Top Up flow for Bridge Balance starts without checking source chain balance

[karinayavorska]

Describe the bug
The bridge lacks validation for the token amount when the "Top Up" flow is triggered. A user can enter an amount greater than their actual balance and still proceed to "Top Up" ETH. After the ETH deposit is confirmed, the UI locks the input field, preventing the user from correcting the amount. Attempting to proceed with the transfer results in a "Missing revert data" (CALL_EXCEPTION) error.

Preconditions
Bridge Balance is 0 or insufficient.
Wallet has enough ETH on Mainnet to perform a Top Up.
Wallet has a specific amount of SKL (e.g., 4324 SKL).

To Reproduce
Steps to reproduce the behavior:

1. Go to Bridge
2. Select any SKALE Chain as "From" and Ethereum Mainnet as "To".
3. Enter an amount greater than your current balance.
4. Observe that no "Insufficient balance" warning appears.
5. Click the "Top Up ETH" button.
6. Confirm the transaction in MetaMask.
7. Once the Top Up is successful, observe that the amount input field is now disabled.
8. Click "Transfer" and confirm in MetaMask.
9. See error: "Missing revert data".

Expected behavior
The system should validate the token balance before allowing a Top Up. If the entered amount exceeds the balance, a warning like "Insufficient balance" should appear, and the "Top Up" button should be disabled or the UI should not lock the input field after a Top Up, allowing the user to correct the amount.

Version
5.0.0-beta.6

Screenshots

Desktop:

• OS: Ubuntu 24.04.2 LTS
• Browser Chrome
• Version 147.0.7727.101