Merchant rules - Rule does apply even if the words doesn't contain "Coffee"

[jponikarchuk]

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Version Number: v9.3.17-7
Reproducible in staging?: Yes
Reproducible in production?: N/A - new feature, doesn't exist in prod
If this was caught during regression testing, add the test name, ID and link from BrowserStack: https://docs.google.com/document/d/1M6A82DJ5B0gJ9xjX1b9GreUYID7lDSdSb59mmH4MRXA/edit?tab=t.0
Email or phone of affected tester (no customers): N/A
Issue reported by: Applause Internal Team
Bug source: Pull Request QA execution
Device used: Galaxy A55/ Android 16
App Component: Workspace Settings

Action Performed:

Scenario 1: As Admin:
1 - Create a new rule:
2- Match type: Contains
3- Merchant: "Coffee"
4- Category: "Meals & Entertainment"
5- Save the rule

Scenario 2: As member,:
1- Create expenses with merchants:
1.1 - Create an expense of any amount, → click next → enter: Starbucks Coffee as merchant → create the expense
1.2 - Create an expense of any amount, → click next → enter: Coffee Bean & Tea as merchant → create the expense
1.3 - Create an expense of any amount, → click next → enter: Blue Bottle Coffee Shop as merchant → create the expense
1.4 - Create an expense of any amount, → click next → enter: Cafe Latte as merchant → create the expense

Expected Result:

As the rule is linked to the word coffee, expenses must be related to the category

For example:
"Starbucks Coffee" → Verify rule applies
"Coffee Bean & Tea" → Verify rule applies
"Blue Bottle Coffee Shop" → Verify rule applies

Actual Result:

The word Cafe Latte does not apply, but even so it is related to the category

For example:
"Cafe Latte" → Verify rule does NOT apply (doesn't contain "Coffee")

Workaround:

Unknown

Platforms:

• Android: App
• Android: mWeb Chrome
• iOS: App
• iOS: mWeb Safari
• iOS: mWeb Chrome
• Windows: Chrome
• MacOS: Chrome / Safari

Screenshots/Videos

1.mp4

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[melvin-bot]

Triggered auto assignment to @dylanexpensify (Bug), see https://stackoverflow.com/c/expensify/questions/14418 for more details. Please add this bug to a GH project, as outlined in the SO.

[melvin-bot]

Triggered auto assignment to @MarioExpensify (DeployBlockerCash), see https://stackoverflowteams.com/c/expensify/questions/9980/ for more details.

[github-actions]

👋 Friendly reminder that deploy blockers are time-sensitive ⏱ issues! Check out the open `StagingDeployCash` deploy checklist to see the list of PRs included in this release, then work quickly to do one of the following:

1. Identify the pull request that introduced this issue and revert it.
2. Find someone who can quickly fix the issue.
3. Fix the issue yourself.

[melvin-bot]

💬 A slack conversation has been started in #expensify-open-source

[OSBotify]

🔍 Investigation Summary

Classification: Backend bug
Causing PR: No App PR identified (High confidence)
Related Issues: None

Recommendation: NEEDS INVESTIGATION (Backend team)

This is a backend bug in the merchant rules matching logic. The App correctly sends rules with the "contains" operator to the backend API, but the backend is incorrectly matching merchants that do not contain the specified text. The fix must be implemented in the backend API, not in the App repository.

Labels: Removing DeployBlockerCash as no App PR caused this issue. Keeping DeployBlocker for backend investigation.

📋 Detailed Analysis

Evidence

• The issue reports that a merchant rule with matchType "contains" and text "Coffee" is incorrectly matching "Cafe Latte" (which does not contain "Coffee")
• This is a NEW feature that does not exist in production yet
• The merchant rules feature was introduced in the App, but the actual rule matching logic executes on the backend

Verification

• Reviewed /home/runner/_work/App/App/src/libs/actions/Policy/Rules.ts (lines 123-227)
• The App code correctly:
  • Sets the operator to CONST.SEARCH.SYNTAX_OPERATORS.CONTAINS (line 137)
  • Sends the rule to backend via SET_POLICY_CODING_RULE API command (line 226)
  • Uses the form field merchantToMatch for the pattern to match against (line 146)
• No recent App PRs in the current staging deploy modified the merchant rules logic
• Git history shows no changes to merchant rules files between production and current staging

Root Cause

The backend API is incorrectly implementing the "contains" operator for merchant rule matching. When the backend receives a rule with:

{
  filters: {
    left: "merchant",
    operator: "contains",
    right: "Coffee"
  }
}

It should only match merchants whose name contains the substring "Coffee" (case-insensitive). However, it is matching "Cafe Latte" which does not contain "Coffee".

The bug is in the backend rule evaluation engine, not in how the App constructs or sends the rules. This requires investigation and fixes in the backend codebase (likely Web-Expensify or a related backend service).