fix: 400 is correct error code for computing slot for past booking (#22574)

* fix

* add test

packages/trpc/server/routers/viewer/slots/util.test.ts

@@ -0,0 +1,45 @@
+import { describe, it, expect } from "vitest";
+
+import { BookingDateInPastError, isTimeOutOfBounds } from "@calcom/lib/isOutOfBounds";
+
+import { TRPCError } from "@trpc/server";
+
+describe("BookingDateInPastError handling", () => {
+  it("should convert BookingDateInPastError to TRPCError with BAD_REQUEST code", () => {
+    const testFilteringLogic = () => {
+      const mockSlot = {
+        time: "2024-05-20T12:30:00.000Z", // Past date
+        attendees: 1,
+      };
+
+      const mockEventType = {
+        minimumBookingNotice: 0,
+      };
+
+      const isFutureLimitViolationForTheSlot = false; // Mock this to false
+
+      let isOutOfBounds = false;
+      try {
+        // This will throw BookingDateInPastError for past dates
+        isOutOfBounds = isTimeOutOfBounds({
+          time: mockSlot.time,
+          minimumBookingNotice: mockEventType.minimumBookingNotice,
+        });
+      } catch (error) {
+        if (error instanceof BookingDateInPastError) {
+          throw new TRPCError({
+            code: "BAD_REQUEST",
+            message: error.message,
+          });
+        }
+        throw error;
+      }
+
+      return !isFutureLimitViolationForTheSlot && !isOutOfBounds;
+    };
+
+    // This should throw a TRPCError with BAD_REQUEST code
+    expect(() => testFilteringLogic()).toThrow(TRPCError);
+    expect(() => testFilteringLogic()).toThrow("Attempting to book a meeting in the past.");
+  });
+});

packages/trpc/server/routers/viewer/slots/util.ts

@@ -35,6 +35,7 @@ import {
   calculatePeriodLimits,
   isTimeOutOfBounds,
   isTimeViolatingFutureLimit,
+  BookingDateInPastError,
 } from "@calcom/lib/isOutOfBounds";
 import logger from "@calcom/lib/logger";
 import { isRestrictionScheduleEnabled } from "@calcom/lib/restrictionSchedule";
@@ -1313,6 +1314,22 @@ export class AvailableSlotsService {
             periodLimits,
           });
 
+          let isOutOfBounds = false;
+          try {
+            isOutOfBounds = isTimeOutOfBounds({
+              time: slot.time,
+              minimumBookingNotice: eventType.minimumBookingNotice,
+            });
+          } catch (error) {
+            if (error instanceof BookingDateInPastError) {
+              throw new TRPCError({
+                code: "BAD_REQUEST",
+                message: error.message,
+              });
+            }
+            throw error;
+          }
+
           if (isFutureLimitViolationForTheSlot) {
             foundAFutureLimitViolation = true;
           }
@@ -1320,7 +1337,7 @@ export class AvailableSlotsService {
           return (
             !isFutureLimitViolationForTheSlot &&
             // TODO: Perf Optimization: Slots calculation logic already seems to consider the minimum booking notice and past booking time and thus there shouldn't be need to filter out slots here.
-            !isTimeOutOfBounds({ time: slot.time, minimumBookingNotice: eventType.minimumBookingNotice })
+            !isOutOfBounds
           );
         });