There is no need to wrap the save() call in transaction.atomic() as
it's already done down the call stack in Model.save_base().

Thanks to Trac aliases gerricom for the report, raphaelmerx for the
attempts to reproduce and Sergey Fedoseev and Tim for the review.

Refs #16891

Thanks Ben Kraft for the report, and Simon Charette for the review.

Thanks to bmispelon and uruz for the initial patch.

Thanks hop for the report and patch.

Thanks to Emanuele Palazzetti for the help.

The test creates and deletes a model in the same migration, and the model
had an AutoField. On Oracle, AutoField's are set up using deferred SQL, which
in this case was trying to modify a table after it had dbeen removed.

Referencing URLs by dotted path is a stronger convention than
importing the URLs.

Fixed #25672 -- Clarified why related ManyToManyFields with a custom intermediate model disable the remove() method.

Due to randomness of garbage collection with geometry objects, it's
easier to simply ignore AttributeError/TypeError generally raised when
parts of objects are already garbage-collected.
Thanks Sergey Fedoseev and Tim Graham for reviewing the patch.

URLValidator now validates the maximum length of a hostname and the
maximum length of all labels inside the hostname.

Thanks Justin Abrahms for the report.