Schema mismatch: Property '###' in class '###' is of type Link on one side and type ObjectId on the other

MongoDB Atlas App Services & Realm
1

What does this mean? It happens after I export my app with realm-cli, and then - without making changes - pushing what’s exported to my repository for automatic deployment back to my realm app. It breaks my schema.

2

Hi Eric,

This usually means there is a mismatch of types for the property between your server side schema and your client side schema.

Has the type for this property changed in your client side?

Regards
Manny

1 Like
3

Hi there

Thanks for getting back to me. I’ll need to refresh myself with this particular issue as it is a week old now. Unfortunately I don’t have the time to reproduce this myself on demand because it really slows me down.

When next I have to perform this work flow again, I’ll post the results here,

For now, from what I recall, I can reproduce it like this:
Note: I start with a working sync configuration having no sync errors on server or client.

  1. Export app configuration directory via realm-cli
  2. Set up version control for the exported directory (which I have to do every time because I haven’t figured out this other realm-cli issue
  3. Force push the unmodified directory to my repo to trigger an automatic deployment (again, that’s with unmodified source files and directory organization - it’s literally EXACTLY what realm-cli exported for me)
  4. The next time I start the client, these errors appear.

The only solution I have found is to manually delete all schemas using the Atlas UI, and then deactivating Sync, and re-enabling in development mode, running the client, turning off development mode, re-entering my permission expressions and finally activating sync.

As you can imagine this is a huge amount of time to pay for wanting to do something as simple as edit one line of code in a realm function in my own development environment, for instance.

4

Hi there,

Any input or thoughts on the above? I’m still trying to find or make a solution for this issue.

Thanks!

6

I’d like to bump this issue if possible. We’ve been seeing this happen for us, but only for a specific class, other changes or collection updates seem to work ok.

8

I’m also having this issue. Is there a quick fix to this rather than deleting the schema?

9

Hello, I encountered the exact error in a different scenario so I’m leaving a reply for anyone interested.

Essentially the issue on my end was that after I had copied the schema config from my development app over to my production app, I had missed the “Expanded relationships” for one of the schemas that was generated by Dev Mode.

The generated Expanded Relationship had the following shape and upon seeing it it instantly made sense what the “Link” in the error was referring to:

{
“integrationId”: {
“ref”: “#/relationship/mongodb-atlas/sync/integrations”,
“foreignKey”: “_id”,
“isList”: false
}
}