I've been looking at the following session from the 2019 Beam Summit
covering Schema-aware PCollections (18:00 -
https://www.youtube.com/watch?v=aRIZXtQiCHw). The specific part of the
video mentions that for fields accessed via the @FieldAccess annotation,
Beam checks for both the existence of the field AND matches the type during
pipeline construction time.
When trying this out on my application locally, I do see that Beam flags up
incorrectly specified fields that don't exist in the PCollection's schema.
However it seems as if it doesn't enforce/check the types of the parameter
variable match the types specified in the Schema.
For instance if I have a PCollection containing an attribute "field1" with
type String, when referring to this attribute in my DoFn using
*@FieldAccess("field1")
Double field1 *it does NOT flag this String/Double type mismatch during
pipeline construction similar to how it would do if I refer to an
attribute that doesn't exist in the schema.
Is this expected behaviour? If so, would there be any way in which I could
write a custom validator which strongly enforces @FieldAccess parameter
types against the types in the corresponding schema?
