Support violation_error_code and violation_error_message from UniqueConstraint in UniqueTogetherValidator #9766
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rest_framework/serializers.py
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| """ | ||
| for parent_class in [model] + list(model._meta.parents): | ||
| for unique_together in parent_class._meta.unique_together: | ||
| yield unique_together, model._default_manager, [], None | ||
| yield unique_together, model._default_manager, [], None, None, None |
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This is a breaking change: Callers consuming the iterator will experience ValueError: too many values to unpack (expected 4).
For backwards compatibility, the old iterator structure should be returned, unless the new functionality is requested (such as via a default-False argument).
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Thanks for the review. I agree it was a critical change — I’ve restored the original signature and took a different approach.
What's the use case for that? (Why not use model-level default?) |
…ture Extracted error message logic to a separate method. fix: conditionally include violation_error_code for Django >= 5.0 fix(validators): use custom error message and code from model constraints
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Returning the constraint’s default message would change the output and might break users relying on the validator’s default message—for example, in tests or UI rendering. I consider that the current behaviour should be maintained. |
Added support for retrieving custom violation_error_code (for django 5+) and violation_error_message from Django model-level UniqueConstraint definitions and passing them to UniqueTogetherValidator.
refs #9714 and #9352
The update ensures that:
• If violation_error_message or violation_error_code are explicitly defined on the model constraint, they are forwarded to the corresponding validator.
• If the constraint uses the default message/code, they are not passed, allowing the validator to use its own defaults.
Additionally, tests have been added to cover both scenarios:
• When a custom error message/code is used.
• When defaults are applied.
Note: The current structure of
get_unique_together_constraints()may benefit from refactoring (e.g., returning a named structure for clarity and extensibility). This is outside the scope of this PR, but I may explore it in a future contribution.