Add 'Did you mean' suggestions for unsupported lookup error

[Rich Jones]

I often find myself running into django.core.exceptions.FieldError: Unsupported lookup 'is_null' for DateTimeField or join on the field not permitted. - and it seems like plenty of other people on StackOverflow do as well.

It'd be great if we hit an unsupported lookup, we could suggest the correct one if if it's similar, so it'd become:

django.core.exceptions.FieldError: Unsupported lookup 'is_null' for DateTimeField or join on the field not permitted - did you mean isnull?

Thanks!

[Tim Graham]

It seems worth exploring. difflib from the standard library seems promising for the example you gave:

>>> import difflib
>>> difflib.get_close_matches('is_null', ['isnull'])
['isnull']

[Abhinav Patil]

Is the purpose of this ticket to add "did you mean" suggestions for "django.core.exceptions.FieldError" only, or for any similar error?

[Abhinav Patil]

Assuming the ticket refers only to errors of the form django.core.exceptions.FieldError: Unsupported lookup '<INCORRECT_FIELD>' for <SOME_MODEL> or join on the field not permitted., I believe I can add this feature, so I am assigning the ticket to myself.

[Abhinav Patil]

I've submitted a pull request here: ​https://github.com/django/django/pull/10457

[Abhinav Patil]

This is my first patch, so forgive me for what is probably a silly question, and I couldn't find anything concrete answering my question in the docs... anyways, the question: what happens now? Is there a process for getting this patch reviewed or is it along the lines of "just wait and someone will do it eventually"?

[Tim Graham <timograham@…>]

In bf01994a:

Fixed #29804 -- Added 'did you mean' suggestions for unsupported lookup error.