fix: recompute taxAmount on amount-only bulk edit offline

Author: LukasMod

src/libs/actions/IOU/BulkEdit.ts

@@ -168,6 +168,15 @@ function updateMultipleMoneyRequests({
         if (changes.amount !== undefined && canEditField(CONST.EDIT_REQUEST_FIELD.AMOUNT)) {
             transactionChanges.amount = changes.amount;
         }
+        // When bulk-editing amount on a taxed expense without also changing taxCode, recompute
+        // taxAmount from the transaction's existing taxCode so offline optimistic data and the
+        // queued payload stay in sync with the new amount
+        if (changes.amount !== undefined && !changes.taxCode && transaction.taxCode && supportsExpenseFields && canEditField(CONST.EDIT_REQUEST_FIELD.TAX_RATE)) {
+            const taxValue = getTaxValue(transactionPolicy, transaction, transaction.taxCode);
+            const decimals = getCurrencyDecimals(getCurrency(transaction));
+            const taxAmount = calculateTaxAmount(taxValue, Math.abs(changes.amount), decimals);
+            transactionChanges.taxAmount = convertToBackendAmount(taxAmount);
+        }
         if (changes.currency && canEditField(CONST.EDIT_REQUEST_FIELD.CURRENCY)) {
             transactionChanges.currency = changes.currency;
         }

tests/actions/IOUTest/BulkEditTest.ts

@@ -1242,6 +1242,133 @@ describe('actions/IOU/BulkEdit', () => {
             buildOptimisticSpy.mockRestore();
             canEditFieldSpy.mockRestore();
         });
+
+        it('recalculates taxAmount when bulk-editing only amount on a taxed expense', () => {
+            const transactionID = 'transaction-tax-amount-only';
+            const iouReportID = 'iou-tax-amount-only';
+            const taxCode = 'id_TAX_RATE_1';
+            const policy: Policy = {
+                ...createRandomPolicy(1, CONST.POLICY.TYPE.TEAM),
+                taxRates: CONST.DEFAULT_TAX,
+            };
+
+            const iouReport: Report = {
+                ...createRandomReport(2, undefined),
+                reportID: iouReportID,
+                policyID: policy.id,
+                type: CONST.REPORT.TYPE.EXPENSE,
+            };
+
+            const reports = {
+                [`${ONYXKEYS.COLLECTION.REPORT}${iouReportID}`]: iouReport,
+            };
+
+            const transaction: Transaction = {
+                ...createRandomTransaction(1),
+                transactionID,
+                reportID: iouReportID,
+                amount: -1000,
+                currency: CONST.CURRENCY.USD,
+                taxCode,
+                taxAmount: -48,
+            };
+            const transactions = {
+                [`${ONYXKEYS.COLLECTION.TRANSACTION}${transactionID}`]: transaction,
+            };
+
+            const canEditFieldSpy = jest.spyOn(require('@libs/ReportUtils'), 'canEditFieldOfMoneyRequest').mockReturnValue(true);
+            // eslint-disable-next-line rulesdir/no-multiple-api-calls
+            const writeSpy = jest.spyOn(API, 'write').mockImplementation(jest.fn());
+
+            updateMultipleMoneyRequests({
+                transactionIDs: [transactionID],
+                changes: {amount: -2000},
+                policy,
+                reports,
+                transactions,
+                reportActions: {},
+                policyCategories: undefined,
+                policyTags: {},
+                hash: undefined,
+                introSelected: undefined,
+                betas: undefined,
+            });
+
+            const params = writeSpy.mock.calls.at(0)?.[1] as {updates: string};
+            const updates = JSON.parse(params.updates) as {amount: number; taxAmount?: number};
+            expect(updates.amount).toBe(-2000);
+            expect(updates.taxAmount).toBe(95);
+
+            // Optimistic transaction merge should store the flipped sign for expense reports.
+            const onyxData = writeSpy.mock.calls.at(0)?.[2] as {optimisticData: Array<{key: string; value: Partial<Transaction>}>} | undefined;
+            const transactionOnyxUpdate = onyxData?.optimisticData?.find((update) => update.key === `${ONYXKEYS.COLLECTION.TRANSACTION}${transactionID}`);
+            expect(transactionOnyxUpdate?.value?.taxAmount).toBe(-95);
+
+            writeSpy.mockRestore();
+            canEditFieldSpy.mockRestore();
+        });
+
+        it('does not inject taxAmount when bulk-editing amount on a non-tax expense', () => {
+            // A transaction that has no taxCode must not have a taxAmount clobbered to 0 just
+            // because the user bulk-edited the amount — that would flip a non-tax expense into
+            // a zero-tax expense offline.
+            const transactionID = 'transaction-no-tax';
+            const iouReportID = 'iou-no-tax';
+            const policy: Policy = {
+                ...createRandomPolicy(1, CONST.POLICY.TYPE.TEAM),
+                taxRates: CONST.DEFAULT_TAX,
+            };
+
+            const iouReport: Report = {
+                ...createRandomReport(2, undefined),
+                reportID: iouReportID,
+                policyID: policy.id,
+                type: CONST.REPORT.TYPE.EXPENSE,
+            };
+
+            const reports = {
+                [`${ONYXKEYS.COLLECTION.REPORT}${iouReportID}`]: iouReport,
+            };
+
+            const transaction: Transaction = {
+                ...createRandomTransaction(1),
+                transactionID,
+                reportID: iouReportID,
+                amount: -1000,
+                currency: CONST.CURRENCY.USD,
+                taxCode: '',
+                taxAmount: undefined,
+            };
+            const transactions = {
+                [`${ONYXKEYS.COLLECTION.TRANSACTION}${transactionID}`]: transaction,
+            };
+
+            const canEditFieldSpy = jest.spyOn(require('@libs/ReportUtils'), 'canEditFieldOfMoneyRequest').mockReturnValue(true);
+            // eslint-disable-next-line rulesdir/no-multiple-api-calls
+            const writeSpy = jest.spyOn(API, 'write').mockImplementation(jest.fn());
+
+            updateMultipleMoneyRequests({
+                transactionIDs: [transactionID],
+                changes: {amount: -2000},
+                policy,
+                reports,
+                transactions,
+                reportActions: {},
+                policyCategories: undefined,
+                policyTags: {},
+                hash: undefined,
+                introSelected: undefined,
+                betas: undefined,
+            });
+
+            const params = writeSpy.mock.calls.at(0)?.[1] as {updates: string};
+            const updates = JSON.parse(params.updates) as {amount: number; taxAmount?: number};
+            expect(updates.amount).toBe(-2000);
+            expect(updates.taxAmount).toBeUndefined();
+
+            writeSpy.mockRestore();
+            canEditFieldSpy.mockRestore();
+        });
     });
 
     describe('bulk edit draft transaction', () => {