Fixes #1617: Federation Enum not parsing value 0

[ShadyKutz]

Fixes #1617

Updated buildSchemaFromSDL to handle enums with a value of 0. Previously, when an enum had a value of 0, the name would be used as the enum value.

Added a unit test to ensure 0 is parsed correctly.

TODO:

• Update CHANGELOG.md* with your change (include reference to issue & this PR)
• Make sure all of the significant new logic is covered by tests
• Rebase your changes on master so that they can be merged easily
• Make sure all tests and linter rules pass

[apollo-cla]

@postman-nz: Thank you for submitting a pull request! Before we can merge it, you'll need to sign the Apollo Contributor License Agreement here: https://contribute.apollographql.com/

[ShadyKutz]

I'm working on the CLA, just need to confirm with my employer that it's ok to sign.

[marjorg]

@postman-nz We ran into the same issue with our Federations, did you get around to signing the CLA so the PR can proceed?

[ShadyKutz]

@marjorg Yes I have signed the CLA, and completed all the requirements for the PR to pass.

As a workaround, we hard coded all our 0 enum values to -1 (assuming -1 isn't being used), and in our resolvers added a check:
if(model.enumValue == 0) model.enumValue = -1

Which works for now, but it's not a long term solution.

[lilyball]

I have no context here but the fix looks straightforward.

[ShadyKutz]

Hi @JakeDawkins and @jbaxleyiii,

Is there anything else I have to do to get this PR completed? (I'm new to contributing to public repos, so not 100% sure on the process)

Thanks!

[JakeDawkins]

Hey @postman-nz! So sorry for letting this slip through the cracks. Everything looks good to me! Can you rebase this branch off master? My Update Branch button isn't working for some reason 🤔

[ShadyKutz]

Hey @postman-nz! So sorry for letting this slip through the cracks. Everything looks good to me! Can you rebase this branch off master? My Update Branch button isn't working for some reason 🤔

No problem mate! I have rebased with master (I hope 😄). Let me know if there is anything else you'd like me to do.