[Swift][Android][Bug]: Notify dismissal after checkout presentation closes

[kieran-osgood-shopify]

What changes are you making?

Make dismissal report presentation lifecycle consistently on Swift and Android, independently of checkout outcome. This is split out of #757, which only wires accelerated checkout to the existing dismissal callback; nothing here is needed for that wiring.

For Checkout Kit-managed presentations (Swift CheckoutWebViewController, Android CheckoutBottomSheet):

Path	Before	After
Close button	onDismiss / checkoutDidDismiss fires before the presentation starts closing	Fires after the presentation has closed
Terminal failure	onFail, then the presentation closes without a dismissal callback	onFail, then onDismiss after the presentation has closed
Close and swipe (or buyer dismissal then failure) racing	Can report dismissal more than once	Reports dismissal at most once per presentation
Programmatic dismissal (dismiss(animated:), CheckoutHandle.dismiss())	No callback	No callback (now documented)

Also:

• Document on CheckoutDelegate, CheckoutListener, CheckoutPresentation, ShopifyCheckout.onDismiss, AcceleratedCheckoutButtons.onDismiss, and both platform READMEs that dismissal describes presentation lifecycle, that onFail precedes onDismiss when a failure closes checkout, and that completion does not imply dismissal.
• Add coverage that accelerated checkout forwards failure followed by dismissal (Shop Pay), and that Apple Pay returns to idle after a Checkout Kit failure closes the fallback presentation.

The React Native layer in #749 depends on this contract: it treats close rather than fail as the end of a presentation.

How to test

GIVEN the Swift sample is configured with a storefront and has an item in the cart

WHEN the reviewer taps Check out and then taps the checkout close button

THEN the Xcode console should log [CheckoutKitSwiftDemo] Dismissed exactly once, after the sheet has finished animating closed

---

GIVEN the Swift sample is configured with a storefront and has an item in the cart

WHEN the reviewer taps Shop Pay and swipes the checkout sheet down

THEN the Xcode console should log [AcceleratedCheckout] Dismissed exactly once

---

GIVEN the Android sample is configured with a storefront and has an item in the cart

WHEN the reviewer opens checkout and closes it with the close button, the back gesture, or by dragging the sheet down

THEN the sample's Logs screen should record Checkout dismissed exactly once per presentation

---

Before you merge

Important

• I've added tests to support my implementation
• I have read and agree with the Contribution Guidelines
• I have read and agree with the Code of Conduct
• I've updated the relevant platform README (platforms/swift/README.md and/or platforms/android/README.md)

---

Releasing a new Swift version?

• I have bumped the version in ShopifyCheckoutKit.podspec
• I have bumped the version in platforms/swift/Sources/ShopifyCheckoutKit/ShopifyCheckoutKit.swift
• I have updated the SwiftPM/CocoaPods version snippets in platforms/swift/README.md (major version only)

Releasing a new Embedded Checkout Protocol version?

• I have bumped embeddedCheckoutProtocolAndroid in platforms/android/gradle/libs.versions.toml
• I have updated protocol/languages/kotlin/embedded-checkout-protocol/api/embedded-checkout-protocol.api if the public API changed

Releasing a new Android version?

• I have bumped checkoutKitAndroid in platforms/android/gradle/libs.versions.toml
• I have updated the Gradle/Maven version snippets in platforms/android/README.md

Tip

See the Contributing documentation for the full release process per platform.

[github-actions]

Bundle Size Budgets

Budget	Size	Limits	Result
Android AAR package (ZIP)	408.74 KiB (+201 B)	450 KiB soft / 500 KiB hard	✅ Within budget

Bundle and package size

Web bundle sizes cover shipped runtime JavaScript. Package sizes cover the full published archive, including any source maps, declarations, and documentation it contains.

Platform	Measurement	Compression	Base	Head	Delta
Android	Library package (.aar)	ZIP	408.5 KiB	408.7 KiB	+201 B

Android package files (uncompressed)

These are uncompressed file sizes; they do not sum to the compressed package size above.

File	Base	Head	Delta
classes.jar	435.2 KiB	435.4 KiB	+187 B
res/layout/checkout_view_content.xml	2.6 KiB	2.6 KiB	0 B
res/layout/checkout_sheet_content.xml	2.0 KiB	2.0 KiB	0 B
res/values/values.xml	1.3 KiB	1.3 KiB	0 B
R.txt	1.2 KiB	1.2 KiB	0 B
AndroidManifest.xml	922 B	922 B	0 B
proguard.txt	798 B	798 B	0 B
res/drawable/close.xml	431 B	431 B	0 B
res/menu/checkout_menu.xml	354 B	354 B	0 B
META-INF/com/android/build/gradle/aar-metadata.properties	157 B	157 B	0 B

How sizes are measured

Measured from the PR base SHA and PR head SHA. Web bundle rows sum shipped .js, .mjs, and .cjs files under dist/, excluding source maps and declarations. The gzip bundle size sums files compressed individually with gzip -n -9. npm package sizes are gzip-compressed .tgz archives; Android AAR sizes are ZIP archives. Package sizes are not final app binary sizes.