fix(ios): prevent Apple Pay double Promise resolve crash

[jparlej]

Summary

• Fixes a fatal iOS crash during Apple Pay: the native Nitro promise was settled twice when the payment sheet dismissed (Failed to resolve promise ... it has already been resolved or rejected!).
• Makes handlePaymentResult one-shot (clears the completion callback and delegate after the first settle), matching the Android handler.
• Settles both success and cancel only from paymentAuthorizationViewControllerDidFinish, so authorize + dismiss cannot double-resolve the same promise.

Problem

On iOS, authorizing Apple Pay resolved the Nitro promise from didAuthorizePayment, while dismissing the sheet could resolve it again from didFinish (or a second callback hit the same unfinished completion). Nitro treats a second resolve as a fatal error and kills the app. Android already nulls out the promise after the first settle; iOS did not.

Test plan

• iOS: complete Apple Pay → success result, no crash
• iOS: cancel Apple Pay sheet → failure result, no crash
• iOS: background during sheet, then return
• iOS: cancel and immediately start another payment
• Android Google Pay unchanged
• After merge: cut a release so consumers can pick up the fix

[coderabbitai]

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• package/ios/HybridPaymentHandler.swift

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• package/ios/HybridPaymentHandler.swift

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📝 Summary

Summary by CodeRabbit

• Bug Fixes
  • Improved iOS payment completion handling so successful authorizations are reported after the authorization flow finishes.
  • Prevented payment results from being processed more than once.
  • Improved consistency when payments are canceled, dismissed, or encounter creation or presentation errors.
  • Added a brief completion delay to support reliable authorization results.
  • Prevented overlapping payment attempts from starting while another payment is in progress.

Walkthrough

The iOS payment handler defers successful results until authorization finishes. It distinguishes cancellation from early dismissal. It settles each payment once, clears shared state, rejects overlapping payments, and routes creation and presentation failures through the same handler.

Changes

Payment settlement lifecycle

Layer / File(s)	Summary
Deferred authorization result package/ios/HybridPaymentHandler.swift	The handler stores successful payment results and returns them from didFinish after authorization dismissal. Unsuccessful dismissal retains the cancellation and early-dismissal distinction.
One-shot payment settlement package/ios/HybridPaymentHandler.swift	The handler rejects overlapping payments before replacing active state, clears shared state after settlement, and routes payment creation and presentation failures through the shared result handler.

Priority: ⬆️ High

Estimated code review effort: 3 (Moderate) | ~20 minutes

Change: Bug fix

Merge Risk: ⚪ Minimal · up to 697e5

The payment lifecycle clears shared state before settling and rejects overlapping requests without replacing the active callback. No actionable merge risk remains.

🚥 Pre-merge checks | ✅ 5 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 50.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 4 functions across 1 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly describes the iOS Apple Pay double-resolution crash and includes the required fix type. It is 56 characters, which exceeds the preferred 50-character limit but remains concise and de…
Description check	✅ Passed	The description directly explains the Apple Pay Promise crash, the one-shot settlement fix, overlapping payment protection, and the test plan.
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.
Security Check	✅ Passed	No medium-, high-, or critical-severity vulnerability is introduced by this PR. The authoritative diff changes only package/ios/HybridPaymentHandler.swift. The added code stores the authorized PassK…

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Actionable comments posted: 1

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Inline comments:
In `@package/ios/HybridPaymentHandler.swift`:
- Around line 285-289: Update startPayment/performPayment to prevent a new
payment from replacing shared state while paymentCompletion is non-nil: reject
the overlapping request before assigning paymentCompletion, delegate, or
currentPaymentRequest, while preserving normal cleanup and completion behavior
in handlePaymentResult.

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Configuration used: Organization UI

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Reviewing files that changed from the base of the PR and between 2078fdd and 93d0b71.

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• package/ios/HybridPaymentHandler.swift

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