mimetype migrations warning after fresh Docker install

[marscat5]

After performing a fresh installation of Nextcloud using the official Docker image, I was presented with the following warning in the system overview:

One or more mimetype migrations are available. Occasionally new mimetypes are added to better handle certain file types. Migrating the mimetypes take a long time on larger instances so this is not done automatically during upgrades. Use the command occ maintenance:repair --include-expensive to perform the migrations

To resolve this, I had to manually run:
docker exec -itu www-data <container_name> ./occ maintenance:repair --include-expensive

Expected Behavior

A fresh installation of Nextcloud - especially via Docker, where users expect automation - should result in a fully working, clean state without requiring manual execution of (expensive) maintenance tasks, not immediately after first deployment.

Proposed Solution

Automatically perform necessary mimetype migrations during the initial setup phase (especially for new installs).

Impact

• New users may be confused by warnings on a fresh install
• Adds friction to automation, CI/CD, and reproducible deployment scenarios

Thanks for your attention, and for the work on maintaining the Docker image!

[joshtrichards]

What version?

However, if this is occurring still, it needs to be dealt with upstream rather than in the image.

I'm not sure how this would be happening, however, outside of upgrades or apps (e.g. an app being installed immediately post installation that adds their own mimetypes).

[marscat5]

Thank you for looking into this.
I just tested it with a fresh installation which gave me Nextcloud 31.0.8 and still got the warning.
For reference see attached my slightly modified compose file (passwords, IP-addresses and domain names changed/removed):

compose.yml