[pull] main from MetaMask:main#308
Merged
Merged
Conversation
## **Description**
This PR fixes a bug in the Polymarket prediction provider where orders
could fail due to an invalid share price calculation. The issue occurred
when slippage was applied to `minAmountReceived`, causing the calculated
share price to exceed 1 (which is mathematically impossible for
prediction market shares).
The fix introduces a cap on `minAmountWithSlippage` to ensure it never
falls below `maxAmountSpent + tickSize`, preventing the share price from
exceeding 1 while still accounting for slippage to reduce order failure
rates.
## **Changelog**
CHANGELOG entry: null
## **Related issues**
Fixes:
## **Manual testing steps**
```gherkin
Feature: Polymarket prediction order execution
Scenario: user creates a prediction market order with slippage
Given the user is on the Predict feature
And a Polymarket prediction market is available
When user creates an order with slippage applied
Then the order should execute successfully without sharePrice > 1 errors
And the minAmountReceived should be capped appropriately
```
## **Screenshots/Recordings**
<!-- If applicable, add screenshots and/or recordings to visualize the
before and after of your change. -->
### **Before**
<!-- Orders could fail with sharePrice > 1 errors -->
### **After**
<!-- Orders execute successfully with proper slippage capping -->
## **Pre-merge author checklist**
- [x] I've followed [MetaMask Contributor
Docs](https://github.com/MetaMask/contributor-docs) and [MetaMask Mobile
Coding
Standards](https://github.com/MetaMask/metamask-mobile/blob/main/.github/guidelines/CODING_GUIDELINES.md).
- [x] I've completed the PR template to the best of my ability
- [x] I've included tests if applicable
- [x] I've documented my code using [JSDoc](https://jsdoc.app/) format
if applicable
- [x] I've applied the right labels on the PR (see [labeling
guidelines](https://github.com/MetaMask/metamask-mobile/blob/main/.github/guidelines/LABELING_GUIDELINES.md)).
Not required for external contributors.
## **Pre-merge reviewer checklist**
- [ ] I've manually tested the PR (e.g. pull and build branch, run the
app, test code being changed).
- [ ] I confirm that this PR addresses all acceptance criteria described
in the ticket it closes and includes the necessary testing evidence such
as recordings and or screenshots.
<!-- CURSOR_SUMMARY -->
---
> [!NOTE]
> Adjusts slippage handling in `PolymarketProvider.placeOrder` by
flooring BUY `minAmountWithSlippage` at `maxAmountSpent + tickSize`
before rounding to avoid invalid share prices.
>
> - **Predict/Polymarket**:
> - Update `placeOrder` slippage logic:
> - Compute `_minWithSlippage = minAmountReceived * (1 - slippage)`.
> - For `BUY`, floor to `maxAmountSpent + tickSize` before rounding via
`roundOrderAmount`.
> - Use the rounded value to derive `takerAmount`.
>
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
dc8a157. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->
This file contains hidden or 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
Sign up for free
to subscribe to this conversation on GitHub.
Already have an account?
Sign in.
1 participant
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.
See Commits and Changes for more details.
Created by
pull[bot] (v2.0.0-alpha.4)
Can you help keep this open source service alive? 💖 Please sponsor : )