Dismiss and Alert ends with strange behaviour

[mpiotrowskibsg]

Description

It seems that there is issue with presenting and dismissing in new navigation API. Checking Integration app and new Presentation API I can see issue where I use Dismiss and Alert. It ends with just dismissing and console error. It also makes next presentation broken because it is presented and automatically dismissed.

Checklist

• I have determined whether this bug is also reproducible in a vanilla SwiftUI project.
• If possible, I've reproduced the issue using the main branch of this package.
• This issue hasn't been addressed in an existing GitHub issue or discussion.

Expected behavior

1. Presented screen is dismissed
2. Alert is shown

Actual behavior

1. Presented screen is dismissed
2. Error is printed on cosole
3. Next presentation is broken

Steps to reproduce

1. Open Integration app
2. Select Presentations APIs
3. Press Open Sheet
4. Press Dismiss and Alert
5. Press again Open Sheet to see next broken presentation

The Composable Architecture version information

prerelease/1.0

Destination operating system

iOS 16.1

Xcode version information

14.1

Swift Compiler version information

swift-driver version: 1.62.15 Apple Swift version 5.7.1 (swiftlang-5.7.1.135.3 clang-1400.0.29.51)
Target: arm64-apple-macosx12.0

[stephencelis]

@mpiotrowskibsg Our integration suite doesn't have a ton of documentation at the moment, but it shouldn't be viewed as "case studies" of working examples. It doesn't just exercise happy paths, but also exercises "unhappy" paths that sometime demonstrate some unfortunate vanilla SwiftUI behavior. In this case, SwiftUI itself just doesn't support programmatically swapping a sheet with an alert. The workaround most folks seem to apply is to space out dismissal and presentation using delays.

I'm going to convert this issue to a discussion since it's not a bug with the library, but rather a current behavior of vanilla SwiftUI.

[mbrandonw]

And we even have a test that demonstrates the bug, and so hopefully someday this test will start passing:

swift-composable-architecture/Examples/Integration/IntegrationUITests/PresentationTests.swift

Lines 315 to 324 in bbdfd26

	func testDismissAndAlert() async throws {
	self.app.buttons["Open sheet"].tap()
	XCTAssertEqual(self.app.staticTexts["Count: 0"].exists, true)
	self.app.buttons["Dismiss and alert"].tap()
	XCTTODO("""
	This test should pass but does not due to a SwiftUI bug. You can now simultaneously close
	a sheet and open an alert.
	""")
	XCTAssertEqual(self.app.staticTexts["Alert open"].exists, true)
	}