Do you have an example? If you're using Django's default testing framework, it normally creates a fresh database, so from the moment a new data migration is written it would be tested with the empty database scenario.
Afaiu it is possible to write RunPython operations in a way that no-ops on empty databases, e.g. starting with the equivalent of "if not Model.object.exists(): return." It is also possible with RunSQL on database backends that support conditional logic around SQL statements, or they can be easily converted to RunPython using a function that uses cursor.execute(). And if a project develops problems with past migrations, it's always possible to (carefully) edit them to include such conditions. On Fri, 9 Nov 2018 at 16:11, Dan Watson <dcwat...@gmail.com> wrote: > Hi All, > > I was wondering if anyone had any thoughts on an option to the "migrate" > command (--skip-elidable?) that would skip running elidable migrations. The > use case here is that data migrations that build up over time may act on > certain assumptions (existing tables/data) that may not be true when > migrating a new database. It seems that since they were explicitly marked > as able to be deleted when squashing, they would be safe to not run when > creating a new database. Maybe we don't go so far as to make this the > default behavior when migrating a fresh database, but an option would be > nice. I realize you could simply squash your migrations, but that's not > without penalty of code churn, testing, etc. especially when your existing > migration graph is otherwise fine (and performant). > > If there's some consensus about this being worthwhile, or at least no > strong objections to it, I can take a stab at the implementation. > > Regards, > Dan > > -- > You received this message because you are subscribed to the Google Groups > "Django developers (Contributions to Django itself)" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to django-developers+unsubscr...@googlegroups.com. > To post to this group, send email to django-developers@googlegroups.com. > Visit this group at https://groups.google.com/group/django-developers. > To view this discussion on the web visit > https://groups.google.com/d/msgid/django-developers/fba7a58a-444b-4c90-b139-151580423366%40googlegroups.com > <https://groups.google.com/d/msgid/django-developers/fba7a58a-444b-4c90-b139-151580423366%40googlegroups.com?utm_medium=email&utm_source=footer> > . > For more options, visit https://groups.google.com/d/optout. > -- Adam -- You received this message because you are subscribed to the Google Groups "Django developers (Contributions to Django itself)" group. To unsubscribe from this group and stop receiving emails from it, send an email to django-developers+unsubscr...@googlegroups.com. To post to this group, send email to django-developers@googlegroups.com. Visit this group at https://groups.google.com/group/django-developers. To view this discussion on the web visit https://groups.google.com/d/msgid/django-developers/CAMyDDM0JUEWSBJVgEnhrdXttitV%2BAqAkWoMzeSB%2BHh7mDsPbWA%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
