Fixed #36594 -- Improved UniqueConstraint's nulls_distinct system check warning #19870
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sarahboyce
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Sep 19, 2025
django/db/models/constraints.py
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| f"{connection.display_name} does not support unique constraints " | ||
| "with nulls distinct.", | ||
| "with nulls distinct. They are ignored for databases besides " | ||
| "PostgreSQL 15+.", |
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I would maybe have:
f"{connection.display_name} does not support the "
"'nulls_distinct' parameter for unique constraints.",As I think we want to emphasizing that having values for nulls_distinct set is not supported (rather than this being interpreted that nulls_distinct=False might be valid
Note that any changes to the warning needs to be updated in the system check docs:
--- a/docs/ref/checks.txt
+++ b/docs/ref/checks.txt
@@ -438,8 +438,8 @@ Models
expression and won't be validated during the model ``full_clean()``.
* **models.W046**: ``<database>`` does not support comments on tables
(``db_table_comment``).
-* **models.W047**: ``<database>`` does not support unique constraints with
- nulls distinct.
+* **models.W047**: ``<database>`` does not support the 'nulls_distinct'
+ parameter for unique constraints.
* **models.E048**: ``constraints/indexes/unique_together`` refers to a
``CompositePrimaryKey`` ``<field name>``, but ``CompositePrimaryKey``\s are
not supported for that option.There was a problem hiding this comment.
parameter -> argument
or perhaps "does not support UniqueConstraint.nulls_distinct."
…ck warning. Clarified unique constraints with nulls distinct are ignored for databases besides PostgreSQL 15+. Added warning in unique constraint docs. Thanks Russell Owen for the report.
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I have just pushed out a patch with the improvements. Apologies for the delay. |
Samriddha9619
approved these changes
Oct 6, 2025
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Clarified unique constraints with nulls distinct are ignored for databases besides PostgreSQL 15+. Added warning in unique constraint docs.
Thanks Russell Owen for the report.
Trac ticket number
ticket-36594
Branch description
Expanded error message for
UniqueConstraint'snulls_distinctcheck to clarify thatnulls_distinctare ignored for databases besides PostgreSQL 15+. Additionally, converted relevant docs note to warning to make it more obvious.Checklist
mainbranch.