[Due for payment 2026-09-21] [Onyx] Investigate ConstraintError: Key already exists in the object store storage error

@mallenexpensify

Parent issue: #87844

Sentry issue: https://expensify.sentry.io/issues/APP-E0

Issue Owner

Hi I investigated and its not an Onyx bug. It comes from Convert Experiences, the third-party A/B testing service we load on every web page:

<!-- web/index.html:45 -->
<script src="//cdn-4.convertexperiments.com/v1/js/10042537-100413459.js"></script>

Their SDK keeps its own IndexedDB database (convert, stores config and signals) and inserts rows with add() instead of put():

let t = await get({key:1, store:'config'});
t ? await put({key:1, data})   // row there -> overwrite
  : await add({key:1, data});  // row missing -> insert

add() fails if the key already exists; put() overwrites. Between the read and the write nothing reserves the key, so two runs at once (two tabs, or two calls in one tab) both take the add() branch, and the second one fails with ConstraintError: Key already exists in the object store. Nothing catches the rejection, so it reaches window.onunhandledrejection — our Sentry handler — and gets filed against our project.

Why it is not Onyx:

Onyx's IndexedDB provider only uses put, delete, get, clear. There is no add() in onyx 3.0.101 or in idb-keyval.
Chromium prints "Key already exists in the object store." only for add(). Checked in a real browser: add() on an existing key gives that exact message, put() on the same key succeeds, and the error carries no stack — which matches the missing stacktrace and DOMException.code: 0 on the Sentry events.

We already filter a sibling error from the same script. setupSentry.ts ignores Non-Error promise rejection captured with value: No data found for key, with a comment naming the Convert script.

Proposed fix, same pattern as that one: add ConstraintError: Key already exists in the object store. to ignoreErrors in setupSentry.ts. thirdPartyErrorFilterIntegration cannot handle it, because the error has no stack frames to tag. Onyx never calls add(), so no real Onyx failure is hidden, and genuine storage errors still reach our logs.

The add() → put() change itself sits in vendor code, so it needs a ticket to Convert. Tracking that separately.

@mountiny

@mountiny looks like the same issue addressed in #99819, if you agree we can create a PR for this

Hi, I will be in vacation from tomorrow (08.09) until 15.09
I will find someone from my team to continue to work on this issue while I'm away

@elirangoshen

Hi! I will fill in for @elirangoshen here. @mountiny I was told you are the one to reach out to for the PR review. Let me know what you think aobut the proposed solution. Thanks!

Answered on the pr

@AndrewGable

Triggered auto assignment to @AndrewGable, see https://stackoverflow.com/c/expensify/questions/7972 for more details.

We can close this now

@mountiny

looks like payment was missing here,, can we please reopen @mountiny

cc @mallenexpensify

@mallenexpensify

Current assignee @mallenexpensify is eligible for the Awaiting Payment assigner, not assigning anyone new.

@abzokhattab

Payment Summary

Resolving PRs:

[No QA] Ignore the Convert script's duplicate-key IndexedDB rejection in Sentry #100275
Reviewer: @abzokhattab owed $250 via NewDot
Contributor: @kacper-mikolajczak does not require payment (Contractor)

BugZero Checklist (@mallenexpensify)

I have confirmed assignees, roles, and Upwork contracts look correct
I have paid out Upwork contracts / manual NewDot requests
[BugZero Assignee] I have created a GH issue for creating/updating the regression test once above steps have been agreed upon

@abzokhattab

Payment Summary

Contributor+: @abzokhattab due $250 via NewDot

@abzokhattab

Approved $250 to @abzokhattab

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[Due for payment 2026-09-21] [Onyx] Investigate `ConstraintError: Key already exists in the object store` storage error #100047

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[Due for payment 2026-09-21] [Onyx] Investigate ConstraintError: Key already exists in the object store storage error #100047

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elirangoshen commented on Sep 2, 2026

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[Due for payment 2026-09-21] [Onyx] Investigate `ConstraintError: Key already exists in the object store` storage error #100047