Testers wanted: Store "core" beta

[stephencelis]

👋

Hey all, we would love to get some early eyes on a branch we've been working on that revamps the internals driving the Store, which we are calling core: #3460

Our goals:

• Improve store performance, especially scoped stores.
• Set up an infrastructure that will unlock future functionality for TCA 2.0, including non-main actor stores and other new reducer features that aren't currently possible.

Ideally this is a fully backwards-compatible release, so you can point your up-to-date TCA application to the following and hopefully everything just works:

branch: "core"

Please report feedback to us! We don't want such a major refactor to have downstream effects on your production applications, so let's catch any issues early 🤠

[jshier]

I'm getting deprecation warnings about writable key paths when using destination enums:

.sheet(item: $store.scope(state: \.destination?.uploadPhoto, action: \.destination.uploadPhoto))

[jshier]

Otherwise the app works fine.

[stephencelis]

Thanks for the report! We've reverted that deprecation to reconsider its implications.

[brzzdev]

I'm also seeing deprecation warnings on a destination enum .sheet(item: $store.scope(state: \.destination?.settingsItem, action: \.destination.settingsItem)) { ... }
as well as one where my state is a computed var

ForEach(
  store.scope(
    state: \.filteredEntries,
    action: \.media
  )
) { ... }

[stephencelis]

We've reverted that deprecation and will reconsider it. Otherwise are things working OK?

[brzzdev]

Everything else looks good to me.
Test suite passes in both my biggest personal app, and our company app and both appear fully functional 👌🏻

[stephencelis]

Great to hear, thanks for your help!

[acosmicflamingo]

This is great! Everything works like a charm for me; test suite passes in the one app I've been working on for years. The app looks to be functional too; haven't seen any egregious behavior.

[stephencelis]

Thanks for taking the time!

[beribas]

We are currently migrating the app to ObservableState. I smoke tested the "core" branch on the new (not yet merged) state and on the previous ViewStore based, didn't face any issues. Curious about coming features as well. Thanks for improving the library!

[SoKamil]

including non-main actor stores

Does that imply that currently tests with Store has to be run on the main thread?

After migrating to Swift Testing, we are facing flaky tests with Thread 11: EXC_BREAKPOINT on TestStore.deinit. It's very hard to reproduce.

Our tests are written in the following manner:

    @Test
    func tileTapped() async {
        let store = await TestStore(initialState: .init()) {
            SomeReducer()
        }
       ....
    }

Note that after migration from XCTest we were forced to add await before the TestStore.

The only remedy I found out currently is to mark the test with @MainActor. Now, we don't have to add await.

    @Test
    @MainActor
    func tileTapped() async {
        let store = TestStore(initialState: .init()) {
            SomeReducer()
        }
       ....
    }

Is it required to add @MainActor to the tests? Are there any advantages of not doing it?

[brzzdev]

Tests that use TestStore should be marked as async since most assertion helpers on TestStore can suspend. And while tests do not require the main actor, TestStore is main actor-isolated, and so we recommend annotating your tests and suites with @MainActor.

Testing