Fix: resolve step-page policy from the selected workspace participant

src/components/MoneyRequestConfirmationList/DistanceRequestController.tsx

@@ -23,6 +23,7 @@ import ONYXKEYS from '@src/ONYXKEYS';
 import type {Policy, Transaction} from '@src/types/onyx';
 import type {Participant} from '@src/types/onyx/IOU';
 import type {Unit} from '@src/types/onyx/Policy';
+import {isEmptyObject} from '@src/types/utils/EmptyObject';
 
 import type {OnyxEntry} from 'react-native-onyx';
 
@@ -100,11 +101,24 @@ function DistanceRequestController({
         // We want this effect to run when the transaction is moving from Self DM to an expense chat, or when the policy changes
         const isPolicyChanged = prevPolicy?.id !== policy?.id;
         const didSwitchPolicy = !!prevPolicy?.id && prevPolicy.id !== policy?.id;
-        if (!transactionID || !isDistanceRequest || !isPolicyExpenseChat || (!isMovingTransactionFromTrackExpense && !isPolicyChanged)) {
+        const errorKey = 'iou.error.invalidRate';
+
+        if (!transactionID || !isDistanceRequest) {
+            return;
+        }
+
+        // Moving the expense back to the self DM (or to a P2P recipient) leaves no workspace to validate against, so a
+        // rate error raised for the workspace it just left no longer applies. It has to be cleared here: every branch
+        // below is workspace-specific, so nothing else would ever take the message off the screen.
+        if (!isPolicyExpenseChat) {
+            clearFormErrors([errorKey]);
+            return;
+        }
+
+        if (!isMovingTransactionFromTrackExpense && !isPolicyChanged) {
             return;
         }
 
-        const errorKey = 'iou.error.invalidRate';
         const policyRates = DistanceRequestUtils.getMileageRates(policy);
 
         if (didSwitchPolicy && transaction?.comment?.customUnit?.rateAutoUpdated) {
@@ -125,6 +139,13 @@ function DistanceRequestController({
             return;
         }
 
+        // The workspace's custom units can still be loading at this point: selecting a participant resolves the new
+        // policy before Onyx has its rates, so validating now would flash an error that clears itself a moment later.
+        // With no rates to compare against we cannot tell whether the selected rate is valid - wait for the next run.
+        if (isEmptyObject(policyRates)) {
+            return;
+        }
+
         // If none of the above conditions are met, display the rate error
         setFormError(errorKey);
     }, [

src/hooks/usePolicyForTransaction.ts

@@ -1,6 +1,8 @@
+import {getSelectedWorkspacePolicyID} from '@libs/IOUUtils';
 import {getPolicyByCustomUnitID} from '@libs/PolicyUtils';
 import {isExpenseUnreported} from '@libs/TransactionUtils';
 
+import type {IOUAction} from '@src/CONST';
 import CONST from '@src/CONST';
 import ONYXKEYS from '@src/ONYXKEYS';
 import type {Policy, Transaction} from '@src/types/onyx';
@@ -18,7 +20,7 @@ type UsePolicyForTransactionParams = {
     reportPolicyID: string | undefined;
 
     /** The current action being performed */
-    action: string;
+    action: IOUAction;
 
     /** The type of IOU (split, track, submit, etc.) */
     iouType: string;
@@ -46,11 +48,17 @@ function usePolicyForTransaction({
 
     const [customUnitPolicy] = useOnyx(ONYXKEYS.COLLECTION.POLICY, {selector: (policies: OnyxCollection<Policy>) => getPolicyByCustomUnitID(transaction, policies)});
 
-    const [reportPolicy] = useOnyx(`${ONYXKEYS.COLLECTION.POLICY}${reportPolicyID}`);
+    // The route report can lag behind the workspace the user actually picked. The in-place "To" picker on the
+    // confirmation page rewrites the transaction participants but leaves the route on the report the flow started
+    // from - the self-DM, whose policyID is the '_FAKE_' placeholder. Resolving the picked workspace here means
+    // every step page reached from the confirmation reads the same policy, instead of each one re-deriving it.
+    const resolvedPolicyID = getSelectedWorkspacePolicyID(transaction, action) ?? reportPolicyID;
+
+    const [reportPolicy] = useOnyx(`${ONYXKEYS.COLLECTION.POLICY}${resolvedPolicyID}`);
     // Fall back to the draft policy from Onyx so callers that don't explicitly pass one still resolve a
     // freshly created draft workspace (e.g. "Submit to my employer" with no existing workspace). Real
     // policies always take precedence below, so this only kicks in while the workspace is still a draft.
-    const [policyDraftFromOnyx] = useOnyx(`${ONYXKEYS.COLLECTION.POLICY_DRAFTS}${reportPolicyID}`);
+    const [policyDraftFromOnyx] = useOnyx(`${ONYXKEYS.COLLECTION.POLICY_DRAFTS}${resolvedPolicyID}`);
     const policyDraft = policyDraftProp ?? policyDraftFromOnyx;
 
     const isUnreportedExpense = isExpenseUnreported(transaction);

src/pages/iou/request/step/IOURequestStepConfirmation.tsx

@@ -27,6 +27,7 @@ import useOnyx from '@hooks/useOnyx';
 import useOptimisticDraftTransactions from '@hooks/useOptimisticDraftTransactions';
 import useParticipantsPolicies from '@hooks/useParticipantsPolicies';
 import usePersonalPolicy from '@hooks/usePersonalPolicy';
+import usePolicyForMovingExpenses from '@hooks/usePolicyForMovingExpenses';
 import usePolicyForTransaction from '@hooks/usePolicyForTransaction';
 import usePreMountDestination from '@hooks/usePreMountDestination';
 import usePrivateIsArchivedMap from '@hooks/usePrivateIsArchivedMap';
@@ -254,6 +255,7 @@ function IOURequestStepConfirmationContent({
     const isTimeRequest = requestType === CONST.IOU.REQUEST_TYPE.TIME;
     const [lastLocationPermissionPrompt] = useOnyx(ONYXKEYS.NVP_LAST_LOCATION_PERMISSION_PROMPT);
     const [lastSelectedDistanceRates] = useOnyx(ONYXKEYS.NVP_LAST_SELECTED_DISTANCE_RATES);
+    const {policyForMovingExpenses} = usePolicyForMovingExpenses();
     const [introSelected] = useOnyx(ONYXKEYS.NVP_INTRO_SELECTED);
     const isLookingAroundUser = isLookingAroundSearchRoutingActive(introSelected?.choice === CONST.ONBOARDING_CHOICES.LOOKING_AROUND, isOffline);
     const privateIsArchivedMap = usePrivateIsArchivedMap();
@@ -440,6 +442,29 @@ function IOURequestStepConfirmationContent({
             if (shouldKeepOnSelfDM) {
                 setMoneyRequestParticipantsFromReport(activeTransactionID, selfDMReport, currentUserPersonalDetails.accountID);
                 setTransactionReport(activeTransactionID, {reportID: CONST.REPORT.UNREPORTED_REPORT_ID}, true);
+
+                // The rate the expense picked up from a workspace does not exist outside it, so leaving it in place
+                // makes the Rate field read "Pending..." and the amount go blank once the expense is back on the self
+                // DM. Re-resolve the rate the self DM itself uses, the same way starting a track distance expense does.
+                if (isDistanceRequest) {
+                    const selfDMRateID = DistanceRequestUtils.getCustomUnitRateID({
+                        reportID: selfDMReport?.reportID,
+                        isPolicyExpenseChat: false,
+                        isTrackDistanceExpense: true,
+                        policy: policyForMovingExpenses,
+                        lastSelectedDistanceRates,
+                        expenseDate: transaction?.created,
+                    });
+                    setCustomUnitRateID(
+                        activeTransactionID,
+                        selfDMRateID,
+                        transaction,
+                        policyForMovingExpenses,
+                        false,
+                        policyForMovingExpenses?.outputCurrency ?? personalPolicy?.outputCurrency,
+                    );
+                }
+
                 if (iouType !== CONST.IOU.TYPE.TRACK) {
                     navigation.setParams({iouType: CONST.IOU.TYPE.TRACK});
                 }
@@ -527,6 +552,7 @@ function IOURequestStepConfirmationContent({
             blockDistanceRequestIfNeeded,
             getCurrencyDecimals,
             policyID,
+            policyForMovingExpenses,
         ],
     );
 

tests/unit/components/MoneyRequestConfirmationList/DistanceRequestController.test.tsx

@@ -5,7 +5,7 @@ import DistanceRequestController from '@components/MoneyRequestConfirmationList/
 import DistanceRequestUtils from '@libs/DistanceRequestUtils';
 
 import CONST from '@src/CONST';
-import type {Transaction} from '@src/types/onyx';
+import type {Policy, Transaction} from '@src/types/onyx';
 
 import React from 'react';
 
@@ -116,4 +116,89 @@ describe('DistanceRequestController', () => {
             }),
         );
     });
+
+    describe('rate validation when the selected workspace changes', () => {
+        const RATE_ERROR = 'iou.error.invalidRate';
+
+        /** A workspace whose distance rates have not arrived from Onyx yet. */
+        const policyWithoutRates = createMock<Policy>({id: 'workspaceB', customUnits: {}});
+
+        /** A loaded workspace whose only rate matches neither the selected rate ID nor its value/unit (the unit comes from the custom unit attributes). */
+        const policyWithUnrelatedRate = createMock<Policy>({
+            id: 'workspaceB',
+            customUnits: {
+                unitID: {
+                    customUnitID: 'unitID',
+                    name: CONST.CUSTOM_UNITS.NAME_DISTANCE,
+                    attributes: {unit: CONST.CUSTOM_UNITS.DISTANCE_UNIT_KILOMETERS},
+                    enabled: true,
+                    rates: {
+                        rateB: {customUnitRateID: 'rateB', rate: 999, currency: CONST.CURRENCY.USD, enabled: true, name: 'Other rate'},
+                    },
+                },
+            },
+        });
+
+        const renderController = ({
+            policy,
+            isPolicyExpenseChat,
+            setFormError,
+            clearFormErrors,
+        }: {
+            policy: Policy | undefined;
+            isPolicyExpenseChat: boolean;
+            setFormError: jest.Mock;
+            clearFormErrors: jest.Mock;
+        }) =>
+            render(
+                <DistanceRequestController
+                    transactionID="txn1"
+                    transaction={transaction}
+                    policy={policy}
+                    isDistanceRequest
+                    isManualDistanceRequest={false}
+                    isPolicyExpenseChat={isPolicyExpenseChat}
+                    isMovingTransactionFromTrackExpense={false}
+                    isReadOnly={false}
+                    isTypeSplit={false}
+                    customUnitRateID="rateFromAnotherWorkspace"
+                    mileageRate={{rate: 67, unit: CONST.CUSTOM_UNITS.DISTANCE_UNIT_MILES, currency: CONST.CURRENCY.USD}}
+                    rate={67}
+                    unit={CONST.CUSTOM_UNITS.DISTANCE_UNIT_MILES}
+                    currency={CONST.CURRENCY.USD}
+                    distance={DistanceRequestUtils.convertToDistanceInMeters(4, CONST.CUSTOM_UNITS.DISTANCE_UNIT_MILES)}
+                    distanceRequestAmount={201}
+                    shouldCalculateDistanceAmount={false}
+                    currentUserAccountID={1}
+                    isDistanceRequestWithPendingRoute={false}
+                    hasRoute
+                    defaultMileageRateCustomUnitRateID={undefined}
+                    selectedParticipants={[]}
+                    selectedParticipantsProp={[]}
+                    setFormError={setFormError}
+                    clearFormErrors={clearFormErrors}
+                />,
+            );
+
+        it('does not flag the rate while the newly selected workspace still has no rates loaded', () => {
+            const setFormError = jest.fn();
+            renderController({policy: policyWithoutRates, isPolicyExpenseChat: true, setFormError, clearFormErrors: jest.fn()});
+
+            expect(setFormError).not.toHaveBeenCalled();
+        });
+
+        it('still flags the rate once the workspace rates are loaded and none of them match', () => {
+            const setFormError = jest.fn();
+            renderController({policy: policyWithUnrelatedRate, isPolicyExpenseChat: true, setFormError, clearFormErrors: jest.fn()});
+
+            expect(setFormError).toHaveBeenCalledWith(RATE_ERROR);
+        });
+
+        it('clears a workspace rate error once the expense is no longer on a workspace chat', () => {
+            const clearFormErrors = jest.fn();
+            renderController({policy: undefined, isPolicyExpenseChat: false, setFormError: jest.fn(), clearFormErrors});
+
+            expect(clearFormErrors).toHaveBeenCalledWith([RATE_ERROR]);
+        });
+    });
 });