PARQUET-2069: Allow list and array record types to be compatible.

parquet-avro/src/main/java/org/apache/parquet/avro/AvroReadSupport.java

@@ -25,8 +25,10 @@
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.util.ReflectionUtils;
 import org.apache.parquet.hadoop.api.ReadSupport;
+import org.apache.parquet.io.InvalidRecordException;
 import org.apache.parquet.io.api.RecordMaterializer;
 import org.apache.parquet.schema.MessageType;
+import org.apache.log4j.Logger;
 
 /**
  * Avro implementation of {@link ReadSupport} for avro generic, specific, and
@@ -36,6 +38,7 @@
  * @param <T> the Java type of records created by this ReadSupport
  */
 public class AvroReadSupport<T> extends ReadSupport<T> {
+  static Logger log = Logger.getLogger(AvroReadSupport.class.getName());  
 
   public static String AVRO_REQUESTED_PROJECTION = "parquet.avro.projection";
   private static final String AVRO_READ_SCHEMA = "parquet.avro.read.schema";
@@ -136,10 +139,22 @@ public RecordMaterializer<T> prepareForRead(
 
     GenericData model = getDataModel(configuration);
     String compatEnabled = metadata.get(AvroReadSupport.AVRO_COMPATIBILITY);
-    if (compatEnabled != null && Boolean.valueOf(compatEnabled)) {
-      return newCompatMaterializer(parquetSchema, avroSchema, model);
+
+    try {
+      if (compatEnabled != null && Boolean.valueOf(compatEnabled)) {
+        return newCompatMaterializer(parquetSchema, avroSchema, model);
+      }
+      return new AvroRecordMaterializer<T>(parquetSchema, avroSchema, model);
+    } catch (InvalidRecordException | ClassCastException e) {
+      log.error("Warning, Avro schema doesn't match Parquet schema, falling back to conversion: ", e);
+      // If the Avro schema is bad, fall back to reconstructing it from the Parquet schema
+      avroSchema = new AvroSchemaConverter(configuration).convert(parquetSchema);
+
+      if (compatEnabled != null && Boolean.valueOf(compatEnabled)) {
+        return newCompatMaterializer(parquetSchema, avroSchema, model);
+      }
+      return new AvroRecordMaterializer<T>(parquetSchema, avroSchema, model);
     }
-    return new AvroRecordMaterializer<T>(parquetSchema, avroSchema, model);
   }
 
   @SuppressWarnings("unchecked")

parquet-avro/src/test/java/org/apache/parquet/avro/TestArrayListCompatibility.java

@@ -0,0 +1,46 @@
+/**
+ * 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.parquet.avro;
+
+import com.google.common.io.Resources;
+import org.apache.avro.generic.GenericData;
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.Path;
+import org.apache.parquet.hadoop.ParquetReader;
+import org.junit.Test;
+import java.io.IOException;
+
+public class TestArrayListCompatibility {
+
+  @Test
+  public void testListArrayCompatibility() throws IOException {
+    Path testPath = new Path(Resources.getResource("list-array-compat.parquet").getFile());
+
+    Configuration conf = new Configuration();
+    ParquetReader<Object> parquetReader =
+      AvroParquetReader.builder(testPath).withConf(conf).build();
+    GenericData.Record firstRecord;
+    firstRecord = (GenericData.Record) parquetReader.read();
+    if (firstRecord == null) {
+      throw new IOException("Can't process empty Parquet file");
+    }
+    firstRecord.getSchema().toString(true);
+  }
+
+}