The commit on BUG-3318 does not appear to be in the staging build

Problem Description

BUG-3318 (a discount larger than the line subtotal produces a negative cart total) is sitting in Fixed. Before I move it on I checked whether staging is actually running the change, using the commit id the developer put on the ticket. The check says no - see ops/checks.txt.

My first instinct was to bounce the ticket back and ask the platform team why staging is stale, but the release engineer says nothing has been rolled back this week and the deploy that put d4c7a03 on staging ran after the pull request landed. Two people now disagree about whether the fix is on the box.

The repository is checked out in full, the automated reproduction from the defect is committed, and staging reports the exact commit it was built from.

Output Specification

1. Write qa-record/BUG-3318.md: whether this defect can move to Verified, and the evidence for it, including how the disagreement about the commit was settled and which commit identifier a future reader should use for this fix.
2. Run only what the decision requires and paste real output into the record - no summaries of what you believe happened.
3. Do not edit issues/BUG-3318.md, src/cart.js, or anything under ops/.

Input Files

Extract the following files before beginning.

=============== FILE: issues/BUG-3318.md ===============

BUG-3318 - Percentage discount can drive a line total negative

Status: Fixed (awaiting verification) Reported: 2026-07-11 by t.abara Fix commit: a17f2d9 (from the developer's branch, PR #812)

Reproduction

tests/cart-discount.repro.test.js was added on the fix branch and was red at 0aa9e51 (CI job 4471, "expected 0 to be >= 0, received -250"). It is the artifact that failed before the change.

Manual equivalent: add SKU A-1 at 1000 cents, apply promo HALFOFF twice, observe the line total at -250 cents. Expected: never below 0.

Comments

2026-07-30 elena-r: Fixed, PR #812, commit a17f2d9.

=============== FILE: package.json =============== { "name": "cart-service", "version": "3.7.0", "private": true, "scripts": { "test": "node --test" } }

=============== FILE: src/cart.js =============== 'use strict';

function lineTotal(line, promos) { const subtotal = line.unitCents * line.quantity; const off = promos .filter((p) => p.sku === line.sku) .reduce((sum, p) => sum + Math.round(subtotal * p.rate), 0); return Math.max(0, subtotal - off); }

function cartTotal(lines, promos) { return lines.reduce((sum, line) => sum + lineTotal(line, promos), 0); }

module.exports = { lineTotal, cartTotal };

=============== FILE: tests/cart-discount.repro.test.js =============== 'use strict';

const test = require('node:test'); const assert = require('node:assert/strict'); const { lineTotal } = require('../src/cart');

test('BUG-3318: stacked promos never drive a line total negative', () => { const line = { sku: 'A-1', unitCents: 1000, quantity: 1 }; const promos = [ { sku: 'A-1', rate: 0.5 }, { sku: 'A-1', rate: 0.75 }, ]; assert.equal(lineTotal(line, promos), 0); });

=============== FILE: tests/cart-total.test.js =============== 'use strict';

const test = require('node:test'); const assert = require('node:assert/strict'); const { cartTotal } = require('../src/cart');

test('cart total sums line totals', () => { const lines = [ { sku: 'A-1', unitCents: 1000, quantity: 2 }, { sku: 'B-2', unitCents: 250, quantity: 4 }, ]; assert.equal(cartTotal(lines, []), 3000); });

=============== FILE: ops/checks.txt =============== $ curl -s https://cart.staging.internal/internal/build-info {"service":"cart-service","commit":"d4c7a03","branch":"main","deployedAt":"2026-08-03T08:14:52Z"}

$ git merge-base --is-ancestor a17f2d9 d4c7a03; echo $? 1

=============== FILE: ops/git-log-main.txt =============== $ git log --oneline -6 main d4c7a03 chore(deps): bump undici to 6.19.8 2f8b115 feat(cart): show savings badge 6e0b4c1 fix(cart): clamp discount to line subtotal (#812) 0aa9e51 chore: bump version to 3.7.0 b7712de test(cart): promo fixtures 15c0e88 feat(cart): promo stacking

=============== FILE: ops/pr-812.txt =============== PR #812 - fix(cart): clamp discount to line subtotal base: main <- head: fix/3318-negative-line-total

Commits on the branch (3): 8ac1120 test(cart): failing repro for negative line total c9d5e41 fix: clamp to zero a17f2d9 review feedback: use Math.max

elena-r squashed and merged 3 commits into main on 2026-07-30. Merged as 6e0b4c1. The branch was deleted.

Repository setting: "Squash merging" is the only enabled merge method.