fix/account-tracker-prevent-empty-state-update

[salimtb]

Explanation

This change prevents AccountTrackerController from overwriting cached balances with empty or unchanged state during refresh operations.

Currently, if all balance requests for a chain fail or return undefined (e.g., due to a temporary network issue), the controller updates the state with an empty object, erasing previous data. Additionally, even when the new balance data is identical to the current state, an update is still triggered, resulting in unnecessary stateChange emissions and potential UI re-renders.

This update introduces guards within the refresh method to:

• Skip updates if the computed accountsForChain object is empty.
• Skip updates if the resulting balances are identical to the current state.
• Prevent stale or partial data from overriding valid cached values.
• Reduce unnecessary re-renders and state emissions.

These changes help improve performance and stability, particularly under poor network conditions or when balance polling is frequent.

References

• Fixes #15472

Changelog

@metamask/assets-controllers

UPDATE: Prevent AccountTrackerController from updating state with empty or unchanged data during balance refresh. Adds checks to avoid overwriting valid cached balances and reduce unnecessary stateChange emissions.

Checklist

• I've updated the test suite for new or updated code as appropriate
• I've updated documentation (JSDoc, Markdown, etc.) for new or updated code as appropriate
• I've communicated my changes to consumers by updating changelogs for packages I've changed, highlighting breaking changes as necessary
• I've prepared draft pull requests for clients and consumer packages to resolve any breaking changes