[E2E] Expose native preload state markers

[kyle-schellen]

What changed

• Observe PreloadState in the Swift and Android sample apps using the existing public preload callbacks.
• Expose the current state as matching, invisible test IDs such as preload-state-ready.
• Add unit tests for the cross-platform state-to-ID mappings.

Why

Maestro cannot read an in-memory Swift/Kotlin preload state. These markers let native E2E tests wait until a real checkout finishes preloading before presentation.

The markers add no visible UI and no public SDK API. The first flow only needs preload-state-ready; the other states are useful for debugging and potential future failure coverage.

PreloadState.Failed now carries a diagnostic message on both platforms. The mappings key only on the stable reason and ignore that message.

Testing

• dev swift test sample
• dev android test demo
• dev swift lint
• dev android check detekt
• Consumed by the preload E2E test in [E2E] Prepare native preload ready-flow validation #631, green on physical iOS and Android devices.

Stack

1. [E2E] Expose native preload state markers #626 — this PR: preload state markers in the samples
2. [E2E] Prove ready preload cache hits on both native samples #627 — Swift ready cache-hit diagnostic
3. [E2E] Prepare native preload ready-flow validation #631 — the E2E test, matrix wiring, and BrowserStack validation

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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.

[kyle-schellen]

• [E2E] Prepare native preload ready-flow validation #631
• [E2E] Prove ready preload cache hits on both native samples #627
• [E2E] Expose native preload state markers #626 👈 (View in Graphite)
• main

This stack of pull requests is managed by Graphite. Learn more about stacking.

[github-actions]

Package Size

Platform	Artifact	Base	Head	Delta
Android	release AAR	275.2 KiB	275.2 KiB	0 B

Android file breakdown

File	Base	Head	Delta
classes.jar	291.0 KiB	291.0 KiB	0 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
proguard.txt	798 B	798 B	0 B
AndroidManifest.xml	578 B	578 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

Measured from the PR base SHA and PR head SHA. The file breakdown shows uncompressed sizes within each package artifact, so individual files do not sum to the compressed artifact total. This comment reports package artifact sizes only; it is not a final app binary-size report.

[bitrise]

Install this build

Open Tophat, select your target device, then click Install. Links open on the Mac running Tophat.

SDK	Install
Swift	Install with Tophat
Kotlin	Install with Tophat

Checkout Kit E2E results

Status	Suite	Target	Platform	OS version tag	Device
✅	tests/shared/launch-smoke.yaml	kotlin	android	latest	Google Pixel 9 Android 17.0
✅	tests/shared/launch-smoke.yaml	swift	ios	latest	iPhone 15 iOS 27 Beta

[kieran-osgood-shopify]

Do we need a corresponding change to the react-native sample or is that already using this approach?

[kyle-schellen]

I might wait for RN because it can't use this approach yet. This PR maps the native PreloadState callbacks to identifiers, and until #654there was no equivalent on RN. #656 is already adding RN sample preload observability, so building on that makes sense imo.