cmd/link: -X doesn't work for vendored packages

[iterion]

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

go version go1.7.3 linux/amd64

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

GOARCH="amd64"
GOBIN=""
GOEXE=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOOS="linux"
GOPATH="/home/iterion/dev/go"
GORACE=""
GOROOT="/usr/lib/go"
GOTOOLDIR="/usr/lib/go/pkg/tool/linux_amd64"
CC="gcc"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build201245685=/tmp/go-build -gno-record-gcc-switches"
CXX="g++"
CGO_ENABLED="0"

What did you do?

Run this build command with github.com/iterion/remotepkg in the vendor directory:
note: package above doesn't actually exist yet, but I can create it if needed for demonstration purposes.

go build -a -installsuffix cgo -o test -ldflags "-X github.com/iterion/remotepkg.timestamp=`date -u '+%Y-%m-%d_%I:%M:%S%p'`" .

main.go

package main

import (
  "github.com/iterion/remotepkg"
)

func main() {
  remotepkg.PrintEnv()
}

remotepkg.go

package remotepkg

import (
  "log"
)

var timestamp string

func PrintEnv() {
  log.Println(timestamp)
}

What did you expect to see?

Expect ./test to print build time.

What did you see instead?

Nothing is printed.

If the remote package is not in the vendor dir but does exist in your gopath in an expected place then the build time is correctly printed.

[davecheney]

The name of the package, as seen by the linker when applying the -X flagis the full path name realtive to GOPATH

…

On Thu, 9 Feb 2017, 10:32 Adam Sunderland ***@***.***> wrote: What version of Go are you using (go version)? go version go1.7.3 linux/amd64 What operating system and processor architecture are you using (go env)? GOARCH="amd64" GOBIN="" GOEXE="" GOHOSTARCH="amd64" GOHOSTOS="linux" GOOS="linux" GOPATH="/home/iterion/dev/go" GORACE="" GOROOT="/usr/lib/go" GOTOOLDIR="/usr/lib/go/pkg/tool/linux_amd64" CC="gcc" GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build201245685=/tmp/go-build -gno-record-gcc-switches" CXX="g++" CGO_ENABLED="0" What did you do? Run this build command with github.com/iterion/remotepkg in the vendor directory: note: package above doesn't actually exist yet, but I can create it if needed for demonstration purposes. go build -a -installsuffix cgo -o test -ldflags "-X github.com/iterion/remotepkg.timestamp=`date <https://github.com/iterion/remotepkg.timestamp=date> -u '+%Y-%m-%d_%I:%M:%S%p'`" . main.go package main import ( "github.com/iterion/remotepkg" ) func main() { remotepkg.PrintEnv() } remotepkg.go package remotepkg import ( "log" ) var timestamp string func PrintEnv() { log.Println(timestamp) } What did you expect to see? Expect ./test to print current time. What did you see instead? Nothing is printed. If the remote package is not in the vendor dir but does exist in your gopath in an expected place then the current time is correctly printed. — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#19000>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAAcA_mvXooFWVIGkbM9QJbEfiI4rKxUks5ralB2gaJpZM4L7gjB> .

[iterion]

@davecheney thanks
I tested this, given main.go is in github.com/iterion/test I changed change it to

"-X  github.com/iterion/test/vendor/github.com/iterion/remotepkg.timestamp=time"

which correctly prints time.

Is there documentation for this anywhere (I struggled to find any aside from stackoverflow)? I'd be up for trying to update it.

Closing this in the meantime as it seems there is no actual issue.

[davecheney]

Not that I know of I'm afraid, this is a side effect of the language way vendoring is implemented

…

On Thu, 9 Feb 2017, 10:57 Adam Sunderland ***@***.***> wrote: @davecheney <https://github.com/davecheney> thanks I tested this, given main.go is in github.com/iterion/test I changed change it to "-X github.com/iterion/test/vendor/github.com/iterion/remotepkg.timestamp=time" which correctly prints time. Is there documentation for this anywhere (I struggled to find any aside from stackoverflow)? I'd be up for trying to update it. Closing this in the meantime as it seems there is no actual issue. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#19000 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAAcA-LtUqhJYta0AYFb3YgkR8B25kFCks5ralZ9gaJpZM4L7gjB> .

[minux]

Ian updated the docs to suggest 'go tool nm' to find the correct symbol name, but due to various corner cases, that docs change is rolled back. In practice, though, you can still use the 'go tool nm' command to figure out the correct symbol name. Please see https://golang.org/cl/34791 for the corner cases and the (reverted) docs on how to use "go tool nm".