id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
35024	Creating model objects crashes on fields with database converters when RETURNING is not supported.	Mariusz Felisiak	Mariusz Felisiak	"Creating model objects crashes on fields with database converters when RETURNING is not supported. For example

{{{#!python
class GeneratedBooleanFieldModel(Model):
    value = IntegerField(null=True)
    has_value = GeneratedField(
        expression=Q(value__isnull=False),
        output_field=BooleanField(),
        db_persist=False,
    )
}}}
crashes with:
{{{
  File ""/home/jenkins/workspace/pull-requests-focal/database/spatialite/label/focal-pr/python/python3.10/django/db/models/query.py"", line 1845, in _insert
    return query.get_compiler(using=using).execute_sql(returning_fields)
  File ""/home/jenkins/workspace/pull-requests-focal/database/spatialite/label/focal-pr/python/python3.10/django/db/models/sql/compiler.py"", line 1853, in execute_sql
    rows = list(self.apply_converters(rows, converters))
  File ""/home/jenkins/workspace/pull-requests-focal/database/spatialite/label/focal-pr/python/python3.10/django/db/models/sql/compiler.py"", line 1500, in apply_converters
    value = row[pos]
IndexError: list index out of range
}}}
This is a long standing issue, however it caused a crash of `GeneratedField` for all output fields that have backend-specific converters when `RETURNING` clause is not supported (MySQL and SQLite < 3.35). We should exacerbate severity to a release blocker.

Regression in d9de74141e8a920940f1b91ed0a3ccb835b55729."	Bug	closed	Database layer (models, ORM)	5.0	Release blocker	fixed		Adam Johnson	Accepted	1	0	0	0	0	0