Problem upgrading NetBox 3.4.x and a plugin using search indices on new columns

[peteeckel]

See auroraresearchlab/netbox-dns#261

The problem seems to be that the upgrade of NetBox from 3.3.x to 3.4.x runs a migration that updates search indices, and the plugin adds a new column (that is indexed) in a migration that runs after the NetBox migrations, causing the NetBox migration to fail.

For this to occur, several conditions are required:

1. NetBox upgrade from 3.3.x to 3.4.x
2. A plugin uses the new SearchIndex functionality
3. The plugin's migration adds a new column to a table, which is incuded in a SearchIndex
4. That plugin is upgraded at the same time as NetBox

This creates a hen-and-egg problem: NetBox wants to reindex tables for all models, and when it comes to reindex the model's new table it just isn't there yet. If it weren't a plugin, the solution would be to make the NetBox migration netbox/extras/migrations/0083_search.py depending on the migration that creates the table, but that's obviously not an option in this case.

Is there something I missed, or is it simply a documentation issue I need to fix in the plugin (disable plugin, run NetBox migrations, enable plugin again)? I think this could happen with other plugins as well, although the conditions are certainly a bit special.

[peteeckel]

I found out that even the initial migration fails when an enabled plugin uses SearchIndex. Opened #11248.