Github user fhueske commented on a diff in the pull request:
https://github.com/apache/flink/pull/5927#discussion_r185932952
--- Diff:
flink-connectors/flink-connector-filesystem/src/main/java/org/apache/flink/streaming/connectors/fs/bucketing/BucketingSink.java
---
@@ -550,6 +550,9 @@ private void openNewPartFile(Path bucketPath,
BucketState<T> bucketState) throws
Path inProgressPath = getInProgressPathFor(partPath);
if (bucketState.writer == null) {
bucketState.writer = writerTemplate.duplicate();
+ if (bucketState.writer == null) {
+ throw new RuntimeException("Could not duplicate
writer.");
--- End diff --
I would add the class name of the `writerTemplate` object and that the
class needs to implement the `Writer.duplicate()` method.
---
