fix(expo): prevent duplicate purchase requests

[hyochan]

Repeated presses could start two native purchases before React disabled the Expo example's Purchase button. Keep one request pending at a time and allow another after it settles. A regression test invokes the same render's handler twice and checks that cancellation allows retry.

Checks: Expo lint and TypeScript passed; 454 library, 82 plugin, and 141 example tests passed. Pre-commit parity, layout, sponsor, and IAPKit contract audits passed.

Device evidence: iPhone 13 mini and Pixel 2 completed real Apple Sandbox and Google Play test purchases through the local IAPKit server and DEV Convex. Each created one purchase row; replay kept the same row and total. After the fix, Pixel 2 keyboard input produced one native request, zero overlapping-request errors, and successful cancellation with the button enabled again. The iPhone purchase preceded this JavaScript guard; no native code changed.

The change only affects the example's request guard. These results do not establish a live subscription-webhook integration with the separate Commerce example or an external product. Existing Commerce fixture evidence remains scoped as documented.

Summary by CodeRabbit

• Bug Fixes
  • Prevented multiple purchase requests from being initiated by rapid, repeated presses.
  • Purchase requests can be started again after the previous request completes or is canceled.
  • Preserved existing cancellation and error reporting behavior.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Advanced

Run ID: 695e697f-450f-4079-a09d-0d8d3da66e33

📥 Commits

Reviewing files that changed from the base of the PR and between baabc40 and 0ed6fbb.

📒 Files selected for processing (2)

• libraries/expo-iap/example/__tests__/purchase-flow.test.tsx
• libraries/expo-iap/example/app/purchase-flow.tsx

Included review availability: Your plan provides up to 2 included reviews per hour; 1 remains after this review.

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📝 Walkthrough

Walkthrough

The purchase flow now blocks concurrent purchase requests with a pending-state guard. The guard clears after resolution or rejection. A test covers rapid presses, cancellation, and a subsequent purchase.

Changes

Purchase request concurrency

Layer / File(s)	Summary
Pending request guard libraries/expo-iap/example/app/purchase-flow.tsx	handlePurchase ignores attempts while a request is pending. The guard resets after success or failure. Existing cancellation and formatted failure handling remain.
Concurrency regression test libraries/expo-iap/example/__tests__/purchase-flow.test.tsx	The test confirms that two rapid presses start one request, and that a later press starts another after cancellation.

Priority: ⬇️ Low

Estimated code review effort: 2 (Simple) | ~10 minutes

Change: Bug fix

Merge Risk: ⚪ Minimal · up to 0ed6f

The purchase guard blocks overlapping requests and is released after cancellation or other failures, so the change is ready to merge.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely describes the main change: preventing duplicate purchase requests in the Expo example.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 1 functions across 2 files.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch codex/guard-expo-purchase-reentry

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 76.16%. Comparing base (baabc40) to head (0ed6fbb).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #451   +/-   ##
=======================================
  Coverage   76.16%   76.16%           
=======================================
  Files         157      157           
  Lines       16676    16676           
  Branches     4807     4807           
=======================================
  Hits        12702    12702           
  Misses       3974     3974           

Flag	Coverage Δ
expo-iap	90.30% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Components	Coverage Δ
React Native IAP	93.11% <ø> (ø)
Expo IAP	90.30% <ø> (ø)
flutter_inapp_purchase	90.42% <ø> (ø)
IAPKit Server	92.05% <ø> (ø)
IAPKit Convex	61.52% <ø> (ø)

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[hyochan]

Available on main in 32c8e58. All PR checks passed. This example-only fix does not require a package release.