(cherry picked from commit 24954283)

Julian authored 3 years ago and Jonathan Weth committed 3 years ago

(cherry picked from commit e5b82ac1)

(cherry picked from commit f7632570)

(cherry picked from commit 6f774c1d)

(cherry picked from commit 4c705a68)

(cherry picked from commit 73f0750a)

Jonathan Weth authored 3 years ago and Nik | Klampfradler committed 3 years ago

(cherry picked from commit 528e23f0)

Together with 18544e06, updating the existing
migration is safe, because

 a) if the migration failed somewhere due to the multiple leaf nodes, it was
    never applied, and changing it is safe;
 b) if it succeeded, it will be renamed to 0008_ later, and thus
    re-applied