regression: FileIO.writeDynamic() with side inputs fails in DirectRunner

When FileIO.writeDynamic is used with automatic sharding and  a Contextful.Fn that uses side inputs for the file naming, DirectRunner (and TestPipeline) fail with: 

java.lang.IllegalStateException: All PCollectionViews that are consumed must be written by some WriteView PTransform: Missing [<unnamed> [RunnerPCollectionView]]

Example code:  

PCollectionView<String> outputFileName =
   pipeline.apply(
      "outputDir",
       Create.of("/tmp/testout")).apply(View.asSingleton());

Contextful.Fn<String, FileIO.Write.FileNaming> manifestNaming =
   (element, c) ->
      (window, pane, numShards, shardIndex, compression) -> 
         c.sideInput(outputFileName)+shardIndex;

pipeline.apply(FileIO.<String, String>writeDynamic()
   .by(SerializableFunctions.constant(""))
   .withDestinationCoder(StringUtf8Coder.of())
   .via(TextIO.sink())
   .withTempDirectory("/tmp")
   .withNaming(Contextful.of(
      manifestNaming,
      Requirements.requiresSideInputs(outputFileName))));

This does not occur in Dataflow-runner

It does not occur if the ContextFul.Fn is not given side inputs.

It does not occur if withNumShards(1) is set.

It did not occur in 2.8.0, and does in 2.9.0 and 2.10.0-SNAPSHOT (as of today)

The cause appears to be due to the DirectRunner using TransformOverrides re-writing FileIO sinks to use runner-determined-sharding

( see DirectRunner.java line 226 )

 but I do not know why this started occuring in 2.9.0...