Spark 4.1: Initial support for MERGE INTO schema evolution

spark/v4.1/spark-extensions/src/test/java/org/apache/iceberg/spark/extensions/TestMergeSchemaEvolution.java

@@ -0,0 +1,227 @@
+/*
+ * 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.spark.extensions;
+
+import static org.apache.spark.sql.functions.col;
+import static org.assertj.core.api.Assumptions.assumeThat;
+
+import java.util.Map;
+import org.apache.iceberg.ParameterizedTestExtension;
+import org.apache.iceberg.relocated.com.google.common.collect.ImmutableList;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.TestTemplate;
+import org.junit.jupiter.api.extension.ExtendWith;
+
+@ExtendWith(ParameterizedTestExtension.class)
+public class TestMergeSchemaEvolution extends SparkRowLevelOperationsTestBase {
+
+  @BeforeAll
+  public static void setupSparkConf() {
+    spark.conf().set("spark.sql.shuffle.partitions", "4");
+  }
+
+  @AfterEach
+  public void removeTables() {
+    sql("DROP TABLE IF EXISTS %s", tableName);
+    sql("DROP TABLE IF EXISTS source");
+  }
+
+  @TestTemplate
+  public void testMergeWithSchemaEvolutionSourceHasMoreColumns() {
+    assumeThat(branch).as("Schema evolution does not work for branches currently").isNull();
+
+    createAndInitTable(
+        "id INT, dep STRING",
+        "{ \"id\": 1, \"dep\": \"hr\" }\n" + "{ \"id\": 2, \"dep\": \"software\" }");
+
+    createOrReplaceView(
+        "source",
+        "id INT, dep STRING, salary INT",
+        "{ \"id\": 1, \"dep\": \"hr\", \"salary\": 100 }\n"
+            + "{ \"id\": 3, \"dep\": \"finance\", \"salary\": 300 }");
+
+    sql(
+        "MERGE WITH SCHEMA EVOLUTION INTO %s AS t USING source AS s "
+            + "ON t.id == s.id "
+            + "WHEN MATCHED THEN "
+            + "  UPDATE SET * "
+            + "WHEN NOT MATCHED THEN "
+            + "  INSERT *",
+        commitTarget());
+
+    // The new 'salary' column should be added to the target table
+    ImmutableList<Object[]> expectedRows =
+        ImmutableList.of(
+            row(1, "hr", 100), // updated with salary
+            row(2, "software", null), // kept, salary is null
+            row(3, "finance", 300)); // new row with salary
+    assertEquals(
+        "Should have expected rows with new column",
+        expectedRows,
+        sql("SELECT id, dep, salary FROM %s ORDER BY id", selectTarget()));
+  }
+
+  @TestTemplate
+  public void testMergeWithSchemaEvolutionSourceHasFewerColumns() {
+    assumeThat(branch).as("Schema evolution does not work for branches currently").isNull();
+
+    createAndInitTable(
+        "id INT, dep STRING, salary INT",
+        "{ \"id\": 1, \"dep\": \"hr\", \"salary\": 100 }\n"
+            + "{ \"id\": 2, \"dep\": \"software\", \"salary\": 200 }");
+
+    createOrReplaceView(
+        "source",
+        "id INT, dep STRING",
+        "{ \"id\": 1, \"dep\": \"hr-updated\" }\n" + "{ \"id\": 3, \"dep\": \"finance\" }");
+
+    sql(
+        "MERGE WITH SCHEMA EVOLUTION INTO %s AS t USING source AS s "
+            + "ON t.id == s.id "
+            + "WHEN MATCHED THEN "
+            + "  UPDATE SET * "
+            + "WHEN NOT MATCHED THEN "
+            + "  INSERT *",
+        commitTarget());
+
+    // Rows should have null for missing salary column from source
+    ImmutableList<Object[]> expectedRows =
+        ImmutableList.of(
+            row(1, "hr-updated", 100), // updated, salary retains value
+            row(2, "software", 200), // kept
+            row(3, "finance", null)); // new row, salary is null
+    assertEquals(
+        "Should have expected rows",
+        expectedRows,
+        sql("SELECT id, dep, salary FROM %s ORDER BY id", selectTarget()));
+  }
+
+  @TestTemplate
+  public void testMergeWithSchemaEvolutionUsingDataFrameApi() {
+    assumeThat(branch).as("Schema evolution does not work for branches currently").isNull();
+
+    createAndInitTable(
+        "id INT, dep STRING",
+        "{ \"id\": 1, \"dep\": \"hr\" }\n" + "{ \"id\": 2, \"dep\": \"software\" }");
+
+    createOrReplaceView(
+        "source",
+        "id INT, dep STRING, salary INT",
+        "{ \"id\": 1, \"dep\": \"hr-updated\", \"salary\": 100 }\n"
+            + "{ \"id\": 3, \"dep\": \"finance\", \"salary\": 300 }");
+
+    spark
+        .table("source")
+        .mergeInto(commitTarget(), col(commitTarget() + ".id").equalTo(col("source.id")))
+        .whenMatched()
+        .updateAll()
+        .whenNotMatched()
+        .insertAll()
+        .withSchemaEvolution()
+        .merge();
+
+    // The new 'salary' column should be added
+    ImmutableList<Object[]> expectedRows =
+        ImmutableList.of(
+            row(1, "hr-updated", 100), // updated
+            row(2, "software", null), // kept
+            row(3, "finance", 300)); // new
+    assertEquals(
+        "Should have expected rows with schema evolution via DataFrame API",
+        expectedRows,
+        sql("SELECT id, dep, salary FROM %s ORDER BY id", selectTarget()));
+  }
+
+  @TestTemplate
+  public void testMergeWithSchemaEvolutionNestedStruct() {
+    assumeThat(branch).as("Schema evolution does not work for branches currently").isNull();
+
+    createAndInitTable(
+        "id INT, s STRUCT<c1:INT,c2:STRING>",
+        "{ \"id\": 1, \"s\": { \"c1\": 10, \"c2\": \"a\" } }\n"
+            + "{ \"id\": 2, \"s\": { \"c1\": 20, \"c2\": \"b\" } }");
+
+    createOrReplaceView(
+        "source",
+        "id INT, s STRUCT<c1:INT,c2:STRING,c3:INT>",
+        "{ \"id\": 1, \"s\": { \"c1\": 100, \"c2\": \"aa\", \"c3\": 1000 } }\n"
+            + "{ \"id\": 3, \"s\": { \"c1\": 300, \"c2\": \"cc\", \"c3\": 3000 } }");
+
+    sql(
+        "MERGE WITH SCHEMA EVOLUTION INTO %s AS t USING source AS s "
+            + "ON t.id == s.id "
+            + "WHEN MATCHED THEN "
+            + "  UPDATE SET * "
+            + "WHEN NOT MATCHED THEN "
+            + "  INSERT *",
+        commitTarget());
+
+    // The nested struct should have the new c3 field
+    ImmutableList<Object[]> expectedRows =
+        ImmutableList.of(
+            row(1, row(100, "aa", 1000)), // updated with nested field
+            row(2, row(20, "b", null)), // kept, c3 is null
+            row(3, row(300, "cc", 3000))); // new
+    assertEquals(
+        "Should have expected rows with nested struct evolution",
+        expectedRows,
+        sql("SELECT id, s FROM %s ORDER BY id", selectTarget()));
+  }
+
+  @TestTemplate
+  public void testMergeWithSchemaEvolutionTypeWidening() {
+    assumeThat(branch).as("Schema evolution does not work for branches currently").isNull();
+
+    // Target has INT column
+    createAndInitTable(
+        "id INT, value INT", "{ \"id\": 1, \"value\": 100 }\n" + "{ \"id\": 2, \"value\": 200 }");
+
+    // Source has LONG column - should widen INT to LONG
+    createOrReplaceView(
+        "source",
+        "id INT, value LONG",
+        "{ \"id\": 1, \"value\": 1000000000000 }\n" + "{ \"id\": 3, \"value\": 3000000000000 }");
+
+    sql(
+        "MERGE WITH SCHEMA EVOLUTION INTO %s AS t USING source AS s "
+            + "ON t.id == s.id "
+            + "WHEN MATCHED THEN "
+            + "  UPDATE SET * "
+            + "WHEN NOT MATCHED THEN "
+            + "  INSERT *",
+        commitTarget());
+
+    // The 'value' column should be widened from INT to LONG
+    ImmutableList<Object[]> expectedRows =
+        ImmutableList.of(
+            row(1, 1000000000000L), // updated with long value
+            row(2, 200L), // kept, value promoted to long
+            row(3, 3000000000000L)); // new row with long value
+    assertEquals(
+        "Should have expected rows with type widening",
+        expectedRows,
+        sql("SELECT id, value FROM %s ORDER BY id", selectTarget()));
+  }
+
+  @Override
+  protected Map<String, String> extraTableProperties() {
+    return Map.of();
+  }
+}

spark/v4.1/spark/src/main/java/org/apache/iceberg/spark/source/SparkTable.java

@@ -106,6 +106,7 @@ public class SparkTable
           "identifier-fields");
   private static final Set<TableCapability> CAPABILITIES =
       ImmutableSet.of(
+          TableCapability.AUTOMATIC_SCHEMA_EVOLUTION,
           TableCapability.BATCH_READ,
           TableCapability.BATCH_WRITE,
           TableCapability.MICRO_BATCH_READ,