Enhance queryset with prefetch for many-to-many fields

[Mte90]

Added prefetching of many-to-many fields in queryset.

[Copilot]

Pull request overview

This PR enhances the queryset optimization in get_queryset() to automatically detect and prefetch many-to-many fields alongside the existing select_related optimization for foreign keys. This prevents N+1 query problems when accessing many-to-many relationships through nested field notation.

Key Changes:

• Added prefetch_fields list to collect ManyToManyField relationships
• Updated field type detection logic to differentiate between ForeignKey/OneToOneField and ManyToManyField
• Applied prefetch_related() to the queryset when many-to-many fields are detected

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[Copilot]

The models module is not imported at the module level. This will cause a NameError when this code executes. Add from django.db import models at the top of the file with the other imports.

[Mte90]

@copilot that's wrong because this is a class extending from another and as you can see it is internal as parameter not from that value

[Copilot]

The new prefetch_related functionality for ManyToManyField relationships lacks test coverage. Consider adding tests that verify:

1. ManyToMany fields are correctly identified and added to prefetch_fields
2. The queryset actually has prefetch_related applied
3. No N+1 query issues occur when accessing many-to-many relationships

You may need to add a ManyToManyField to one of the test models (e.g., in tests/test_app/models.py) to properly test this functionality.

[Copilot]

The call to self.model._meta.get_field(base_field) can raise a FieldDoesNotExist exception if the base_field doesn't exist on the model. Consider wrapping this in a try-except block to handle invalid field names gracefully:

try:
    model_field = self.model._meta.get_field(base_field)
    if isinstance(model_field, (models.ForeignKey, models.OneToOneField)):
        # ...
except FieldDoesNotExist:
    continue  # Skip invalid field names

This pattern is used elsewhere in the codebase (e.g., in turbodrf/mixins.py line 153).

[Mte90]

base_field always exists, @copilot as you can see in the lines above

[AlexanderCollins]

Thanks for this PR! M2M field prefetching has been implemented in v0.2.0 - the get_queryset() method now automatically detects and applies prefetch_related() for many-to-many relationships alongside the existing select_related() optimization for foreign keys.