FieldError: Unsupported lookup error message can be confusing.

[Alex]

On these example queries on DateTimeFields:

TestModel.objects.filter(created_at__gt__foo='2024-01-01')
TestModel.objects.filter(created_at__gt__='2024-01-01')  # I'm a bit surprised this one also has the same message.
TestModel.objects.filter(created_at__gt__lt='2024-01-01')

The error message is this

django.core.exceptions.FieldError: Unsupported lookup 'gt' for DateTimeField or join on the field not permitted, perhaps you meant gt or gte?

The error message should clarify better the issue.

[Sarah Boyce]

Replicated, this is also true of other fields.
I agree that saying something like Unsupported lookup 'gt__foo', Unsupported lookup 'gt__', and Unsupported lookup 'gt__lt' would be clearer.

[Amir Karimi]

Replying to Sarah Boyce:

Replicated, this is also true of other fields.
I agree that saying something like Unsupported lookup 'gt__foo', Unsupported lookup 'gt__', and Unsupported lookup 'gt__lt' would be clearer.

If we just pass down LOOKUP_SEP.join(arg.split(LOOKUP_SEP)[1:]) to the build_lookup method, it can print out the input lookup entirely.
It outputs'gt__foo', 'gt__' , and 'gt__lt' .
It can be an argument to the try_transform method. Not sure wether name is needed or not. Thoughts?

[wookkl]

Can I resolve this issue?

[wookkl]

PR ​https://github.com/django/django/pull/18293

[Sarah Boyce <42296566+sarahboyce@…>]

In 759abc4d:

Fixed #35413 -- Made unsupported lookup error message more specific.