fix[ux]: fix empty hints in error messages

[sandbubbles]

What I did

Remove empty hint message from exceptions. As in #4313.

How I did it

Modify the check of absent hint to include an empty string.

How to verify it

Commit message

remove empty hint message from exceptions. this regression was
introduced in 03095ce3921636. the root cause of the issue, however,
was that `hint=""` could be constructed in the first place. this commit
fixes the `get_levenshtein_error_suggestions` helper so that it returns
`None` on failure to find a suggestion rather than the empty string
`""`.

Description for the changelog

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[sandbubbles]

UndeclaredException is the only place where I encountered empty hints. An alternative solution is to add the check there to prevent the hint from being an empty string in the first place.

[charles-cooper]

It seems like a code smell that we are creating empty string hints in the first place. Do we know where they are coming from?

[sandbubbles]

It seems like a code smell that we are creating empty string hints in the first place. Do we know where they are coming from?

I think its as in this - #4351 (comment) - just the UndeclaredException. But I can spend some more time if i encounter it elsewhere.

[charles-cooper]

note the regression comes from #4154 -- the previous code checked for truthy value of self.hint.

[sandbubbles]

note the regression comes from #4154 -- the previous code checked for truthy value of self.hint.

Yeah, I think there are two main solutions:

1. Have the check in the same way as pre fix[ux]: fix empty hints in error messages #4351 - (which is proposed in this PR, because i though hint can be only None or string, but I can rewrite it to if not hint to keep the truthyness).
2. Or keep the current test if hint is None and modify get_levenshtein_error_suggestions to return None instead of an empty string (which is used as the hint in one type of UndeclaredDefinition)

I think the second solution is cleaner, but the first solution ensures that we catch any missed empty string hints.
What do you prefer?

[charles-cooper]

i think 2. is better -- we should not be supplying empty string as a hint!

[sandbubbles]

i think 2. is better -- we should not be supplying empty string as a hint!

Hope its better now :)