cmd/link: unable to set LDFLAGS -X for a vendored variable

[vearutop]

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

$ go version
go version go1.11 darwin/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
GOARCH="amd64"
GOBIN=""
GOCACHE="/Users/viacheslav.poturaev/Library/Caches/go-build"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GOOS="darwin"
GOPATH="/Users/viacheslav.poturaev/go"
GOPROXY=""
GORACE=""
GOROOT="/usr/local/Cellar/go/1.11/libexec"
GOTMPDIR=""
GOTOOLDIR="/usr/local/Cellar/go/1.11/libexec/pkg/tool/darwin_amd64"
GCCGO="gccgo"
CC="clang"
CXX="clang++"
CGO_ENABLED="1"
GOMOD=""
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/var/folders/lb/j0gz8jln36z4frqkrzmkdb0c0000gp/T/go-build187400651=/tmp/go-build -gno-record-gcc-switches -fno-common"

What did you do?

Tried to set a value to a variable in vendored package by import path.

go run -ldflags "-X github.com/some/lib/pkg/version.Version=1.2.3" main.go

Or

go run -ldflags "-X vendor/github.com/some/lib/pkg/version.Version=1.2.3" main.go

What did you expect to see?

A value of "1.2.3" being assigned to github.com/some/lib/pkg/version.Version.

What did you see instead?

Default value is kept.

The value can be only set with full $GOPATH import path:

go run -ldflags "-X github.com/my/project/vendor/github.com/some/lib/pkg/version.Version=1.2.3" main.go

[ianlancetaylor]

Closing as dup of #25011.