Swift 4.1 migration

[NachoSoto]

Last updated and tested on: Xcode 9.3 GM.

Checklist

• Updated CHANGELOG.md.
• Remove BindingSource workarounds
• Make Signal.Event and ActionError Equatable
• .flatMap -> .compactMap
• Remove no longer necessary Result.materialize extension
• Wait for Xcode 9.3
• Update Travis
• Tag final Result release Can be done separately.
• Wait for fix to .logEvents regression -> Workaround is implemented, doesn't seem like they'll fix the regression.
• Maintain Swift 4.0.x compatibility using #if swift(>=4.1)
• Verify UnsafeMutablePointer deprecation changes (I'm not totally sure about them)

[andersio]

The where clauses for Error in Property.swift can be removed presumably.

[NachoSoto]

@andersio yup, done!

[NachoSoto]

Tested this on beta 2, tests still passing but the regression is still not fixed.

[NachoSoto]

I can't believe we need this workaround: 5bcb5e7 🤦‍♂️

[sharplet]

See also http://forums.swift.org/t/more-consistent-function-types/9765/1

[mishagray]

I'm seeing an issue with swift 4.1 compability and this PR:
#601

Basically.. all of my my 'signal.map { Int($0) }` is now resolving to a SignalProducer with a value that is a closure, and when I click on 'map' it resolves to the new map method from #601

Not sure how it behaves in swift 4.0, but swift 4.1 has issues. Not sure if this is just a bug in 9.3 beta 2.

[NachoSoto]

Interesting. Any chance you can provide a small test case for that? I can take a look, and maybe add it to the test suite.

[mishagray]

	let fetchImage = SignalProducer<UIImage, NoError>(value: UIImage())
	let optionalFetch = fetchImage.map { $0 as UIImage? }

	assert(optionalFetch is SignalProducer<UIImage?, NoError>, "did I get the right type?")


	let optionalFetch1: SignalProducer<UIImage?, NoError>  = fetchImage.map { $0 as UIImage? }
	let optionalFetch2: SignalProducer<(UIImage?) -> UIImage?, NoError>  = fetchImage.map { $0 as UIImage? }

So in swift 4.0 ... optionalFetch will be the expected type SignalProducer<UIImage?, NoError>. In swift 4.1 ... we get SignalProducer<(UIImage?) -> UIImage?, NoError>

Both of the 'optionalFetch1' and 'optionalFetch2' lines compile successfully in swift 4.1

[NachoSoto]

What happens if you do:

let optionalFetch2: SignalProducer<UIImage?, NoError>  = fetchImage.map { $0 as UIImage? }

[mishagray]

Ah... so this isn't NOT related to swift 4.1. I wrote that code above and got the same warning error on assertion line 'Cast from 'SignalProducer<(UIImage?) -> UIImage?, NoError>' to unrelated type 'SignalProducer<UIImage?, NoError>' always fails'

Every line compiles in swift 4.0/swift 4.1. I could just open this as in issue against #601. Since it's not actually realted to 4.1.

I just first saw it in my swift 4.1 branch, but I think it's unrelated to swift 4.1

[NachoSoto]

Ooooh yup, totally, it's related to #601, bad overload resolution :( Can you open an issue for that?
Thanks!

[mbuchetics]

What's the current status now that Xcode 9.3 and Swift 4.1 are officially released?

[NachoSoto]

I'm away for a month and won't be able to continue working on this, somebody else please pick it up from here? 😊

[mdiep]

The current ReactiveSwift release works with Xcode 9.3 / Swift 4.1. It just has some warnings.

[gunterhager]

Interesting. You're right, i've just tested it. It seems to work with Xcode 9.4/Swift 4.1.1 beta, too. Used to fail with older Xcode 9.3 betas.

[andersio]

@ikesyo any plan to release Result with Swift 4.1 soon?

[ikesyo]

@andersio Sorry for the delay, Result 4.0 has been released 🚢

https://github.com/antitypical/Result/releases/tag/4.0.0

[mdiep]

Do we want to maintain Xcode 9.2 / Swift 4.0.1 compatibility? As-is, this breaks compatibility (from changes I made) but retains some code for Swift <4.1. I'm not sure whether we should rip out the shims or add more in.

[andersio]

I am for supporting only Swift 4.1 given that we are going to bump the major version anyway.