is this a bug in "go fmt"?

[Sandeep Kalra]

Original code:

$ cat production.go

//go:build production
// +build production
// +build linux  <<<<<< Notice This Line as my production code is only available on Linux

package main

const (
    isProductionCode = true
    isDebugCode      = false
)

$ go fmt production.go

production.go

$ cat production.go

//go:build production
// +build production

package main

const (
    isProductionCode = true
    isDebugCode      = false
)

Thanks,

Sandeep Kalra

[Sandeep Kalra]

and similar issue with other style of adding tags as well

i.e.

// +build tag1,tag2

// +build tag1 tag2

etc

[Sean Liao]

You'll need to provide more info if you want to report a bug:

```

main » cat main.go        

// +build production
// +build linux

package main

21:13:35 ~/tmp/testrepo0017 0:00:00
main » go fmt .
main.go

21:13:39 ~/tmp/testrepo0017 0:00:00
main » cat main.go
//go:build production && linux
// +build production,linux

package main

```

- sean

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[Andrew Harris]

Is this relevant? https://github.com/golang/go/issues/41184

[Sandeep Kalra]

Hi, I will try to explain:

so, I have to run my code at 3 places : linux, windows and darwin. and On each platform there is a production and debug code.

To make this happen, i am using build tags. 

for e.g. to make build for linux in production, the script will use this:

go build --tags "linux, production"  

This is good on build side of things, but not at the go code side. As soon as I send to build process, we do fmt, lint etc, the "go fmt" removes the 2nd tag and then the symbols in go file is not found. 

Best Regards,

Sandeep

[Sandeep Kalra]

probably yes - the implementation of tools for this feature. 

If you see the accepted proposal there is this example:

https://go.googlesource.com/proposal/+/master/design/draft-gobuild.md

// +build 386 windows,amd64 windows

BTW, I am on go1.19.3.

[Andrew Harris]

I think the result of the proposal explains some rewriting in .go files, at least.

I believe the conventional wisdom/best practices here are:

- Use separate, parallel files to hold platform- (or tag-) specific code, e.g:
    init_darwin.go, init_linux.go, init_windows.go

- Prefer setting environment variables GOOS, GOARCH to passing build tag arguments
   
I think these quick guides are up-to-date:
https://www.digitalocean.com/community/tutorials/building-go-applications-for-different-operating-systems-and-architectures
https://www.digitalocean.com/community/tutorials/customizing-go-binaries-with-build-tags

I hope this helps, I'm not convinced I'm not missing something :)

[Sandeep Kalra]

Thanks, sorted out.

this works!

 //go:build debug || linux_debug || darwin_debug || darwin
 // +build debug linux_debug darwin_debug darwin