Safer swap fee bounds #1054
Open
Safer swap fee bounds #1054
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
…ce that's not really the maximum fee)
# Conflicts: # pkg/pool-stable/test/gas/.hardhat-snapshots/[StablePool - Standard] add liquidity unbalanced - warm slots # pkg/pool-stable/test/gas/.hardhat-snapshots/[StablePool - With rate] remove liquidity single token exact out - warm slots
# Conflicts: # pkg/vault/test/.contract-sizes/VaultAdmin
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Description
We check that the swap fee can never be > 100% (to keep the math well-behaved), but if it is exactly 100%, ExactOut swaps will revert with an arithmetic error, which is not ideal.
It is also confusing that we have something called MAX_FEE_PERCENTAGE that is set to 1e18 - when the actual maximum fee is less than that. Also, it is used interchangeably with 1e18/FixedPoint.ONE, which makes an invalid assumption.
This sets the values that should be 1e18 to FixedPoint.ONE, and sets MAX_FEE_PERCENTAGE to a value less than 1e18. Since we also have precision constraints, it is reasonable to set it to the maximum value under 100% that meets the precision.
The same fix applies to the pool creator fee (i.e., in case all other fees are 0, to keep the LP fees > 0).
Type of change
Checklist:
main, or there's a description of how to mergeIssue Resolution
Resolves #1053
Resolves #887