x/tools/go/analysis/passes/printf: suggest Printf calls without args to use Print

[pierrre]

Go version

1.23.1

Output of go env in your module/workspace:

no relevant

What did you do?

Run the "printf" pass with go vet or golangci-lint

What did you see happen?

It doesn't detect anything for fmt.Printf("some message").

What did you expect to see?

Maybe it should suggest to rewrite fmt.Printf("some message") => fmt.Print("some message"), because it doesn't use any argument.

[gabyhelp]

Related Issues and Documentation

• go vet incorrectly recognizes format verb in string #38131 (closed)
• x/tools/go/analysis: warn on Printf(fmt) #37935
• cmd/vet: false positive about wrong number of arguments in printf #23564 (closed)
• x/tools/analysis: printf pass should only allow %w in fmt.Errorf #37792 (closed)

_{(Emoji vote if this was helpful or unhelpful; more detailed feedback welcome in this discussion.)}

[hyangah]

If this is about tightening printf check further to flag even when the format string is const and requires no verb, I think this should be in proposals since this will cause churns (with unknown benefit).

See the latest proposal & implementation (for 1.24) to tighten the analysis. #60529

[timothy-king]

This is decent style suggestion to give folks, but vet is not the right home for it.

https://github.com/golang/go/blob/master/src/cmd/vet/README#L11-L14

Vet's checks are about correctness, not style. A vet check must identify real or
potential bugs that could cause incorrect compilation or execution. A check that
only identifies stylistic points or alternative correct approaches to a situation
is not acceptable.

[pierrre]

OK, I understand, thank you 😄

[timothy-king]

I am modestly in favor of making suggestions like this in gopls (just not vet). Not sure if it should live in the printf package or not. @findleyr

[adonovan]

There's nothing wrong with using printf with literal strings that don't contain formatting operators, and I don't think we should nag users of vet (or even gopls) for doing so. (There isn't even a performance justification: though Print is faster than Printf, the difference only matters for long strings, and it is extremely rare to printf long string literals repeatedly.)