Merge pull request Expensify#88580 from Expensify/claude-fixTaxRateDefaultFallback

Author: youssef-lr

src/libs/TransactionUtils/index.ts

@@ -2144,9 +2144,13 @@ function getWorkspaceTaxesSettingsName(policy: OnyxEntry<Policy>, taxCode: strin
 function getTaxName(policy: OnyxEntry<Policy>, transaction: OnyxEntry<Transaction>, shouldFallbackToValue = false) {
     const defaultTaxCode = getDefaultTaxCode(policy, transaction);
 
-    // transaction?.taxCode may be an empty string
+    // Only fall back to the default tax code when tax tracking is enabled on the policy.
+    // When taxes are disabled and the user deletes a tax, taxCode becomes undefined (the API returns null, which Onyx strips).
+    // Without this check, getTaxName would fall back to defaultTaxCode and display the default tax rate instead of showing empty.
+    // We use || instead of ?? because taxCode may be an empty string, which should also trigger the fallback.
     // eslint-disable-next-line @typescript-eslint/prefer-nullish-coalescing
-    const taxRate = Object.values(transformedTaxRates(policy, transaction)).find((rate) => rate.code === (transaction?.taxCode || defaultTaxCode));
+    const effectiveTaxCode = transaction?.taxCode || (policy?.tax?.trackingEnabled ? defaultTaxCode : undefined);
+    const taxRate = effectiveTaxCode ? Object.values(transformedTaxRates(policy, transaction)).find((rate) => rate.code === effectiveTaxCode) : undefined;
 
     if (shouldFallbackToValue && transaction?.taxValue !== undefined && taxRate?.value !== transaction?.taxValue) {
         return transaction?.taxValue;

tests/unit/TransactionUtilsTest.ts

@@ -1829,6 +1829,7 @@ describe('TransactionUtils', () => {
     describe('getTaxRateTitle', () => {
         const policy: Policy = {
             ...createRandomPolicy(0),
+            tax: {trackingEnabled: true},
             taxRates: CONST.DEFAULT_TAX,
         };
 
@@ -1892,6 +1893,22 @@ describe('TransactionUtils', () => {
             expect(result).toBe('Tax exempt (0%) • Default');
         });
 
+        it('should return empty string when trackingEnabled is false and transaction has no taxCode', () => {
+            const policyWithTrackingDisabled: Policy = {
+                ...createRandomPolicy(0),
+                tax: {trackingEnabled: false},
+                taxRates: CONST.DEFAULT_TAX,
+            };
+            const transaction = generateTransaction({
+                taxCode: undefined,
+                taxValue: undefined,
+            });
+
+            const result = TransactionUtils.getTaxRateTitle(policyWithTrackingDisabled, transaction, false, undefined);
+
+            expect(result).toBe('');
+        });
+
         it('should return empty string when policy is undefined', () => {
             const transaction = generateTransaction({
                 taxCode: 'id_TAX_RATE_1',