The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated (UTC)
stack-auth-hosted-components	Ready	Preview, Comment	Mar 26, 2026 5:21pm
stack-backend	Ready	Preview, Comment	Mar 26, 2026 5:21pm
stack-dashboard	Ready	Preview, Comment	Mar 26, 2026 5:21pm
stack-demo	Ready	Preview, Comment	Mar 26, 2026 5:21pm
stack-docs	Ready	Preview, Comment	Mar 26, 2026 5:21pm

No actionable comments were generated in the recent review. 🎉

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

_{Comment @coderabbitai help to get the list of available commands and usage tips.}

Greptile Summary

This PR adds fallback handling for SMTP 4yz response codes in emails-low-level.tsx so that any unrecognised temporary-class server error is marked canRetry: true rather than falling through to the non-retryable "unknown error" path. The change is well-targeted and correctly placed — it sits after all explicit per-code handlers and before the string-based temporaryErrorIndicators block, so it only fires when no more-specific rule has already matched.

Key points:

• A small helper is4yzErrorCode(code) is introduced with correct range and type-guard logic.
• The new errorType: 'TRANSIENT_NEGATIVE_COMPLETION_REPLY' is used purely for logging/display; downstream queue logic branches only on canRetry, so no existing behaviour is broken.
• The error message "The email server is too busy" is a slight over-fit — not all 4xx codes mean the server is busy — consider a more neutral phrasing.
• The fallback silently absorbs previously-uncaptured 4xx codes, removing the captureError signal that would have alerted the team to novel codes worth explicitly handling.

Confidence Score: 5/5

Safe to merge — the change is a targeted, correctly-placed fallback with no risk of breaking existing retry or failure logic.

The logic is sound: is4yzErrorCode is correctly implemented, the fallback is placed after all explicit handlers, and canRetry is the only field downstream code branches on. Both open comments are P2 style/observability suggestions that don't affect correctness or production reliability.

No files require special attention.

Important Files Changed

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A[sendMail throws Error] --> B{error instanceof Error?}
    B -- No --> G[temporaryErrorIndicators check]
    B -- Yes --> C{code / errno checks\nEDNS / EAUTH / ETIMEDOUT\nEENVELOPE / socket close}
    C -- Matched --> D[Return specific Result.error\ncanRetry per code]
    C -- No match --> E{is4yzErrorCode\nresponseCode?}
    E -- Yes --> F[Return TRANSIENT_NEGATIVE_COMPLETION_REPLY\ncanRetry: true NEW]
    E -- No --> G
    G -- indicator match --> H[Return UNKNOWN\ncanRetry: true]
    G -- no match --> I[captureError\nReturn UNKNOWN\ncanRetry: false]

_{Reviews (1): Last reviewed commit: "refactor: retry all 4yz smtp errors" | Re-trigger Greptile}