chore: correctly validate unique constraints with distinct condition fields #9744
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…ogether validator
| for unique_together in parent_class._meta.unique_together: | ||
| yield unique_together, model._default_manager, [], None | ||
| for constraint in parent_class._meta.constraints: | ||
| if isinstance(constraint, models.UniqueConstraint) and len(constraint.fields) > 1: |
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do this need to be removed?
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We're now including the condition fields as part of the applicable fields that contribute to this count below. If we kept this here the condition fields would not be considered, which we need for this fix.
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Shouldn't there be a distinction made between condition fields and constraint fields here?
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We could split out the logic for clarity to require >1 constraint fields or 1 constraint field and 1+ condition fields distinct from the constraint field. Practically that would be the same however.
If you want to split our unique together constraints with a single constraint field and distinct condition fields into a new method, that would require a larger refactor of the existing constraint validation code.
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Pull Request Overview
This PR updates DRF’s validation to correctly treat single-field UniqueConstraint entries with additional condition fields as unique-together validations rather than per-field UniqueValidators.
- Extend unique-together detection to include UniqueConstraint with one field when the condition references other fields.
- Adjust field-level UniqueValidator generation to only apply when no additional condition fields are referenced.
- Add tests covering condition-based unique-together behavior.
Reviewed Changes
Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.
| File | Description |
|---|---|
| tests/test_validators.py | Adds a model, serializer, and tests for condition-based unique-together validation; updates expectations for single-field UniqueConstraint behavior. |
| rest_framework/utils/field_mapping.py | Imports helper and changes logic to only create UniqueValidator when the union of fields and condition fields is a single field. |
| rest_framework/serializers.py | Updates unique-together constraint discovery to include single-field UniqueConstraints when conditions reference additional fields. |
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| ConditionUniquenessTogetherModel.objects.create(race_name='example', position=1) | ||
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| data = {'race_name': 'example', 'position': 0} | ||
| serializer = ConditionUniquenessTogetherSerializer(self.instance, data=data) |
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The serializer under test is passed an instance of UniquenessTogetherModel (self.instance) instead of ConditionUniquenessTogetherModel. This will cause the update validation to target the wrong model. Capture and pass the instance of ConditionUniquenessTogetherModel created in this test.
| ConditionUniquenessTogetherModel.objects.create(race_name='example', position=1) | |
| data = {'race_name': 'example', 'position': 0} | |
| serializer = ConditionUniquenessTogetherSerializer(self.instance, data=data) | |
| instance = ConditionUniquenessTogetherModel.objects.create(race_name='example', position=1) | |
| data = {'race_name': 'example', 'position': 0} | |
| serializer = ConditionUniquenessTogetherSerializer(instance, data=data) |
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| Failing unique together validation should result in non field errors when a condition-based | ||
| unique together constraint is violated. |
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Hyphenate 'non-field errors' for correctness and consistency with DRF terminology.
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3 participants
Description
Resolves: #9707.