chore: improve check for file

Author: kevinkim-ogp

packages/backend/src/apps/aisay/common/schema.ts

@@ -5,10 +5,18 @@ import { parseS3Id } from '@/helpers/s3'
 import { DOCUMENT_TYPES } from './constants'
 
 export const fileSchema = z.string().transform((value, context) => {
+  if (!value) {
+    context.addIssue({
+      code: z.ZodIssueCode.custom,
+      message: 'No file was provided',
+      fatal: true,
+    })
+    return z.NEVER
+  }
   if (!parseS3Id(value)) {
     context.addIssue({
       code: z.ZodIssueCode.custom,
-      message: `No file was provided`,
+      message: `${value} is not a S3 ID.`,
       fatal: true,
     })
     return z.NEVER