ERC20 Allowance checks broken

[jeje]

Hi,

I don't understand why the SDK expects almost an unlimited ERC20 allowance. For a buy offer, if the allowance is gte than the offered purchase price (+ optional fees), it should work.

I skipped the SDK functions for allowance checks but now I'm stuck with the orderbook which does the same checks.

How to reproduce:

• approve 10 WMATIC to be spent by 0x
• make a buy offer on a NFT for 5 WMATIC => allowance is checked against a max instead of 5 WMATIC https://github.com/trader-xyz/nft-swap-sdk/blob/6533549512a6cdbbf7cbb06bb389bfb2327b0044/src/sdk/v4/pure.ts#L138

[johnrjj]

Thanks, for reporting. We will add that in a future release -- definitely very valid feedback. I'll update the orderbook to only check for minimum required allowances.

[jinsley8]

@johnrjj - Do you know if there is a workaround for this? @jeje Did you figure it out?

Metamask used to default to max spend but with a newer version update it now lets you specify spend by default.

If trading any ERC20 tokens then you have to click Use default to select max limit of 332306998946228968.225951765070086144

Otherwise if you put any custom value (larger than the ERC20 amount) or even if you click on Max which is the max amount in your wallet, the transaction will end up failing.

I've even tried allowance amounts of 1 WETH more than my wallet and it loadApprovalStatus() still detects it as unapproved.

[jeje]

@jeje Did you figure it out?

We are running our own orderbook instead as we needed other features like offchain auctions.

[johnrjj]

This is fixed with version 0.3.2 release!

[jinsley8]

Sweet, thank you!

[johnrjj]

Linking release notes: https://github.com/trader-xyz/nft-swap-sdk/releases/tag/v0.32.0

[johnrjj]

Closed as fixed. Please open another issue if there's more feature requests!