golang.org/dl/gotip: command should override GOROOT with its tip packages location

[lggomez]

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

$ go version
1.13.4

Does this issue reproduce with the latest release?

Yes

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

go env

$ go env
GO111MODULE=""
GOARCH="amd64"
GOBIN=""
GOCACHE="/root/.cache/go-build"
GOENV="/root/.config/go/env"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GONOPROXY=""
GONOSUMDB=""
GOOS="linux"
GOPATH="/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/usr/local/go"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/local/go/pkg/tool/linux_amd64"
GCCGO="gccgo"
AR="ar"
CC="gcc"
CXX="g++"
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 -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build255297653=/tmp/go-build -gno-record-gcc-switches"

What did you do?

While verifying an issue fix from tip (#34123), I built the affected repro case I have using gotip run main.go

What did you expect to see?

I expected the compiled app to use the runtime packages downloaded by it

What did you see instead?

The app was still being built using the local GOROOT packages. I had to override GOROOT manually to achieve that end: GOROOT=~/sdk/gotip gotip run main.go

Since the purpose of gotip is to serve as a downloader and nightly version of Go it could be more consistent from an usability standpoint for it to use its packages by default (although I guess that this would be a breaking change because all users of this all are already used to this behavior)

[ianlancetaylor]

Do you normally have GOROOT set in the environment? You shouldn't.

[lggomez]

Yes but because I use this version of gvm to manage multiple go versions at work

In this specific case it was a docker container, I would have to check if it is set up by default on our production images but I don´t recall tweaking it on this specific container

[dmitshur]

Which version of gotip are you using? Is it the latest?

I believe this exact change was very recently implemented via CL 206537 and issue #35507. Please let me know if I'm overlooking something.

[lggomez]

@dmitshur it wasn´t the latest, updating it solved it. Thanks