Name conflict if tracked model has field named "instance"

[shemigon]

Problem

If a tracked model has a field called instance, creating a instance of the model throws

TypeError: Model.__init__() got multiple values for argument 'instance'

See issue #633

Solution

Removed instance argument from the new model init method and used args[0] instead.

Commandments

• Write PEP8 compliant code.
• Cover it with tests.
• Update CHANGES.rst file to describe the changes, and quote according issue with GH-<issue_number>.
• Pay attention to backward compatibility, or if it breaks it, explain why.
• Update documentation (if relevant).

[livenson]

Hi, are there any plans to get this change into the upstream? We are being hit with it and wondering about prospective.

[shemigon]

@livenson I'm not a maintainer of the repository. I created this PR a while ago and it's been unnoticed ever since.

[Copilot]

Pull request overview

This PR fixes issue #633 where models with a field named "instance" would fail with a TypeError when using FieldTracker or ModelTracker. The fix changes the patched __init__ wrapper to use *args, **kwargs instead of explicitly naming the first parameter instance, avoiding conflicts with model field names.

Key Changes:

• Modified patch_init in model_utils/tracker.py to use positional arguments instead of named parameters
• Added test coverage for models with special field names that could conflict with internal parameter names
• Improved timezone handling in timestamp and timeframe model tests by replacing datetime.today() with django.utils.timezone.now()

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
model_utils/tracker.py	Fixed the patch_init method to avoid naming conflicts by using *args and accessing the instance as args[0]
tests/models.py	Added TrackedModelWithSpecialNamedField test model with an "instance" field to verify the fix
tests/test_models/test_special_name_field_model.py	New test file verifying that models with "instance" fields can be created, updated, and deleted
tests/test_models/test_timestamped_model.py	Replaced datetime.today() with timezone-aware now() for proper timezone handling
tests/test_models/test_timeframed_model.py	Replaced datetime.now() with timezone-aware now() for consistency
AUTHORS.rst	Added contributor Boris Shemigon

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[Copilot]

The test should verify that the tracker functionality works correctly for models with an "instance" field. Consider adding assertions to check tracker methods like tracker.has_changed() and tracker.previous() to ensure the fix doesn't break tracker behavior. For example, after updating t.instance = "56.78", verify that t.tracker.has_changed('instance') returns True and t.tracker.previous('instance') returns the old value.