deferred.fulfill for a Promise<Void> has issue with latest PMK, Swift4 & Xcode 9

[dgaedcke]

Problem with your promises implementation....for the latest PromiseKit
for a Promise{Void}, you are generating:
deferred.fulfill( )
when you should generate
deferred.fulfill( () )
Note the extra parens as the void arg

[wing328]

@dgaedcke do you mind submitting a PR so that we review the fix more easily?

[dgaedcke]

My understanding of PR is that I would submit a proposed code fix and ask you to merge it in? I understand the basics of creating a PR on Github, but I have no clue how to find the right place in your code to propose the fix. All I can say is that for the latest PMK, whatever template generates:
deferred.fulfill( )
should instead generate:
deferred.fulfill( () ) // void parens

I've been fixing my generated code manually to keep the compiler happy.

[wing328]

https://github.com/swagger-api/swagger-codegen/blob/master/modules/swagger-codegen/src/main/resources/swift4/api.mustache#L59 should be the line to fix it.

You will need to do something like:

{{^returnType}}(){{/returnType}}

[wing328]

cc @jgavris @ehyche @Edubits @jaz-ah

[dgaedcke]

That would work great if EVERY pmk.fulfill expected a void argument.
But that's not the case so I can't replace "data!" with "()" or I'd break those other (more common) use-cases. I suppose I could add some if-else logic but I really don't know what to test for in "data!" and I'm certain my hacking will be more trouble to you than it's worth....