NullPointerException in JsonStreamWriter.Builder::build caused by unspecified field mode #1419
Description
Steps to reproduce
Create a TableFieldSchema without specifying the Mode for the field's schema, then create a TableSchema containing that field, then create a JsonStreamWriter with that schema.
Code example
BigQueryWriteClient client = createClient();
String table = String.format("projects/%s/datasets/%s/tables/%s", project(), dataset(), table());
TableFieldSchema fieldSchema = TableFieldSchema.newBuilder()
.setName("f1")
.setType(TableFieldSchema.Type.STRING)
// If the line below is uncommented, no NPE is thrown
// .setMode(TableFieldSchema.Mode.NULLABLE)
.build();
TableSchema schema = TableSchema.newBuilder()
.addFields(fieldSchema)
.build();
JsonStreamWriter.newBuilder(table, schema, client).build();Stack trace
java.lang.NullPointerException
at com.google.protobuf.DescriptorProtos$FieldDescriptorProto$Builder.setLabel(DescriptorProtos.java:13430)
at com.google.cloud.bigquery.storage.v1.BQTableSchemaToProtoDescriptor.convertBQTableFieldToProtoField(BQTableSchemaToProtoDescriptor.java:150)
at com.google.cloud.bigquery.storage.v1.BQTableSchemaToProtoDescriptor.convertBQTableSchemaToProtoDescriptorImpl(BQTableSchemaToProtoDescriptor.java:113)
at com.google.cloud.bigquery.storage.v1.BQTableSchemaToProtoDescriptor.convertBQTableSchemaToProtoDescriptor(BQTableSchemaToProtoDescriptor.java:72)
at com.google.cloud.bigquery.storage.v1.JsonStreamWriter.<init>(JsonStreamWriter.java:62)
at com.google.cloud.bigquery.storage.v1.JsonStreamWriter.<init>(JsonStreamWriter.java:39)
at com.google.cloud.bigquery.storage.v1.JsonStreamWriter$Builder.build(JsonStreamWriter.java:333)
Any additional information below
Caused by a lookup of the BQTableSchemaModeMap map here with a key of TableFieldSchema.Mode.MODE_UNSPECIFIED, which is not included in the map's declaration here.
As a fix, it seems reasonable to either establish a default mode for these fields (I think NULLABLE is mentioned as the default here but not sure if that directly translates to desired behavior for the DDL API here), or fail to build a TableFieldSchema when no mode has been specified (unsure if this is possible with the code generation mechanism used for class, though). But anything that doesn't lead to an NPE would be nice :)