From 47e9fee7ec506b231c5241c9abe6e1f2bc24fa8b Mon Sep 17 00:00:00 2001
From: Justin Gasper <jmgasper@gmail.com>
Date: Fri, 22 May 2026 11:18:12 +1000
Subject: [PATCH] PM-5043: Restore locked challenge fee fallback

What was broken
Locked challenge rows in the billing account details modal could show a blank Challenge Fee value when challenge markup hydration did not resolve, even though the row still had the billing-account markup needed to calculate the fee.

Root cause
The prior PM-5043 modal fix moved challenge rows to challenge-specific markup, but canonical challenge rows returned undefined while hydration was missing or failed. Locked rows store member-payment subtotals directly, so the fee calculation had no fallback markup and rendered "-".

What was changed
The modal now falls back to billing-account markup when challenge-specific markup is unavailable, while preserving hydrated challenge markup values including zero. This keeps locked challenge fees populated without changing consumed-row subtotal handling.

Any added/updated tests
Added BillingAccountLineItemsModal regression coverage for a locked challenge row whose challenge markup cannot be loaded, asserting the member payments remain unchanged and the Challenge Fee is still calculated.
---
 .../BillingAccountLineItemsModal.spec.tsx     | 27 +++++++++++++++++++
 .../BillingAccountLineItemsModal.tsx          |  8 +++---
 2 files changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/apps/work/src/lib/components/BillingAccountLineItemsModal/BillingAccountLineItemsModal.spec.tsx b/src/apps/work/src/lib/components/BillingAccountLineItemsModal/BillingAccountLineItemsModal.spec.tsx
index faa3114c1..8cbd9e45e 100644
--- a/src/apps/work/src/lib/components/BillingAccountLineItemsModal/BillingAccountLineItemsModal.spec.tsx
+++ b/src/apps/work/src/lib/components/BillingAccountLineItemsModal/BillingAccountLineItemsModal.spec.tsx
@@ -177,6 +177,33 @@ describe('BillingAccountLineItemsModal', () => {
             .toBeNull()
     })
 
+    it('uses billing-account markup for locked challenge fees when challenge markup cannot be loaded', () => {
+        mockedFetchChallenge.mockRejectedValueOnce(new Error('Forbidden'))
+
+        renderModal({
+            ...baseBillingAccountDetails,
+            lockedAmounts: [
+                {
+                    amount: '28.6',
+                    date: '2026-05-12T00:00:00.000Z',
+                    externalId: '5fdf48d2-811f-4914-b713-9e5f423c907d',
+                    externalName: 'Copilot and Admin with reviews',
+                    externalType: 'CHALLENGE',
+                },
+            ],
+            lockedBudget: 28.6,
+            markup: 0.33,
+            totalBudgetRemaining: 971.4,
+        })
+
+        expect(screen.getAllByText('$28.60'))
+            .toHaveLength(2)
+        expect(screen.getByText('$9.44'))
+            .toBeTruthy()
+        expect(screen.queryByText('-'))
+            .toBeNull()
+    })
+
     it('removes challenge markup once from consumed challenge charges before showing member payments', async () => {
         renderModal({
             ...baseBillingAccountDetails,
diff --git a/src/apps/work/src/lib/components/BillingAccountLineItemsModal/BillingAccountLineItemsModal.tsx b/src/apps/work/src/lib/components/BillingAccountLineItemsModal/BillingAccountLineItemsModal.tsx
index 8849d0d81..3aecd2cde 100644
--- a/src/apps/work/src/lib/components/BillingAccountLineItemsModal/BillingAccountLineItemsModal.tsx
+++ b/src/apps/work/src/lib/components/BillingAccountLineItemsModal/BillingAccountLineItemsModal.tsx
@@ -272,10 +272,11 @@ async function fetchChallengeDetailsById(
  * @param item Billing-account line item being displayed.
  * @param billingAccountDetails Billing account detail payload.
  * @param challengeDetailsById Hydrated challenge details, or `undefined` while loading.
- * @returns Challenge-specific markup, billing-account fallback for legacy
- * rows, or `undefined` when the challenge row is still being hydrated.
+ * @returns Challenge-specific markup when available, otherwise the billing-account markup fallback.
  * @remarks Canonical challenge rows use challenge billing markup so `0` markup
- * challenges do not inherit the billing account default fee.
+ * challenges do not inherit the billing account default fee once hydrated. The
+ * billing-account fallback keeps locked rows from showing a blank fee when
+ * challenge hydration is unavailable.
  */
 function getLineItemChallengeMarkup(
     item: BillingAccountLineItem,
@@ -291,6 +292,7 @@ function getLineItemChallengeMarkup(
     }
 
     return challengeDetailsById?.get(challengeId)?.billing?.markup
+        ?? billingAccountDetails.markup
 }
 
 /**