Two different bugs related to model inheritance:
1.
Consider the following models:
class A(models.Model):
field1 = models.IntegerField()
class B(A):
field2 = models.IntegerField()
class C(models.Model):
b = models.ForeignKey(B, on_delete=models.CASCADE)
queryset = C.objects.select_related('b').select_for_update(of=('b'))
The above queryet generates the following query:
SELECT "selectforupdate_c"."id",
"selectforupdate_c"."b_id",
"selectforupdate_a"."id",
"selectforupdate_a"."field1",
"selectforupdate_b"."a_ptr_id",
"selectforupdate_b"."field2"
FROM "selectforupdate_c"
INNER JOIN "selectforupdate_b"
ON ( "selectforupdate_c"."b_id" =
"selectforupdate_b"."a_ptr_id" )
INNER JOIN "selectforupdate_a"
ON ( "selectforupdate_b"."a_ptr_id" = "selectforupdate_a"."id" )
FOR UPDATE OF "selectforupdate_a"
The of clause in the generated SQL references the model a instead of b
2.
Consider the following models:
class A(models.Model):
field1 = models.IntegerField()
class B(A):
field2 = models.IntegerField()
class C(B):
field_c = models.IntegerField()
queryset = C.objects.all().select_for_update(of=('b_ptr', 'b_ptr__a_ptr'))
The above queryset crashes with the following crashlog:
Traceback (most recent call last):
File "/home/abhijeet/git-repos/django/django/core/management/base.py", line 328, in run_from_argv
self.execute(*args, **cmd_options)
File "/home/abhijeet/git-repos/django/django/core/management/base.py", line 369, in execute
output = self.handle(*args, **options)
File "/home/abhijeet/django_contrib/selectforupdate/management/commands/debug.py", line 12, in handle
print(queryset.query)
File "/home/abhijeet/git-repos/django/django/db/models/sql/query.py", line 257, in __str__
sql, params = self.sql_with_params()
File "/home/abhijeet/git-repos/django/django/db/models/sql/query.py", line 265, in sql_with_params
return self.get_compiler(DEFAULT_DB_ALIAS).as_sql()
File "/home/abhijeet/git-repos/django/django/db/models/sql/compiler.py", line 555, in as_sql
of=self.get_select_for_update_of_arguments(),
File "/home/abhijeet/git-repos/django/django/db/models/sql/compiler.py", line 1036, in get_select_for_update_of_arguments
select_index = klass_info['select_fields'][0]
IndexError: list index out of range
This is related to #30953
I forgot to link to my PR:
PR