#31246 closed Bug (fixed)
select_for_update() with "of" uses wrong tables from (multi-level) model inheritance.
Description (last modified by ) ¶
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
Change History (11)
comment:1 by , 5 years ago
Description: | modified (diff) |
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comment:2 by , 5 years ago
Keywords: | select_for_update; mti; relations; → select_for_update mti relations |
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Severity: | Normal → Release blocker |
Triage Stage: | Unreviewed → Accepted |
comment:3 by , 5 years ago
Version: | master → 2.2 |
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comment:4 by , 5 years ago
Has patch: | set |
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comment:5 by , 5 years ago
Needs tests: | set |
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Patch needs improvement: | set |
Summary: | Related Model with inheritance generates wrong select_for_update 'of' → select_for_update() with "of" uses wrong tables from (multi-level) model inheritance. |
It is a data loss issue introduced in 0107e3d1058f653f66032f7fd3a0bd61e96bf782 (Django 2.2.8).
comment:6 by , 5 years ago
Description: | modified (diff) |
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comment:7 by , 5 years ago
Description: | modified (diff) |
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comment:8 by , 5 years ago
Needs tests: | unset |
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Patch needs improvement: | unset |
Triage Stage: | Accepted → Ready for checkin |
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