@propertyWrapper Published

[beastgrim]

Hello! I've implemented this interface. That allows use construction like this:
@Published var value: String?
And bind and subscribe:
$value.assign(to: \.text, on: textLabel)
I hope that will be helpful.

[OpenCombineBot]

LGTM

Generated by 🚫 Danger Swift against a2903f0

[broadwaylamb]

Thank you!

I've added some comments, but in order for it to be merged we'll need tests, also can you please address the bot's comments? :)

[beastgrim]

Sorry for inconvenience. It is first time when I do pull request to GitHub. I fixed all comments and also warnings from SwiftLint. It remains only to write tests.
When it is done what I should do next? Should I close this pull request and open another or there is another variants? Thanks!

[broadwaylamb]

It is first time when I do pull request to GitHub

I’m flattered!

Should I close this pull request and open another or there is another variants?

When you write the tests, commit them to this branch, it is better if they come along with the feature that they test. No need to create a separate pull request for that :)

[broadwaylamb]

Can you please remove the interface of Published from the RemainingCombineInterface.swift so that we can track what's implemented and what's not?

I also see that your implementation lacks this subscript. Implementing it is non-trivial, so I suggest to add a stub marked as unavailable:

@available(*, unavailable, message: "This subscript is unavailable in OpenCombine yet")
public static subscript<EnclosingSelf: AnyObject>(
    _enclosingInstance object: EnclosingSelf,
    wrapped wrappedKeyPath: ReferenceWritableKeyPath<EnclosingSelf, Value>,
    storage storageKeyPath: ReferenceWritableKeyPath<EnclosingSelf, Published<Value>>
) -> Value {
    get { fatalError() }
    set { fatalError() }
}

[beastgrim]

I also see that your implementation lacks this subscript. Implementing it is non-trivial, so I suggest to add a stub marked as unavailable:

@available(*, unavailable, message: "This subscript is unavailable in OpenCombine yet")
public static subscript<EnclosingSelf: AnyObject>(
    _enclosingInstance object: EnclosingSelf,
    wrapped wrappedKeyPath: ReferenceWritableKeyPath<EnclosingSelf, Value>,
    storage storageKeyPath: ReferenceWritableKeyPath<EnclosingSelf, Published<Value>>
) -> Value {
    get { fatalError() }
    set { fatalError() }
}

I've added this subscript, but I didn't find that implementation in Apple Combine framework (Xcode 11.0 beta 6). I will be grateful If you give me more information about that functionality and how I can use that. Thanks!

[codecov]

Codecov Report

Merging #52 into master will increase coverage by 0.18%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master      #52      +/-   ##
==========================================
+ Coverage   97.55%   97.74%   +0.18%     
==========================================
  Files          42       43       +1     
  Lines        1679     1727      +48     
==========================================
+ Hits         1638     1688      +50     
+ Misses         41       39       -2

Impacted Files	Coverage Δ
...enCombine/Publishers/Publishers.ReplaceError.swift	100% <0%> (ø)
...rces/OpenCombine/Publishers/Publishers.Print.swift	98.36% <0%> (+3.27%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
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[codecov]

Codecov Report

Merging #52 into master will increase coverage by 0.18%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master      #52      +/-   ##
==========================================
+ Coverage   97.55%   97.74%   +0.18%     
==========================================
  Files          42       43       +1     
  Lines        1679     1727      +48     
==========================================
+ Hits         1638     1688      +50     
+ Misses         41       39       -2

Impacted Files	Coverage Δ
...enCombine/Publishers/Publishers.ReplaceError.swift	100% <0%> (ø)
...rces/OpenCombine/Publishers/Publishers.Print.swift	98.36% <0%> (+3.27%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 9b9915b...95fd4ed. Read the comment docs.

[broadwaylamb]

@beastgrim sure.

This is used for accessing the object that has its property wrapped in @Published. You can find how it can be used here.

You may wonder why I said it's non-trivial. The answer is that you will somehow need to provide a default implementation for the objectWillChange property of the ObservableObject protocol. According to Apple engineers, that requires asking the Swift runtime for class metadata.

[broadwaylamb]

Thanks! This looks good to me. Are you up to write some tests? I could write them myself if you don’t feel like it.

We also have our CI failing, but that’s not your fault, it just needs to be updated for the newest Swift version.

[beastgrim]

I can write tests for Published but before I would like complete all in Published functionality. There is one property that doesn't exist now "objectWillChange"

▿ Combine.Published<Swift.String>
  - value: "test"
  - publisher: nil
  - objectWillChange: nil

So I'm going make some investigation how and when this "objectWillChange" uses in Combine framework and after that finish code in "Published" struct. And then cover all code with tests.

I also do not mind if you confirm this pull request. And I will make all these things in another pull request. As it suits you best.

[broadwaylamb]

I’ve already investigated it and have a prototype implementation :)

This objectWillChange thing is related to the ObservableObject protocol and involves some low-level stuff, so we’d need to implement ObservableObject first. It doesn’t affect the behavior of Published right now anyway, so it will be okay if you write the tests for what’s already done and I’ll merge this PR.

But if you’d really like to try to make it, you can take a look at this library and this doc on type metadata.

[beastgrim]

I could not come up with tests for "Published", this is more like a template for tests. Sorry 😐

[broadwaylamb]

So I've just merged #54, can I ask you to synchronize with the master branch?

[broadwaylamb]

Thank you for your contribution, @beastgrim!