Inconsistent handling of constant presence in groupSizeEncoding

[lukepalmer]

I'm new here, but believe I observe the following:

For the composite 'groupSizeEncoding' an encoder/decoder class will be generated, but not used. Code for handling the repeating group will be separately generated at point of usage based on the composite definition in the spec. This is, at least, confusing.

If the blockLength type interior to groupSizeEncoding is specified like:
<type name="blockLength" primitiveType="uint16" presence="constant">0</type>

The unused generated decoder will correctly implement the constant presence, but the point of usage code will ignore constant presence. The two copies of the code will have incompatible size and offsets. This seems incorrect.

Would it be accurate to say that constant presence for blockLength is not supported? If so, would it make sense for a specification like this to cause an error, rather than generating unexpected code?

[mjpt777]

Can you provide a worked example for what you are trying to achieve with this?