feat: custom slippage improvements for UI and cowswap swapper

[woodenfurniture]

Description

Some types of swappers (thorchain streaming swaps) dont support the ability to specify the slippage when getting a quote, and we need a way to propagate this to users. Other swappers (0x) only provide slippage protection for certain pairs.

This PR implements a UI change that shows users what quotes are affected.

• Includes custom slippage capability for cowsap
• 0x only provides slippage protection for specific pairs, so this PR addresses that
• Fixes trade execution UI showing the default slippage instead of custom slippage

Pull Request Type

• 🐛 Bug fix (Non-breaking Change: Fixes an issue)
• 🛠️ Chore (Non-breaking Change: Doc updates, pkg upgrades, typos, etc..)
• 💅 New Feature (Breaking/Non-breaking Change)

Issue (if applicable)

closes #5779

Risk

• Risk of broken trades
• Risk of incorrect custom slippage for cow swap

Testing

• Check trades are working as expected
• Check cowswap custom slippage is correct

Engineering

Carefully check the implementation of custom slippage for cowswap.

Operations

Screenshots (if applicable)

Cowswap default slippage value - see matching payload

Cowswap custom slippage value - see matching payload

Completed cow trade with custom slippage (note bottom right of UI

Video showing slippage UI behaviour

slippage.mov

[woodenfurniture]

Current dependencies on/for this PR:

• develop
  • PR feat: custom slippage improvements for UI and cowswap swapper #5908 👈

This stack of pull requests is managed by Graphite.

[gomesalexandre]

Non-blocking, but can we use a consistent vernacular for both of these? i.e slippageDecimal or slipperPercentage (perhaps percentageDecimal).
Reading this is a bit confusing

[gomesalexandre]

Also, can we use a different terminology than error here? While we do display it as an error for users, not being able to set custom slippage is not an actual runtime error, it's part of the flow for swappers that don't support it, so this adds to the confusion

[woodenfurniture]

yeah agreed, I've pushed a commit to align things a bit better 8996988

[woodenfurniture]

also a88fa6b

[gomesalexandre]

Tested locally. Conceptual stamp except for one question.

1inch

• Default slippage

• Custom slippage is honored at final quote time

CoW

• Default slippage

• Custom slippage is honored

According to this implementation:

https://github.com/cowprotocol/cowswap/blob/071ce71b22d25a7767547f39254a5845132622a4/libs/common-utils/src/misc.ts#L176-L182

100 indeed is correct as 1% slippage ✅

THOR non-streaming swaps

• Default slippage

• Custom slippage

@woodenfurniture the default 1% doesn't seem to be reflected at quote time here, though I believe this is on purpose because of our implementation, as we use limit over slippage? Memo for reference: =:THOR.RUNE:thor125dwsa39yeylqc7pn59l079dur502nsleyrgup:194410385:ss:0

https://viewblock.io/thorchain/tx/c8ceabdf8aad8f680a79c27ee1625942d103c06a17144dc7d09776c3d0ad68bb

Streaming swaps

• Default slippage bps

• Custom slippage

Custom slippage is unable to get set for streaming swaps, and auto bps are used as they should ✅

[woodenfurniture]

@woodenfurniture the default 1% doesn't seem to be reflected at quote time here, though I believe this is on purpose because of our implementation, as we use limit over slippage? Memo for reference: =:THOR.RUNE:thor125dwsa39yeylqc7pn59l079dur502nsleyrgup:194410385:ss:0

correct, we're manually implementing slippage through the limit mechanism here:
src/lib/swapper/swappers/ThorchainSwapper/utils/addSlippageToMemo.ts

[gomesalexandre]

Akschual stamp after q. has been answered.