#34964: Reversing the order of Q objects in a CheckConstraint generates a
migration
-------------------------------------+-------------------------------------
Reporter: Jacob Walls | Owner: Jacob
Type: | Walls
Cleanup/optimization | Status: assigned
Component: Migrations | Version: dev
Severity: Normal | Resolution:
Keywords: noop | Triage Stage: Accepted
Has patch: 1 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------
Comment (by Simon Charette):
The creation of new migrations could be avoided entirely by performing the
sorting only during `__eq__`
{{{#!diff
diff --git a/django/db/models/constraints.py
b/django/db/models/constraints.py
index 56d547e6b0..e221bebd8b 100644
--- a/django/db/models/constraints.py
+++ b/django/db/models/constraints.py
@@ -152,14 +152,22 @@ def __repr__(self):
)
def __eq__(self, other):
- if isinstance(other, CheckConstraint):
- return (
- self.name == other.name
- and self.check == other.check
- and self.violation_error_code ==
other.violation_error_code
- and self.violation_error_message ==
other.violation_error_message
- )
- return super().__eq__(other)
+ if not isinstance(other, CheckConstraint):
+ return super().__eq__(other)
+ # Relax check equality to equivalence comparisons to allow
+ # re-ordering of components.
+ if isinstance(self.check, Q):
+ if not isinstance(other.check, Q) or not
self.check.equivalent_to(
+ other.check
+ ):
+ return False
+ elif self.check != other.check:
+ return False
+ return (
+ self.name == other.name
+ and self.violation_error_code == other.violation_error_code
+ and self.violation_error_message ==
other.violation_error_message
+ )
def deconstruct(self):
path, args, kwargs = super().deconstruct()
}}}
--
Ticket URL: <https://code.djangoproject.com/ticket/34964#comment:5>
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