tracing

What it does

Detects and fixes overly complex statements for tracing lib

Specifically for recording fields

Lint Name

simplify_tracing_field_record

Category

complexity

Advantage

• Removes unnecessary complexity

Drawbacks

• possibly tough to detect? maybe?
• possibly increases complexity for expressions like info_span!("foo", a = format!("{:?}", bar.baz.quux()))

Example

// both ...
info_span!("foo", a = format!("{:?}", bar))
// and
info_span!("foo", a = format!("{bar:?}"))

Could be written as:

info_span!("foo", a = ?bar)

and

info_span!("foo", a = format!("{}", bar))
// or 
info_span!("foo", a = format!("{bar}"))

Could be written as:

info_span!("foo", a = %bar)

(same for debug_span!, warn_span!, error_span, ...)

1. See macros: https://docs.rs/tracing/latest/tracing/index.html#macros
2. See ? and % described https://docs.rs/tracing/latest/tracing/index.html#recording-fields

Start with the tracing macro and recording-fields documentation linked in the issue, then review the examples for ? and % field recording. Done means the simplify_tracing_field_record lint handles the shown info_span! forms and corresponding span macros while considering the stated concern about complex expressions.