[HIGH] Fully integrate Reassure into Onyx to improve performance monitoring and prevent regressions

[mountiny]

Background

Onyx is the backbone of our application, ensuring fast and reliable data access. To maintain a high-quality user experience, it is critical to monitor and measure its performance. Effective tracking allows us to detect regressions early and continuously improve efficiency.

Problem

When Onyx functions experience performance regressions, there is currently no automated way to detect them early, which makes it difficult to diagnose slowdowns and optimize performance. Without comprehensive performance testing in place, issues may go unnoticed until they affect end users, reducing app responsiveness and developer confidence in code changes.

Solution

Expand Reassure testing coverage in Onyx to ensure performance is continuously monitored and regressions are detected early.

Phase 1

1. Update Reassure version to match E/App (or latest).
2. Implement Reassure tests for all functions in Onyx.ts, OnyxUtils.ts, OnyxCache.ts, and OnyxConnectionManager.ts to maximize coverage.
3. Add guidelines and update the PR/Reviewer Checklist to ensure all new Onyx functions include Reassure test coverage.

Phase 2

1. Extend Reassure tests to remaining utilities like utils.ts and Str.ts.
2. Explore testing render counts for useOnyx.ts to detect unnecessary re-renders.
   This approach will improve Onyx’s reliability by providing continuous, automated performance validation, ensuring that any performance degradation is caught before it impacts users.

Issue Owner

Current Issue Owner: @fabioh8010

[melvin-bot]

Triggered auto assignment to @joekaufmanexpensify (Bug), see https://stackoverflow.com/c/expensify/questions/14418 for more details. Please add this bug to a GH project, as outlined in the SO.

[mountiny]

Waiting for Callstack assignee to comment

[fabioh8010]

Hi, I'm Fábio from Callstack - expert agency - and I would like to work on this issue.

[fabioh8010]

Will start working on this next week (Tuesday, will be OOO on Monday).

[fabioh8010]

Updates:

• Started to work on this today.

[fabioh8010]

Updates:

• I'm splitting the work with other tasks, but slowly making progress here. Will publish a WIP Draft PR soon.

[fabioh8010]

Updates:

• Implemented most of the tests for Onyx.ts.
• Created WIP Draft PR here.

[melvin-bot]

@fabioh8010 @mountiny @joekaufmanexpensify this issue was created 2 weeks ago. Are we close to a solution? Let's make sure we're treating this as a top priority. Don't hesitate to create a thread in #expensify-open-source to align faster in real time. Thanks!

[joekaufmanexpensify]

@fabioh8010 will a PR be up this week?

[fabioh8010]

@joekaufmanexpensify I'm more confident to have the PR ready next week.

[joekaufmanexpensify]

Got it, sounds good. Thanks for the update!

[fabioh8010]

Updates:

• Implementing tests for OnyxUtils.ts.