Problem: the update of custom models/fields is not fully transactional, and may
potentially lead to an inconsistent database. An other problem is creating two
custom fields by writing on a model: if the second one fails, the first one has
been committed without notice. Retrying the request will give an unexpected
error (duplicate field name).
Solution: never commit in the middle of a request. If the changes have an
impact on the registry, then mark it as invalid (with a new flag), and signal
registry invalidation after everything has been committed. If the request
fails, reset the registry. Both registry and cache invalidation are handled
the same way.
Introspection attributes on function and methods were originally
prefixed with func_ or im_ e.g. im_class or func_name. For coherence with the
rest of the data model, Python 3 added dunder attributes (__func__,
__code__) and removed the old style, the dunder attributes were
backported to Python 2.6.
Use dunder attributes everywhere we're currently using func_* or im_*
attributes.
Fixers:
lib2to3.fixes.fix_funcattrs
lib2to3.fixes.fix_methodattrs
#8530
Olivier Dony