"breaking change" in json 2.9.1->2.10.0?

[bastelfreak]

Hi,
I'm one of the maintainers of https://github.com/voxpupuli/metadata-json-lint, where we validate a JSON file for the Puppet ecosystem. The relevant code (I think so, at least):

  # https://github.com/voxpupuli/metadata-json-lint/blob/03574807f8a7e05cfc22b48a86c25fd2137b5d75/lib/metadata_json_lint.rb#L103C1-L107C8
    begin
      parsed = JSON.parse(f)
    rescue Exception => e
      abort("Error: Unable to parse metadata.json: #{e.exception}")
    end

We've some tests in the module, they pass with json 2.9.1 and older. One of the tests assume the following error:

Error: Unable to parse metadata.json: unexpected token at '{
  "name": "puppetlabs-postgres'

With json 2.10.1 we get:

Error: Unable to parse metadata.json: expected ',' or '}' after object value, got: '"version": "3.4.1",
  "author": '

This could be considered as a breaking change, if we assume the output is even something like a stable/public API. Can you tell me if the rewording was intentional?

[byroot]

Yes it was intentional: #729

if we assume the output is even something like a stable/public API

It isn't. The exception class is, but the exception message is intended for humans and can change in any version. Heck, up until I fixed it a couple years ago, it was changing on every versions (#470). They're also not consistent between different implementations of the gem (Java, Pure, etc).

Also I have further plans to improve these messages, like including line a column numbers, so it might break again.

So it's probably best if your test only assume a specific error class, but doesn't try to match the message content.

[bastelfreak]

Thanks for clarification. I just removing matching for the exception text in our tests.