fix: preserve req.file across nested Local API calls from hooks

packages/payload/src/collections/operations/local/create.ts

@@ -217,7 +217,13 @@ export async function createLocal<
 
   const req = await createLocalReq(options as CreateLocalReqOptions, payload)
 
-  req.file = file ?? (await getFileByPath(filePath!))
+  // Only assign `req.file` when a file or filePath was explicitly passed to this operation.
+  // Otherwise, this would overwrite (and drop) a file reference that was already set on `req`
+  // by an earlier upload operation, e.g. when a hook passes the original `req` through to a
+  // nested Local API call. See https://github.com/payloadcms/payload/issues/15975
+  if (file || filePath) {
+    req.file = file ?? (await getFileByPath(filePath!))
+  }
 
   return createOperation<TSlug, TSelect>({
     collection,

packages/payload/src/collections/operations/local/update.ts

@@ -250,7 +250,14 @@ async function updateLocal<
   }
 
   const req = await createLocalReq(options as CreateLocalReqOptions, payload)
-  req.file = file ?? (await getFileByPath(filePath!))
+
+  // Only assign `req.file` when a file or filePath was explicitly passed to this operation.
+  // Otherwise, this would overwrite (and drop) a file reference that was already set on `req`
+  // by an earlier upload operation, e.g. when a hook passes the original `req` through to a
+  // nested Local API call. See https://github.com/payloadcms/payload/issues/15975
+  if (file || filePath) {
+    req.file = file ?? (await getFileByPath(filePath!))
+  }
 
   const args = {
     id,

test/uploads/int.spec.ts

@@ -1808,6 +1808,37 @@ describe('Collections - Uploads', () => {
     })
   })
 
+  describe('req.file preservation across nested Local API calls', () => {
+    it('should preserve req.file when a hook calls the Local API with the original req', async () => {
+      const filePath = path.resolve(dirname, './image.png')
+      const file = await getFileByPath(filePath)
+      file.name = 'preserve-req-file-test.png'
+
+      // Simulate `req` as it would exist on an upload request, i.e. already
+      // carrying a `file` reference before any nested Local API call is made.
+      const req = { file } as PayloadRequest
+
+      // Simulate a hook (e.g. an upload collection's afterChange) that calls
+      // the Local API on another, non-upload collection, passing the original
+      // `req` through per the docs' recommendation to preserve request context.
+      const relationDoc = await payload.create({
+        collection: relationSlug,
+        data: {},
+        req,
+      })
+
+      expect(relationDoc.id).toBeDefined()
+
+      // The original file reference on `req` must still be accessible after
+      // the nested Local API call returns, so that a subsequent hook (or an
+      // upload storage adapter) can still read it.
+      expect(req.file).toBeDefined()
+      expect(req.file?.name).toBe('preserve-req-file-test.png')
+
+      await payload.delete({ collection: relationSlug, id: relationDoc.id })
+    })
+  })
+
   describe('serverURL handling', () => {
     it('should store relative URLs in database even when serverURL is set', async () => {
       // Temporarily set serverURL for this test