cmd/go: go list reports a confusing StaleReason

[perillo]

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

$ go version
go version go1.13.6 linux/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
GO111MODULE="on"
GOARCH="amd64"
GOBIN="/home/manlio/.local/bin"
GOCACHE="/home/manlio/.cache/go-build"
GOENV="/home/manlio/.config/go/env"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GONOPROXY="github.com/perillo"
GONOSUMDB="github.com/perillo"
GOOS="linux"
GOPATH="/home/manlio/.local/lib/go:/home/manlio/src/go"
GOPRIVATE="github.com/perillo"
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/usr/lib/go"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/lib/go/pkg/tool/linux_amd64"
GCCGO="gccgo"
AR="ar"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD="/tmp/mod/go.mod"
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-build719321233=/tmp/go-build -gno-record-gcc-switches"
GOROOT/bin/go version: go version go1.13.6 linux/amd64
GOROOT/bin/go tool compile -V: compile version go1.13.6
uname -sr: Linux 5.4.13-arch1-1
/usr/lib/libc.so.6: GNU C Library (GNU libc) stable release version 2.30.
gdb --version: GNU gdb (GDB) 8.3.1

What did you do?

From outside of a Go module (e.g. in the \tmp directory), and GO111MODULE=on

go clean -modcache -cache
go install golang.org/x/tools/go/packages
go list -f '{{ .StaleReason }}' golang.org/x/tools/go/packages

What did you expect to see?

An empty StaleReason

What did you see instead?

not installed but available in build cache

This seems confusing, since the documentation of Stale is would 'go install' do anything for this package?. However go install will do nothing for this package, excluding making it available in the build cache and module cache.

Without first go install, I get

stale dependency: golang.org/x/tools/go/internal/gcimporter

[bcmills]

This is fixed in go1.14beta1 via #32027.

$ export GO111MODULE=on

$ go1.14beta1 install golang.org/x/tools/go/packages
can't load package: cannot find module providing package golang.org/x/tools/go/packages: working directory is not part of a module

$ go1.14beta1 list -f '{{ .StaleReason }}' golang.org/x/tools/go/packages
can't load package: cannot find module providing package golang.org/x/tools/go/packages: working directory is not part of a module