[KIP-247] Gasless Transaction

[ian0371]

Proposed changes

Types of changes

• Bugfix
• KIP Proposal
• KIP Improvement

Checklist

• Used the suggested template: https://github.com/kaiachain/KIPs/blob/main/kip-template.md
• I have read the CLA and signed by comment I have read the CLA Document and I hereby sign the CLA in first time contribution
• I have added necessary documentation (if appropriate)
• Any dependent changes have been merged and published in downstream modules

Related issues

Depends on #45

[ulbqb]

I have a question about invalid swap tx. When the swap transactions sent by users without CL token are removed from a block? I think we need alternative checks instead of balance check.

[ian0371]

@ulbqb It'll revert by the condition R1 (GaslessSwapRouter). Token balance check in validateTx existed but has been removed because it's difficult to make a EVM call.

[ulbqb]

In practice, there is a more complicated case. I provide some examples:

[transfer_0, approve_1, swap_2] is queue contents.
[transfer_0, approve_1, swap_2] shoud be promoted to pending.

[approve_0, swap_1, approve_2, swap_3] is a queue list.
[approve_0, swap_1, approve_2, swap_3] shoud be promoted to pending.

[approve_0, approve_1, swap_2] is a queue list.
[] shoud be promoted to pending.

[approve_0, transfer_1, swap_2] is a queue list.
[] shoud be promoted to pending.

Is this correct? And I think there is a lack of checking of nonce overall.

AP1 and SPx: approveTx.Nonce + 1 == swapTX.Nonce

[ian0371]

I think we should only allow either

• (if approve exists) when getNonce(user) == GaslessApproveTx.nonce and getNonce(user) + 1 == GaslessSwapTx.nonce
• (else) when getNonce(user) == GaslessSwapTx.nonce

Thus, these are NOT regarded as GaslessTx:

• approve_1 and swap_2 in [transfer_0, approve_1, swap_2]
• approve_2 and swap_3 in [approve_0, swap_1, approve_2, swap_3]
• approve_1 and swap_2 in [approve_0, approve_1, swap_2]

The nonce check added by previous commit was meant to imply this nonce check.

[hyeonLewis]

Suggested change

	author: Ian (@ian0371) and Ollie (@blukat29)
	author: Ian (@ian0371), Ollie (@blukat29)