fix comments

hudi-client/hudi-client-common/src/main/java/org/apache/hudi/client/BaseHoodieWriteClient.java

@@ -39,6 +39,7 @@
 import org.apache.hudi.client.transaction.TransactionManager;
 import org.apache.hudi.client.utils.TransactionUtils;
 import org.apache.hudi.common.HoodiePendingRollbackInfo;
+import org.apache.hudi.common.config.HoodieCommonConfig;
 import org.apache.hudi.common.engine.HoodieEngineContext;
 import org.apache.hudi.common.model.HoodieCommitMetadata;
 import org.apache.hudi.common.model.HoodieFailedWritesCleaningPolicy;
@@ -276,7 +277,7 @@ private void saveInternalSchema(HoodieTable table, String instantTime, HoodieCom
     TableSchemaResolver schemaUtil = new TableSchemaResolver(table.getMetaClient());
     String historySchemaStr = schemaUtil.getTableHistorySchemaStrFromCommitMetadata().orElse("");
     FileBasedInternalSchemaStorageManager schemasManager = new FileBasedInternalSchemaStorageManager(table.getMetaClient());
-    if (!historySchemaStr.isEmpty() || Boolean.parseBoolean(config.getString("hoodie.datasource.write.reconcile.schema"))) {
+    if (!historySchemaStr.isEmpty() || Boolean.parseBoolean(config.getString(HoodieCommonConfig.RECONCILE_SCHEMA.key()))) {
       InternalSchema internalSchema;
       Schema avroSchema = HoodieAvroUtils.createHoodieWriteSchema(new Schema.Parser().parse(config.getSchema()));
       if (historySchemaStr.isEmpty()) {

hudi-common/src/main/java/org/apache/hudi/avro/HoodieAvroUtils.java

@@ -745,15 +745,18 @@ public static GenericRecord rewriteRecordWithNewSchema(IndexedRecord oldRecord,
    * b) For GenericRecord, copy over the data from the old schema to the new schema or set default values for all fields of this transformed schema
    *
    * @param oldRecord oldRecord to be rewritten
+   * @param oldAvroSchema old avro schema.
    * @param newSchema newSchema used to rewrite oldRecord
    * @param renameCols a map store all rename cols, (k, v)-> (colNameFromNewSchema, colNameFromOldSchema)
    * @param fieldNames track the full name of visited field when we travel new schema.
    * @return newRecord for new Schema
    */
-  private static Object rewriteRecordWithNewSchema(Object oldRecord, Schema oldSchema, Schema newSchema, Map<String, String> renameCols, Deque<String> fieldNames) {
+  private static Object rewriteRecordWithNewSchema(Object oldRecord, Schema oldAvroSchema, Schema newSchema, Map<String, String> renameCols, Deque<String> fieldNames) {
     if (oldRecord == null) {
       return null;
     }
+    // try to get real schema for union type
+    Schema oldSchema = getActualSchemaFromUnion(oldAvroSchema, oldRecord);
     switch (newSchema.getType()) {
       case RECORD:
         if (!(oldRecord instanceof IndexedRecord)) {
@@ -797,7 +800,7 @@ private static Object rewriteRecordWithNewSchema(Object oldRecord, Schema oldSch
         List<Object> newArray = new ArrayList();
         fieldNames.push("element");
         for (Object element : array) {
-          newArray.add(rewriteRecordWithNewSchema(element, getActualSchemaFromUnion(oldSchema.getElementType(), element), newSchema.getElementType(), renameCols, fieldNames));
+          newArray.add(rewriteRecordWithNewSchema(element, oldSchema.getElementType(), newSchema.getElementType(), renameCols, fieldNames));
         }
         fieldNames.pop();
         return newArray;
@@ -809,8 +812,7 @@ private static Object rewriteRecordWithNewSchema(Object oldRecord, Schema oldSch
         Map<Object, Object> newMap = new HashMap<>();
         fieldNames.push("value");
         for (Map.Entry<Object, Object> entry : map.entrySet()) {
-          newMap.put(entry.getKey(), rewriteRecordWithNewSchema(entry.getValue(),
-              getActualSchemaFromUnion(oldSchema.getValueType(), entry.getValue()), newSchema.getValueType(), renameCols, fieldNames));
+          newMap.put(entry.getKey(), rewriteRecordWithNewSchema(entry.getValue(), oldSchema.getValueType(), newSchema.getValueType(), renameCols, fieldNames));
         }
         fieldNames.pop();
         return newMap;

hudi-common/src/main/java/org/apache/hudi/common/config/HoodieCommonConfig.java

@@ -36,6 +36,13 @@ public class HoodieCommonConfig extends HoodieConfig {
       .defaultValue(false)
       .withDocumentation("Enables support for Schema Evolution feature");
 
+  public static final ConfigProperty<Boolean> RECONCILE_SCHEMA = ConfigProperty
+      .key("hoodie.datasource.write.reconcile.schema")
+      .defaultValue(false)
+      .withDocumentation("When a new batch of write has records with old schema, but latest table schema got "
+        + "evolved, this config will upgrade the records to leverage latest table schema(default values will be "
+        + "injected to missing fields). If not, the write batch would fail.");
+
   public static final ConfigProperty<ExternalSpillableMap.DiskMapType> SPILLABLE_DISK_MAP_TYPE = ConfigProperty
       .key("hoodie.common.spillable.diskmap.type")
       .defaultValue(ExternalSpillableMap.DiskMapType.BITCASK)

hudi-spark-datasource/hudi-spark-common/src/main/scala/org/apache/hudi/DataSourceOptions.scala

@@ -399,12 +399,7 @@ object DataSourceWriteOptions {
     .defaultValue(classOf[HiveSyncTool].getName)
     .withDocumentation("Sync tool class name used to sync to metastore. Defaults to Hive.")
 
-  val RECONCILE_SCHEMA: ConfigProperty[Boolean] = ConfigProperty
-    .key("hoodie.datasource.write.reconcile.schema")
-    .defaultValue(false)
-    .withDocumentation("When a new batch of write has records with old schema, but latest table schema got "
-      + "evolved, this config will upgrade the records to leverage latest table schema(default values will be "
-      + "injected to missing fields). If not, the write batch would fail.")
+  val RECONCILE_SCHEMA: ConfigProperty[Boolean] = HoodieCommonConfig.RECONCILE_SCHEMA
 
   // HIVE SYNC SPECIFIC CONFIGS
   // NOTE: DO NOT USE uppercase for the keys as they are internally lower-cased. Using upper-cases causes