[BUG] API returns error when updating existing mongo cluster

API Spec link

https://github.com/Azure/azure-rest-api-specs/blob/main/specification/mongocluster/resource-manager/Microsoft.DocumentDB/stable/2024-07-01/mongoCluster.json#L279

API Spec version

2024-07-01

Describe the bug

When updating an existing mongocluster through the MongoClusters_CreateOrUpdate API using the response returned by the MongoClusters_Get API, an error was received, the update operation failed.

Expected behavior

Update should succeed. The API shouldn't care if this is set (like most of the other Azure APIs).

Actual behavior

Update failed, the API returns the following error.

{"error":{"code":"bad_request","message":"Found schema errors for api-version 2024-07-01. Errors: The property '#/systemData' of type null did not match the following type: object in schema 25debcc2-6915-5536-9566-a2ecd765b755"}}

Reproduction Steps

Step1: Get an existing mongocluster which compute tier is free.

GET /subscriptions/.../resourceGroups/acctestRG-241101100238280187/providers/Microsoft.DocumentDB/mongoClusters/acctest-mc241101100238280187?api-version=2024-07-01 HTTP/1.1
X-Ms-Correlation-Request-Id: 95471b42-6c6b-a3e0-af45-b43d8cc12b27

AzureRM Response:
HTTP/2.0 200 OK
Date: Fri, 01 Nov 2024 02:12:58 GMT
X-Ms-Correlation-Request-Id: 95471b42-6c6b-a3e0-af45-b43d8cc12b27

{
  "id": "/subscriptions/.../resourceGroups/acctestRG-241101100238280187/providers/Microsoft.DocumentDB/mongoClusters/acctest-mc241101100238280187",
  "name": "acctest-mc241101100238280187",
  "type": "Microsoft.DocumentDB/mongoClusters",
  "tags": {
  },
  "location": "eastus",
  "systemData": {
    "createdAt": "2024-11-01T02:03:51.3222716Z",
    "createdBy": "e0228b2d-03d1-4463-b866-a871d418a0be",
    "createdByType": "Application",
    "lastModifiedAt": "2024-11-01T02:03:51.3222716Z",
    "lastModifiedBy": "e0228b2d-03d1-4463-b866-a871d418a0be",
    "lastModifiedByType": "Application"
  },
  "properties": {
    "provisioningState": "Succeeded",
    "clusterStatus": "Ready",
    "administrator": {
      "userName": "admintest"
    },
    "serverVersion": "6.0",
    "compute": {
      "tier": "Free"
    },
    "storage": {
      "sizeGb": 32
    },
    "sharding": {
      "shardCount": 1
    },
    "highAvailability": {
      "targetMode": "Disabled"
    },
    "connectionString": "mongodb+srv://<user>:<password>@acctest-mc241101100238280187.mongocluster.cosmos.azure.com/?tls=true&authMechanism=SCRAM-SHA-256&retrywrites=false&maxIdleTimeMS=120000",
    "backup": {
    },
    "privateEndpointConnections": [

    ],
    "publicNetworkAccess": "Enabled",
    "infrastructureVersion": "1.0"
  }
}

Step2: Using the data response in Step 1, update only the compute tier from free to M30 .

PUT /subscriptions/.../resourceGroups/acctestRG-241101100238280187/providers/Microsoft.DocumentDB/mongoClusters/acctest-mc241101100238280187?api-version=2024-07-01 HTTP/1.1
X-Ms-Correlation-Request-Id: 95471b42-6c6b-a3e0-af45-b43d8cc12b27

{
   "id":"/subscriptions/.../resourceGroups/acctestRG-241101100238280187/providers/Microsoft.DocumentDB/mongoClusters/acctest-mc241101100238280187",
   "location":"eastus",
   "name":"acctest-mc241101100238280187",
   "properties":{
      "administrator":{
         "userName":"adminTest"
      },
      "backup":{

      },
      "clusterStatus":"Ready",
      "compute":{
         "tier":"M30"
      },
      "connectionString":"mongodb+srv://\u003cuser\u003e:\u003cpassword\u003e@acctest-mc241101100238280187.mongocluster.cosmos.azure.com/?tls=true\u0026authMechanism=SCRAM-SHA-256\u0026retrywrites=false\u0026maxIdleTimeMS=120000",
      "highAvailability":{
         "targetMode":"Disabled"
      },
      "infrastructureVersion":"1.0",
      "privateEndpointConnections":[

      ],
      "provisioningState":"Succeeded",
      "publicNetworkAccess":"Enabled",
      "serverVersion":"6.0",
      "sharding":{
         "shardCount":1
      },
      "storage":{
         "sizeGb":32
      }
   },
   "systemData":null,
   "tags":{

   },
   "type":"Microsoft.DocumentDB/mongoClusters"
}

AzureRM Response:
HTTP/2.0 400 Bad Request
Date: Fri, 01 Nov 2024 02:13:01 GMT
X-Ms-Correlation-Request-Id: 95471b42-6c6b-a3e0-af45-b43d8cc12b27

{"error":{"code":"bad_request","message":"Found schema errors for api-version 2024-07-01. Errors: The property '#/systemData' of type null did not match the following type: object in schema 25debcc2-6915-5536-9566-a2ecd765b755"}}

Environment

No response

Azure / azure-rest-api-specs