Bug report: [SR-15983] Xcode 13.3 (Swift 5.6) causes error: Segmentation fault: 11 build error - Swift

Overview

New Xcode 13.3 (Swift 5.6) causes error: Segmentation fault: 11 error when building SwiftUI-Gallery iOS app project.

• https://github.com/inamiy/Actomaton-Gallery/tree/main/Examples/SwiftUI-Gallery

As of 22fb93f, there was no such build error in Xcode 13.2 (Swift 5.5), but started to occur from Xcode 13.3.

Steps to reproduce

Bug-reproducing branch: https://github.com/inamiy/Actomaton-Gallery/tree/bug/Xcode13.3-segfault

1. 22fb93f Segfault when building Xcode 13.3 (no error in Xcode 13.2)
2. 8145848 Commented-out Physics module, and Xcode 13.3 build succeeds
3. 8924c6f Re-enable part of Physics module, and Xcode 13.3 build succeeds
4. 6231b40 Re-enable more part of Physics module, and Xcode 13.3 build fails due to segfault
   • Fails for both Xcode IDE build and xcodebuild (see also make build-SwiftUI-Gallery)

So the problematic code seems to live in 6231b40 but no other clues so far. (One possible issue might be protocol extension with associated type constraint i.e. where Obj == CircleObject ?)

// NOTE: ObjectWorldExample is a protocol with `Obj` as associatedtype 
extension ObjectWorldExample where Obj == CircleObject
{
    /// Default impl.
    func draggingEmptyArea(_ objects: inout [Obj], point: CGPoint) {}

    /// Default impl.
    func dragEndEmptyArea(_ objects: inout [Obj]) {}

    /// Default impl.
    func exampleTapToMakeObject(point: CGPoint) -> Obj?
    {
        CircleObject(position: Vector2(point))
    }

    var reducer: Reducer<World.Action, World.State<Obj>, World.Environment>
    {
        World
            .reducer(
                tick: World.tickForObjects(self.step),
                tap: { objects, point in
                    if let object = exampleTapToMakeObject(point: point) {
                        objects.append(object)
                    }
                },
                draggingObj: { $0.position = Vector2($1) },
                draggingEmptyArea: self.draggingEmptyArea,
                dragEndEmptyArea: self.dragEndEmptyArea
            )
    }
}

2022/03/16 0:07 Update

43b0a84 could fortunately fix this Swift 5.6 bug by loosing associatedtype constraint from where Obj == CircleObject to where Obj: Equatable with as? Obj downcasting.

Bug fixing diff: https://github.com/inamiy/Actomaton-Gallery/compare/22fb93f...865c73d

@@ -90,7 +90,7 @@ protocol ObjectWorldExample: Example
     func exampleTapToMakeObject(point: CGPoint) -> Obj?
 }
 
-extension ObjectWorldExample where Obj == CircleObject
+extension ObjectWorldExample where Obj: Equatable // where Obj == CircleObject
 {
     /// Default impl.
     func draggingEmptyArea(_ objects: inout [Obj], point: CGPoint) {}
@@ -101,7 +101,7 @@ extension ObjectWorldExample where Obj == CircleObject
     /// Default impl.
     func exampleTapToMakeObject(point: CGPoint) -> Obj?
     {
-        CircleObject(position: Vector2(point))
+        CircleObject(position: Vector2(point)) as? Obj
     }
 
     var reducer: Reducer<World.Action, World.State<Obj>, World.Environment>

While this workaround can cope the compiler bug from developer-side, the code will now become ugly (which I don't want to merge this PR), so I believe this bug needs to be fixed by Swift compiler team.

After clone the repo, update and pre-fetch packages in terminal:

$> swift package update
$> xcodebuild -resolvePackageDependencies -scmProvider system

Then, open the Package file:

$> open Package.swift

After Xcode popup, select scheme SwiftUI-Gallery with iPhone 13 simulator and hit run button, error happens:

Is there some steps I missed or something else?

There is a strange 'Release' build bug in SwiftUI-Gallery example app (as of b8256a7 ) where following console-warning is printed on every action dispatch:

warning: the Swift runtime was unable to demangle the type of field '
'. the mangled type name is '': TypeDecoder.h:1242: Node kind 190 "" - unexpected kind. this field will show up as an empty tuple in Mirrors

While the root cause is still unknown yet, I have spent some time to collect evidences as follows.

• This bug occurs in SwiftUI-Gallery + 'Release' build only, not in other examples nor configurations
  • Possibly occurred since the initial release (I checked e64520a4d3bb07507550f8fa260bddba31b2ccca in Xcode 13.1 and 13.2, but couldn't test for old Xcode 12.5.1 because macOS 12.1 can't use it)
• Works fine if not using DebugRoot (TimeTravel feature)

As most of the example apps work correctly, this is UNLIKELY the issue of core library Actomaton.

~~Perhaps the issue might be in RootViewProtocol that uses associatedtype to abstract the type information of Root.Action so that CasePath's reflection might be failing.~~ See fix in #27 .

This PR replaces Actomaton-Basic.xcodeproj example with .swiftpm, with adding portability for iPad Swift Playgrounds without depending on this repo's root Actomaton-Gallery package. (extracting Counter example independently)

To give a try:

1. Install latest iPad Swift Playgrounds ver 4
2. Airdrop .swiftpm to iPad

See also (video): https://twitter.com/inamiy/status/1471391180760182786

Value of type 'TaskGroup' has no member 'addTask' Value of type 'TaskGroup' has no member 'waitForAll'

Getting this error while running the project on XCODE 11 Beta 3

This PR adds https://github.com/krzysztofzablocki/Inject for hot-reloading support, and organized some code.

Warning

As documented in Inject's README:

The Composable Architecture If like myself you love PointFree Composable Architecture, you’d probably want to inject reducer code, this isn’t possible in vanilla TCA because reducer code is a free function which isn’t as straightforward to replace with injection, but our fork at The Browser Company supports it.

There are currently crash issues happening while editing SwiftUI views and hot-reloading occurs in SwiftUI-Gallery, which may relate to above discussion.

This PR adds rope example where the original idea is from:

• robb on Twitter: "I believe the Home app is need of a refresh and I figured I’d throw my hat in the ring. Using SwiftUI’s TimelineView and a little bit of physics, plugging your lightbulbs into the fire socket has never been as intuitive! https://t.co/MhguMSZpTR" / Twitter
• SwiftUIで紐を表現する

https://user-images.githubusercontent.com/138476/184053291-bacf6185-4826-41a5-8079-55ca248c17b3.mp4

BREAKING CHANGE.

Overview

This PR refactors entire example code by replacing ActomatonStore module with new ActomatonUI, which is introduced in:

• https://github.com/Actomaton/Actomaton/pull/66

It's important to note that core logic (i.e. defining Action, State, Reducer) doesn't change much, as they are non-UI-layer.

Significant changes happen in SwiftUI.View-layers only where ViewStore started to live with helper WithViewStore, which allows efficient and safer SwiftUI rendering as discussed in above PR.

For example, changes in CounterView.swift will be like this diff:

(NOTE: This code is writing @ObservedObject var viewStore manually, but using WithViewStore will often reduce this boilerplate code)

Also note that RouteStore (Actomaton integration for UIKit Views) won't get affected by https://github.com/Actomaton/Actomaton/pull/66 , as its API signatures will mostly stay the same as before.

As a side note, there are some minor file / code refactoring being done aside from new module integration.

Successor of:

• https://github.com/Actomaton/Actomaton-Gallery/pull/34

This PR adds swift(<5.7) to disable -Xfrontend -requirement-machine=off for Xcode 14 (Beta 1) Swift 5.7.

This PR adds Downloader example using suspendable EffectQueue.

Also, this PR applies following Actomaton 0.5.2 bug fix:

• https://github.com/inamiy/Actomaton/pull/46

Screencast

Max 2 concurrency downloader example.

https://user-images.githubusercontent.com/138476/167300509-72c73433-4034-430b-87b3-ba20b559e0c2.mp4

This PR adds AnimationDemo to demonstrate SwiftUI Transaction (animation) handling, which also reproduces current Actomaton 0.4.0 bug that transaction doesn't work as expected.

(Before fix)

https://user-images.githubusercontent.com/138476/162989922-7735779a-2a03-48bb-b6fd-af1dc9b94218.mp4

By applying the fix in:

• https://github.com/inamiy/Actomaton/pull/39

SwiftUI animation e.g. withAnimation will now work correctly in Actomaton, except there is NavigationView issue that still doesn't handle well which is subject to investigate for future TODO.

(After fix)

https://user-images.githubusercontent.com/138476/162990924-3414e813-ba32-4a24-bd5d-1c3e93d2fd43.mp4