go fmt: kept whitespace around *

What version of Go are you using (go version)?

$ go version
go version go1.16.14 linux/amd64

Does this issue reproduce with the latest release?

Not sure.

What did you do?

go fmted on

package main

import "fmt"

func main() {
	a, b, c := 3, 4, 5

	if (a*a)+(b*b) == (c * c) {
		fmt.Println("it is!")
	}
}

https://go.dev/play/p/BhOt_NMASo9

What did you expect to see?

Space around * in (c * c) to be removed

What did you see instead?

They aren't

[ianlancetaylor]

Thanks, but this whitespace formatting is working as intended. It's meant to make expressions more readable. See also #1206 and #35229.

Thanks, but this whitespace formatting is working as intended. It's meant to make expressions more readable.

How? Spaces around the first two * were removed.

Running go fmt on (https://go.dev/play/p/DzTsgisxj66)

package main

import "fmt"

func main() {
	a, b, c := 3, 4, 5

	if (a  * a)+(b  *     b) == (c * c) {
		fmt.Println("it is!")
	}
}

or on (https://go.dev/play/p/eUaLixFMpeN)

package main

import "fmt"

func main() {
	a, b, c := 3, 4, 5

	if (a*a)+(b*b) == (c*c) {
		fmt.Println("it is!")
	}
}

produces the same result

[ianlancetaylor]

Yes. The whitespace in subexpressions is removed so that it doesn't obscure the fact that it is in a subexpression.

These formatting decisions date back more than a decade. For better or for worse, we aren't going to change them now. The issue tracker is not the place to discuss them. Please see https://go.dev/wiki/Questions.

For better or for worse, we aren't going to change them now.

Why?

The issue tracker is not the place to discuss them

How can this is not the place to discuss them?

[ianlancetaylor]

For better or for worse, we aren't going to change them now.

Why?

Because many people use version control systems that enforce that all submitted code be formatted according to gofmt. That means that changes to gofmt cause considerable churn for those organizations, causing operations like git blame to become less useful due to formatting churn. Therefore, at this stage in the development of Go, we only change gofmt for dramatic readability improvements, not for minor ones.

The issue tracker is not the place to discuss them

How can this is not the place to discuss them?

As I said before, please see https://go.dev/wiki/Questions. Thanks.

Because many people use version control systems that enforce that all submitted code be formatted according to gofmt. That means that changes to gofmt cause considerable churn for those organizations, causing operations like git blame to become less useful due to formatting churn. Therefore, at this stage in the development of Go, we only change gofmt for dramatic readability improvements, not for minor ones.

As for I know, git blame has ways to prevent that from happening.

@rsc and @griesemer, what's your opinion on this?

[griesemer]

@frogtile I believe @ianlancetaylor has answered this already for all of us. To repeat: changing this would cause likely millions of lines of code to be reformatted for no particularly strong reason.

I understand that you'd like a different formatting convention and you're free to make that happen for yourself: the code is in go/printer/nodes.go, search for binaryExpr.

Please move any further discussions elsewhere, thanks. This issue is closed.