feat(predict): add FAK order type support by matallui · Pull Request #26718 · MetaMask/metamask-mobile

matallui · 2026-02-27T22:58:07Z

Description

Adds Fill-and-Kill (FAK) order type support, feature-flagged OFF by default via the predictFakOrders version-gated remote flag.

How it works:
When both conditions are met:

Permit2 fee authorization is active (Permit2 allowance exists AND being used)
fakOrdersEnabled flag is true (via predictFakOrders remote flag)

→ The order is submitted with OrderType.FAK instead of OrderType.FOK.

In all other cases (no Permit2, fallback to Safe tx, or fakOrdersEnabled false), orders continue to use OrderType.FOK.

Changes (~20 lines of logic):

Add fakOrdersEnabled: boolean to PredictFeatureFlags
Resolve predictFakOrders version-gated remote flag in resolveFeatureFlags()
In placeOrder(): when Permit2 path is taken AND fakOrdersEnabled → OrderType.FAK
4 new test cases covering FAK/FOK selection logic

Double-gated safety: FAK requires both Permit2 AND the FAK flag. The predictFakOrders flag is version-gated, so old app versions won't get FAK even if the remote flag is enabled.

Depends on: #26711 (Permit2 fee authorization)

Changelog

CHANGELOG entry: null

Related issues

Fixes: https://consensyssoftware.atlassian.net/browse/PRED-715

Manual testing steps

Feature: FAK order type support (feature-flagged OFF)

  Scenario: user places orders with FAK disabled (default)
    Given user has Predict feature enabled
    And fakOrdersEnabled remote flag is false (default)

    When user places a buy order (even with Permit2 active)
    Then order type is FOK

  Scenario: user places orders with FAK enabled and Permit2 active
    Given user has Predict feature enabled
    And fakOrdersEnabled remote flag is true
    And permit2Enabled is true with executors configured
    And user's Safe has Permit2 USDC allowance

    When user places a buy order
    Then order type is FAK
    And Permit2 fee authorization is used

  Scenario: user places orders with FAK enabled but no Permit2
    Given user has Predict feature enabled
    And fakOrdersEnabled remote flag is true
    And Permit2 conditions are NOT met (no allowance or flag off)

    When user places a buy order
    Then order type is FOK (fallback)
    And Safe transaction fee authorization is used

Screenshots/Recordings

N/A — backend logic, no UI changes.

Before

N/A

After

N/A

Pre-merge author checklist

I've followed MetaMask Contributor Docs and MetaMask Mobile Coding Standards.
I've completed the PR template to the best of my ability
I've included tests if applicable
I've documented my code using JSDoc format if applicable
I've applied the right labels on the PR (see labeling guidelines). 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.

Note

Medium Risk
Changes Polymarket order submission to conditionally use a new FAK order type, which can affect trade execution semantics and request signing when enabled. Risk is mitigated by a version-gated remote flag and only applying the behavior on the Permit2 fee-authorization path.

Overview
Adds a new fakOrdersEnabled feature flag (resolved from the version-gated remote flag predictFakOrders) to control whether Predict orders may be submitted as Fill-and-Kill.

Updates Polymarket placeOrder to choose OrderType.FAK only when Permit2 fee authorization is actually used and fakOrdersEnabled is true (otherwise it remains FOK), and restructures header signing so the HMAC covers the selected orderType.

Expands Polymarket provider tests to cover FAK vs FOK selection across Permit2, Safe fallback, and flag combinations.

^{Written by Cursor Bugbot for commit 054dccc. This will update automatically on new commits. Configure here.}

github-actions · 2026-02-27T22:58:15Z

CLA Signature Action: All authors have signed the CLA. You may need to manually re-run the blocking PR check if it doesn't pass in a few minutes.

Add fakOrdersEnabled to PredictFeatureFlags interface and resolve predictFakOrders version-gated remote flag in resolveFeatureFlags(). Defaults to false when the remote flag is absent or invalid.

…re active When a Permit2 fee authorization is used AND fakOrdersEnabled is true, submit the order with OrderType.FAK instead of FOK. Falls back to FOK in all other cases (no Permit2, no allowance, or fakOrdersEnabled false).

cursor

Cursor Bugbot has reviewed your changes and found 1 potential issue.

^{Bugbot Autofix is OFF. To automatically fix reported issues with cloud agents, have a team admin enable autofix in the Cursor dashboard.}

Hoist fee/permit2/FAK determination before clobOrder construction so the HMAC signature covers the correct orderType (FAK vs FOK) instead of always signing FOK and overriding afterward.

github-actions · 2026-03-02T20:05:07Z

🔍 Smart E2E Test Selection

Selected E2E tags: SmokePredictions, SmokeWalletPlatform, SmokeConfirmations
Selected Performance tags: @PerformancePredict
Risk Level: medium
AI Confidence: 85%

click to see 🤖 AI reasoning details

E2E Test Selection:
The changes are focused on the Predictions/Polymarket feature, specifically adding support for FAK (Fill-And-Kill) order types when using Permit2 fee authorization. The changes include:

PredictController.ts: Added extraction of a new fakOrdersEnabled feature flag from remote feature flags
PolymarketProvider.ts: Modified order placement logic to use FAK order type instead of FOK when Permit2 is used AND the feature flag is enabled. The code was restructured to determine the order type before building the clobOrder for correct HMAC signature calculation.
flags.ts: Added the new fakOrdersEnabled boolean to the PredictFeatureFlags interface
PolymarketProvider.test.ts: Added comprehensive unit tests covering all scenarios (FAK with Permit2+flag, FOK without flag, FOK with Safe tx fallback)

Selected tags based on tag descriptions:

SmokePredictions: Primary tag - tests Polymarket prediction market integration including opening/closing positions
SmokeWalletPlatform: Required per SmokePredictions description - Predictions is a section inside the Trending tab
SmokeConfirmations: Required per SmokePredictions description - opening/closing positions are on-chain transactions

The risk is medium because:

Changes affect trading/order placement logic which is financially sensitive
However, the change is feature-flag gated (fakOrdersEnabled)
Well-covered by unit tests
Isolated to Predict functionality with no broader impact

Performance Test Selection:
The changes modify order placement logic in PolymarketProvider which is part of the prediction market flow. While the changes are primarily logic-based (order type selection), they do restructure the order building process. The @PerformancePredict tag covers prediction market flows including deposit flows and order execution, which could be affected by the restructured order building logic. Running this performance test will help ensure the changes don't introduce any performance regressions in the prediction market flow.

View GitHub Actions results

github-actions · 2026-03-02T20:36:40Z

⚠️ E2E Fixture Validation — Structural changes detected

Category	Count
New keys	60
Missing keys	0
Type mismatches	0
Value mismatches	6 (informational)

The committed fixture schema is out of date. To update, comment:

@metamaskbot update-mobile-fixture

View full details | Download diff report

caieu

LGTM

matallui added no-changelog no-changelog Indicates no external facing user changes, therefore no changelog documentation needed team-predict Predict team labels Feb 27, 2026

github-actions Bot added the size-M label Feb 27, 2026

Base automatically changed from predict/permit2-pr2 to main March 2, 2026 18:32

matallui added 2 commits March 2, 2026 11:41

feat(predict): add fakOrdersEnabled feature flag

a4230b9

Add fakOrdersEnabled to PredictFeatureFlags interface and resolve predictFakOrders version-gated remote flag in resolveFeatureFlags(). Defaults to false when the remote flag is absent or invalid.

matallui force-pushed the predict/permit2-pr3 branch from ba7ae0d to 7d29258 Compare March 2, 2026 18:42

matallui marked this pull request as ready for review March 2, 2026 18:42

matallui requested a review from a team as a code owner March 2, 2026 18:42

cursor Bot reviewed Mar 2, 2026

View reviewed changes

Comment thread app/components/UI/Predict/providers/polymarket/PolymarketProvider.ts Outdated

fix(predict): determine order type before HMAC computation

054dccc

Hoist fee/permit2/FAK determination before clobOrder construction so the HMAC signature covers the correct orderType (FAK vs FOK) instead of always signing FOK and overriding afterward.

matallui enabled auto-merge March 2, 2026 21:22

caieu approved these changes Mar 2, 2026

View reviewed changes

matallui added this pull request to the merge queue Mar 2, 2026

Merged via the queue into main with commit 19b3758 Mar 2, 2026
98 checks passed

matallui deleted the predict/permit2-pr3 branch March 2, 2026 23:25

github-actions Bot locked and limited conversation to collaborators Mar 2, 2026

metamaskbot added the release-7.69.0 Issue or pull request that will be included in release 7.69.0 label Mar 2, 2026

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feat(predict): add FAK order type support#26718

feat(predict): add FAK order type support#26718
matallui merged 3 commits into
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predict/permit2-pr3

matallui commented Feb 27, 2026 •

edited by cursor Bot

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matallui commented Feb 27, 2026 • edited by cursor Bot Loading Uh oh! There was an error while loading. Please reload this page.

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Description

Changes (~20 lines of logic):

Changelog

Related issues

Manual testing steps

Screenshots/Recordings

Before

After

Pre-merge author checklist

Pre-merge reviewer checklist

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github-actions Bot commented Feb 27, 2026

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github-actions Bot commented Mar 2, 2026

🔍 Smart E2E Test Selection

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matallui commented Feb 27, 2026 •

edited by cursor Bot

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