Add structured log for unhandled promise rejections via window.onunhandledrejection

[Chucks1093]

Summary

Unhandled promise rejections (e.g. from fire-and-forget async calls outside React) are silently swallowed in production. A window.onunhandledrejection handler should capture these and emit a structured log before they disappear.

Scope

• Register a window.onunhandledrejection handler on app initialisation alongside the existing window.onerror handler
• Emit a debug-level structured log on each unhandled rejection with fields: reason, promise_origin, rejected_at
• Handler should not suppress the default browser behaviour
• Handler registered once on init, not on re-renders
• Log not emitted in the test environment

Acceptance Criteria

• Handler registered once on app init
• Structured log emitted for each unhandled rejection with all three fields
• Default browser behaviour preserved
• Handler does not duplicate logs already caught by the React error boundary
• Log not emitted in test environment

ETA: 12 hours

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Coordinate on Telegram

[malaysiaonelove]

Hi maintain,I will love to work on this issue,I have an experience and I have already reviewed the issue please assigned me to it and I will give a good result i will do my best.

[malaysiaonelove]

Hi maintain,I will love to work on this issue,I have an experience and I have already reviewed the issue please assigned me to it and I will give a good result i will do my best.

[sudo-robi]

@sudo-robi has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

Hi maintainer I'm a full stack developer and smart contract developer and auditor let me help you resolve this issue and I assure you it will be thoroughly done neatly as I have seen my way to solve the issue.

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[codewithzubair07]

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i would like to work on this issue

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[frank0277]

@frank0277 has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

Hi please please I would like to work on this

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[omarima-10]

@omarima-10 has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

Hi, my name is Omarima-10, and I am a fullstack and smart contract developer skilled in React, Next.js, JavaScript, TypeScript, Tailwind CSS, and Soroban. For this task, I will:

1. Register a single window.onunhandledrejection handler during application initialization alongside the existing window.onerror handler, ensuring it is not re-registered on component re-renders.

2. Emit a structured debug-level log for each unhandled promise rejection containing the required reason, promise_origin, and rejected_at fields, while preserving the browser's default rejection handling behaviour.

3. Ensure the handler avoids duplicate reporting for errors already captured by the React error boundary and skips logging entirely when running in the test environment.

4. Add targeted tests verifying one-time handler registration, structured log generation, test-environment exclusion, and the absence of duplicate logging or behavioural regressions.

ETA: 10 hours

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[Fabulouz34]

@Fabulouz34 has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

Hi maintainer please I will appreciate it if I'm given this issue to work on. Please assign me I'm ready to get started
Thank you

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