecryptor inputFilesDecryptor;
 
     FlinkDeleteFilter(FileScanTask task, Schema tableSchema, Schema requestedSchema,
                       InputFilesDecryptor inputFilesDecryptor) {
       super(task, tableSchema, requestedSchema);
-      this.asStructLike = new RowDataWrapper(FlinkSchemaUtil.convert(requiredSchema()), requiredSchema().asStruct());
+      this.requiredRowType = FlinkSchemaUtil.convert(requiredSchema());
+      this.asStructLike = new RowDataWrapper(requiredRowType, requiredSchema().asStruct());
       this.inputFilesDecryptor = inputFilesDecryptor;
     }
 
+    public RowType requiredRowType() {
+      return requiredRowType;
+    }
+
     @Override
     protected StructLike asStructLike(RowData row) {
       return asStructLike.wrap(row);