Google People API detect merged contacts with syncToken - previousResourceNames not included - google-people-api

Question

I am using the people API to allow users to create entities in my system from their google contacts, via the people API, and am storing the resourceName (i.e 'people/c7760106965272617307') to keep track of the google contact the entity was created from.
I want to be able periodically update the entities to match what is in google. i.e. if the contact updates the phone number the entity gets the updated phone number. So am a calling the list API passing the sync token to get the contacts that have changed since the last call. This works for updates, edits and deletes but I can't find a way to detect when two contacts have been merged in google contacts.
The docs state:
https://developers.google.com/people/api/rest/v1/people#Person.PersonMetadata
previousResourceNames[] Any former resource names this person has had.
Populated only for connections.list requests that include a sync
token.
So if I:
- Call the list API requesting a sync token
- Create Contact A and Contact B
- Call the list API passing the sync token, then I get just the two created contacts and a new sync token:
{
"resourceName": "people/c1465347538402693914",
"etag": "%EgcBAj0JPjcuGgQBAgUHIgxab0lZTFBvUU43bz0=",
"metadata": {
"sources": [
{
"type": "CONTACT",
"id": "1455f5d28afc531a",
"etag": "#ZoIYLPoQN7o=",
"updateTime": "2020-02-26T15:35:34.021Z"
}
],
"objectType": "PERSON"
},
"names": [
{
"metadata": {
"primary": true,
"source": {
"type": "CONTACT",
"id": "1455f5d28afc531a"
}
},
"displayName": "Contact A",
"familyName": "A",
"givenName": "Contact",
"displayNameLastFirst": "A, Contact"
}
]
},
{
"resourceName": "people/c4555919836853785218",
"etag": "%EgcBAj0JPjcuGgQBAgUHIgx2WmJHUUtjNTcxQT0=",
"metadata": {
"sources": [
{
"type": "CONTACT",
"id": "3f39e0f40cd35282",
"etag": "#vZbGQKc571A=",
"updateTime": "2020-02-26T15:35:44.056Z"
}
],
"objectType": "PERSON"
},
"names": [
{
"metadata": {
"primary": true,
"source": {
"type": "CONTACT",
"id": "3f39e0f40cd35282"
}
},
"displayName": "Contact B",
"familyName": "B",
"givenName": "Contact",
"displayNameLastFirst": "B, Contact"
}
}
If I then merge the two contacts, and then call the API passing the new sync token i get:
{
"resourceName": "people/c4555919836853785218",
"etag": "%EgcBAj0JPjcuGgQBAgUHIgxqNlFVYnIwaU9vVT0=",
"metadata": {
"sources": [
{
"type": "CONTACT",
"id": "3f39e0f40cd35282"
}
],
"deleted": true,
"objectType": "PERSON"
}
}
So TDLR; I can find out one of the contacts were deleted, but not that it was merged into another contact.
It seems like the previousResourceNames[] field would do exactly what I want, but I can't seem to make it return in the data, either on the try the API function on the docs:
https://developers.google.com/people/api/rest/v1/people.connections/list
or using the below nodjs code:
const service = google.people({version: 'v1', auth: authClient});
const result = await service.people.connections.list({
resourceName: 'people/me',
personFields: 'names,emailAddresses,phoneNumbers,metadata',
//requestSyncToken: true
syncToken: "insert token here"
});
console.info("Google Returned", JSON.stringify(result.data, null, 4));
I wonder if i need to grant extra scopes, or something else in the requested person fields.
Scopes Requested:
'https://www.googleapis.com/auth/contacts',
'https://www.googleapis.com/auth/userinfo.email',
'https://www.googleapis.com/auth/userinfo.profile'