Problem Statement/Rationale

It is not possible to perform a mongorestore after custom users was created.

Steps to Reproduce

• 1. MongoDB shell*
     db.test.insert( { item: "card1", qty: 15 } )
     db.test.insert( { item: "card2", qty: 30 } )
     db.test.insert( { item: "card3", qty: 45 } )
     db.test.insert( { item: "card4", qty: 60 } )
     db.test.insert( { item: "card5", qty: 75 } )
     *db.createUser({user: "testUser", pwd: "testpwd", roles: [ {role: "userAdminAnyDatabase" , db:"admin"}

     ]})*

• 1. bash shell*
     mongodump

• 1. MongoDB shell*
     db.test.deleteMany({})
     db.dropUser("testUser")

• 1. bash shell*
     mongorestore --drop dump
     2021-08-19T09:11:05.021+0000 preparing collections to restore from
     2021-08-19T09:11:05.026+0000 reading metadata for test.test from dump/test/test.metadata.json
     2021-08-19T09:11:05.028+0000 dropping collection test.test before restoring
     2021-08-19T09:11:05.058+0000 restoring test.test from dump/test/test.bson
     2021-08-19T09:11:05.069+0000 finished restoring test.test (5 documents, 0 failures)
     2021-08-19T09:11:05.070+0000 restoring users from dump/admin/system.users.bson
     2021-08-19T09:11:05.111+0000 Failed: restore error: error running merge command: (Location40414) BSON field '_mergeAuthzCollections.tempRolesCollection' is missing but a required field
     2021-08-19T09:11:05.111+0000 5 document(s) restored successfully. 0 document(s) failed to restore.

Expected Results

The mongorestore finishes the restore successful with setting all data and users from the backup and returning an exit status of 0

Actual Results

Data gets restored but users not. mongorestore finishes with an exit status of 1

Additional Notes

• I'm not sure if this is a general MondoDB or mongorestore issue. The restore works with older versions of MongoDB (tested successful with MongoDB 4.4.8)
• Related to this [question|https://www.mongodb.com/community/forums/t/mongorestore-not-working-when-roles-are-added/120220] at the community forum