Fix #476 : delete dangling build artifacts before migration

[pierrotsmnrd]

Fix #476 : Delete dangling build artifacts before migration.

[costrouc]

@pierrotsmnrd

[costrouc]

@pierrotsmnrd going forward I was wondering what adjustments would be needed in the orm model?

[pierrotsmnrd]

@costrouc my understanding is that nothing else is necessary.

This line ensures the on-delete cascade from build to build_artifacts and was added 2 years ago.

So :

• Either there's something we haven't spot yet in the codebase that leads to dangling build_artifacts (but what ?)
• Or the case we encountered is the result of an old install of conda-store, where builds has been deleted before the on-delete cascade was added. Considering this identified case is using an old Postgres 11.14, this hypothesis could make sense. Or maybe they tinkered with their data and we don't know.