go/printer: output differs to "go fmt" for consts and structs #69843
Description
Go version
go version go1.23.2 linux/amd64
Output of go env in your module/workspace:
GO111MODULE=''
GOARCH='amd64'
GOBIN=''
GOCACHE='/home/szi/.cache/go-build'
GOENV='/home/szi/.config/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFLAGS=''
GOHOSTARCH='amd64'
GOHOSTOS='linux'
GOINSECURE=''
GOMODCACHE='/home/szi/go/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='linux'
GOPATH='/home/szi/go'
GOPRIVATE=''
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/opt/go1.23.2.linux-amd64'
GOSUMDB='sum.golang.org'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/opt/go1.23.2.linux-amd64/pkg/tool/linux_amd64'
GOVCS=''
GOVERSION='go1.23.2'
GODEBUG=''
GOTELEMETRY='local'
GOTELEMETRYDIR='/home/szi/.config/go/telemetry'
GCCGO='gccgo'
GOAMD64='v1'
AR='ar'
CC='gcc'
CXX='g++'
CGO_ENABLED='1'
GOMOD='/dev/null'
GOWORK=''
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
PKG_CONFIG='pkg-config'
GOGCCFLAGS='-fPIC -m64 -pthread -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=/tmp/go-build736226514=/tmp/go-build -gno-record-gcc-switches'What did you do?
Source
package main
import (
"fmt"
"go/parser"
"go/printer"
"go/token"
"log"
"os"
"os/exec"
"path/filepath"
"runtime"
)
const (
FirstConst = iota
SecondConst
)
type FirstStruct struct {
FirstProperty string
SecondProperty string
}
func main() {
// Get source filename
var err error
_, InputName, _, ok := runtime.Caller(0)
if !ok {
log.Fatalf("Can not read source.")
}
// Parse source file
Fileset := token.NewFileSet()
Source, err := parser.ParseFile(Fileset, InputName, nil, parser.ParseComments)
if err != nil {
log.Fatal(err)
}
// Write source
OutputName := fmt.Sprintf("printer-%s", filepath.Base(InputName))
Output, err := os.Create(OutputName)
if err != nil {
log.Fatal(err)
}
err = printer.Fprint(Output, Fileset, Source)
if err != nil {
log.Fatal(err)
}
Output.Close()
// Compare
cmp := exec.Command("cmp", InputName, OutputName)
err = cmp.Run()
if err != nil {
log.Fatal(err)
}
}
What did you see happen?
$ go fmt inconsistency.go
$ go run inconsistency.go
2024/10/11 09:58:41 exit status 1
exit status 1
$ diff inconsistency.go printer-inconsistency.go
16c16
< FirstConst = iota
---
> FirstConst = iota
21,22c21,22
< FirstProperty string
< SecondProperty string
---
> FirstProperty string
> SecondProperty string
The command go fmt and the package go/print do something different for consts and structs.
What did you expect to see?
No difference