Attach Diagnostic to "function x does not exist" error

[eliaperantoni]

Is your feature request related to a problem or challenge?

For a query like:

SELECT idontexist(1)'

The only message that the end user of an application built atop of DataFusion sees is:

Error during planning: Invalid function 'idontexist'.
Did you mean 'datepart'?

We want to provide a richer message that references and highlights locations in the original SQL query, and contextualises and helps the user understand the error. In the end, it would be possible to display errors in a fashion akin to what was enabled by #13664 for some errors:

See #14429 for more information.

Describe the solution you'd like

Attach a well crafted Diagnostic to the DataFusionError, building on top of the foundations laid in #13664. See #14429 for more information.

Describe alternatives you've considered

No response

Additional context

No response

[onlyjackfrost]

take

[alamb]

I think this is a good first issue as the need is clear and the tests in https://github.com/apache/datafusion/blob/85fbde2661bdb462fc498dc18f055c44f229604c/datafusion/sql/tests/cases/diagnostic.rs are well structured for extension.

Thanks @onlyjackfrost

[eliaperantoni]

Hey @onlyjackfrost how is it going with this ticket :) Can I help with anything?

[onlyjackfrost]

Hi @eliaperantoni sorry for the late reply.
I'm working on this and aim to raise a PR over the weekend.
I'll let you know if I have any questions. Thanks for being so friendly! :)

[onlyjackfrost]

Hi @eliaperantoni, just updating my progress.
I've implemented the diagnostic like this. I'm not sure my implementation is in the right direction.
@eliaperantoni thanks for implementing the try_from_sqlparser_span in the first place, I was struggling with how to get the span from the function.

.map_err(|e| {
    let span = Span::try_from_sqlparser_span(sql_parser_span);
    let mut diagnostic =
        Diagnostic::new_error(format!("Invalid function '{name}'"), span);
    diagnostic.add_note(
        format!("possible function {}", suggested_func_name),
        None,
    );
    e.with_diagnostic(diagnostic)
})

I'm trying to add test case in the /sql/cases/diagnostic.rs file... will raise PR later.

[eliaperantoni]

@onlyjackfrost yes that's perfect!

I'm trying to add test case in the /sql/cases/diagnostic.rs file... will raise PR later.

Sweet! Looking forward to it. Great job :)

[onlyjackfrost]

@eliaperantoni I just raised my PR, could you help review it?
Thanks =D