firestore/internal/conformance/testdata/update-prefix-3.json

{
  "tests": [
    {
      "description": "update: prefix #3",
      "comment": "In the input data, one field cannot be a prefix of another, even if the values could in principle be combined.",
      "update": {
        "docRefPath": "projects/projectID/databases/(default)/documents/C/d",
        "jsonData": "{\"a\": {\"b\": 1}, \"a.d\": 2}",
        "isError": true
      }
    }
  ]
}