cmd/go: the -o option does not append .exe suffix to the compiled executable

[shanoaice]

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

$ go version
go version go1.20.3 windows/amd64

Does this issue reproduce with the latest release?

Yes

What operating system and processor architecture are you using (go env)?

go env Output

$ go env
set GO111MODULE=on
set GOARCH=amd64
set GOBIN=
set GOCACHE=C:\Users\Haoqing Chen\AppData\Local\go-build
set GOENV=C:\Users\Haoqing Chen\AppData\Roaming\go\env
set GOEXE=.exe
set GOEXPERIMENT=
set GOFLAGS=
set GOHOSTARCH=amd64
set GOHOSTOS=windows
set GOINSECURE=
set GOMODCACHE=C:\Users\Haoqing Chen\go\pkg\mod
set GONOPROXY=
set GONOSUMDB=
set GOOS=windows
set GOPATH=C:\Users\Haoqing Chen\go
set GOPRIVATE=
set GOPROXY=https://goproxy.cn,direct
set GOROOT=C:\Users\Haoqing Chen\scoop\apps\go\current
set GOSUMDB=sum.golang.org
set GOTMPDIR=
set GOTOOLDIR=C:\Users\Haoqing Chen\scoop\apps\go\current\pkg\tool\windows_amd64
set GOVCS=
set GOVERSION=go1.20.3
set GCCGO=gccgo
set GOAMD64=v3
set AR=ar
set CC=clang
set CXX=clang++
set CGO_ENABLED=0
set GOMOD=D:\projects\sing-box\go.mod
set GOWORK=
set CGO_CFLAGS=-g -O3 -march=native -flto=thin
set CGO_CPPFLAGS=
set CGO_CXXFLAGS=-g -O3 -march=native -flto=thin
set CGO_FFLAGS=-O2 -g
set CGO_LDFLAGS=-g -O3 -march=native -flto=thin
set PKG_CONFIG=pkg-config
set GOGCCFLAGS=-m64 -fno-caret-diagnostics -Qunused-arguments -Wl,--no-gc-sections -fmessage-length=0 -fdebug-prefix-map=C:\Users\HAOQIN~1\AppData\Local\Temp\go-build2509538014=/tmp/go-build -gno-record-gcc-switches

What did you do?

Tried to compile any go program and specify an executable name by -o option, such as go build -o hello ./hello-world.go

What did you expect to see?

The executable name should be hello.exe. clang and gcc both add the .exe suffix automatically.

What did you see instead?

The executable name is simply hello, which will not be recognized by Windows as an executable file.

[dmitshur]

CC @bcmills, @matloob.

[seankhliao]

This was intentional behaviour #3190 (comment)

[bcmills]

Yes, this looks like it's working as documented. The -o flag names a file, not a basename of the file.

Is there some reason you cannot pass -o hello.exe when compiling on Windows?

[bshephar]

I think automagically appending file suffix in this case would not be ideal. I personally, would prefer to see the -o option output exactly what I provide it without having to account for arbitrary OS specific extension differences in behaviour. I think it's easy enough to just provide -o blah.exe as suggested by bcmills if you're working on Windows.

My two cents anyway.

[shanoaice]

Yes, this looks like it's working as documented. The -o flag names a file, not a basename of the file.

Is there some reason you cannot pass -o hello.exe when compiling on Windows?

Well, I personally feels a bit awkward to write separate Makefile targets for Windows and Unix-like systems that outputs a binary to a specific path. I feel like if clang and gcc does it on Windows, it is odd to not have the same behavior for go. After all, having an executable that does not have an .exe suffix on Windows is pointless.

[seankhliao]

.exe is not the only possible extension on windows for executables, and it is possible to execute binaries without extensions at all.

As before, I don't think we want to be changing this as it will make the command less consistent and possibly break existing users.