Firestore Web creates thousands of records in localStorage until throws QuotaExceededError

[victorwads]

Operating System

MacOs

Environment (if applicable)

Chrome 139.0.7258.128, React Web Production Build (https://finance.wads.dev/)

Firebase SDK Version

11.7.3

Firebase SDK Product(s)

Firestore

Project Tooling

Project Tooling

The app is built with the following tooling:

• React + Vite + TS
• Firebase Auth, Firestore

Detailed Problem Description

Problem description

During normal app usage, the browser started storing tens of thousands of keys in localStorage with the prefix:

firestore_mutations_firestore/[DEFAULT]/goldenunicornfc/...

I counted more than 37,711 entries of this type.
This quickly filled up the localStorage quota, making the app unusable (DevTools cannot even open the Storage tab, and any call to localStorage.setItem fails).

Additionally, a critical error is thrown in the console:

index-CoKaw0am.js:910 Uncaught Error: FIRESTORE (11.9.0) INTERNAL ASSERTION FAILED: Unexpected state (ID: b815) 
CONTEXT: {"cc":"QuotaExceededError: Failed to execute 'setItem' on 'Storage': 
Setting the value of 'firestore_clients_firestore/[DEFAULT]/goldenunicornfc/_5aPCl5rs55dDzPdHvpj9' exceeded the quota.
    at oh.setItem (...)
    at oh.uo (...)
    at oh.addLocalQueryTarget (...)
    at DO (...)
    at async cb1 (...)
    at async SO (...)"}

Expected behavior (I think)

localStorage-dump-finance-wads-dev-2025-08-17T03-24-42-197Z.json

• Firestore should primarily use IndexedDB for offline persistence.
• localStorage should only contain a small number of control keys, not tens of thousands.
• Processed mutation records should be properly cleared.

Steps and code to reproduce issue

Additional details

• Public repository: GoldenUnicornFinanceControl/Web - 74ea33f62dc9823bc70a551b0f12751398001710
• A full dump of localStorage is available (I can attach it as JSON if required).
• Firebase SDK version: initially "firebase": "^11.7.3" (in yarn.lock file)
• Browser: Chrome 139.0.7258.128

[google-oss-bot]

I couldn't figure out how to label this issue, so I've labeled it for a human to triage. Hang tight.

[MarkDuckworth]

@victorwads, is this issue something that you can reliably reproduce? If so, we could benefit from getting some debug logs from the SDK. Enabling debug logging should look something like this.

import {setLogLevel} from '@firebase/firestore';
...
setLogLevel('debug');
...

Also, is there a chance that your device was offline, or the app was not able to connect to the Firestore backend, and the app was making lots of local changes? A hunch here based on what you've shared. But it looks like the app has a bunch of pending mutations, and possibly those mutations are not getting written to the backend and therefore not getting cleared from local storage.