Protobuf generated classes should extend from Google::Protobuf::AbstractMessage

[andyw8]

Motivation

Problem reported in Shopify Core that to_proto wasn't being recognized.

Implementation

Mix in the necessary module.
Inherit from Google::Protobuf::AbstractMessage.

Tests

Updated.

[paracycle]

Hmm, I think we should instead make these classes subclass from Google::Protobuf::AbstractMessage instead, which pulls in this include as well: https://github.com/protocolbuffers/protobuf/blob/5d40c4f43409bbcdf7ab2d24cbb4b1c363cfa7a0/ruby/lib/google/protobuf/message_exts.rb#L29

It is a private constant, but since it will only be inside our generated RBI files, that shouldn't be a problem.

[paracycle]

Also, at runtime, that is the correct description of these message classes: https://github.com/protocolbuffers/protobuf/blob/5d40c4f43409bbcdf7ab2d24cbb4b1c363cfa7a0/ruby/lib/google/protobuf/ffi/message.rb#L35

[Morriar]

This change doesn't make a lot of sense. We would allow people to pass a superclass_name for a module constant and just silently drop it?

Instead you could do something like this:

root.create_path(constant) do |klass|
  raise unless klass.is_a?(RBI::Class)

  klass.superclass_name = "Google::Protobuf::AbstractMessage"
  # ...

[andyw8]

Updated with @Morriar's suggestion, but looking into the 1 failing test.

[andyw8]

Passing on Core.

[andyw8]

(merging this commit history was unintentional, I was used to the auto-squash in other repos).