cmd/go: cannot load <package>, disallowed version string ""

[zikaeroh]

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

$ go version
go version devel +06e34e5 Sat Jun 15 14:23:04 2019 +0000 linux/amd64

Does this issue reproduce with the latest release?

Not in 1.12.5, yes on tip.

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

go env Output

$ go env
GO111MODULE=""
GOARCH="amd64"
GOBIN=""
GOCACHE="/home/jake/nobackup/gotip_home/cache/go-build"
GOENV="/home/jake/nobackup/gotip_home/config/go/env"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GONOPROXY=""
GONOSUMDB=""
GOOS="linux"
GOPATH="/home/jake/nobackup/gotip_home/gopath"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/home/jake/sdk/gotip"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/home/jake/sdk/gotip/pkg/tool/linux_amd64"
GCCGO="gccgo"
AR="ar"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD="/home/jake/decbug/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-build227879872=/tmp/go-build -gno-record-gcc-switches"

What did you do?

go.mod:

module decbug

go 1.12

main.go:

package main

import _ "github.com/ericlagergren/decimal"

func main() {}

Run go build.

What did you expect to see?

No errors on building, dependencies populated, etc.

What did you see instead?

go build fails with:

go: finding github.com/ericlagergren/decimal latest
go: finding github.com/ericlagergren/decimal 
build decbug: cannot load github.com/ericlagergren/decimal: disallowed version string ""

Running go mod tidy always outputs:

go: finding github.com/ericlagergren/decimal latest
go: finding github.com/ericlagergren/decimal 

go build in 1.12.5 works fine, along with mod tidy, etc.

[Azareal]

go get github.com/mailru/easyjson/...: disallowed version string ""
The same thing seems to happen with go get -u github.com/mailru/easyjson/...

Is this deliberate or an accidental break?

[zikaeroh]

Bisects to CL 180337 (4c2ffd2).

[mvdan]

I have been encountering the same error in the last couple of days on master. I didn't file an issue because I thought I was doing something silly. Using 1.12.6 let me work around the issue when adding new dependencies.

This probably needs more investigation, but for now I'm adding it as a 1.13 release blocker. CC @jayconrod @bcmills

[eliasnaur]

FWIW, I had a similar same error message and setting GOPROXY=direct fixed the problem. I didn't investigate why.

[jayconrod]

Reproduced. Will look into this today.

[cuonglm]

@jayconrod The problem is the empty "" current param passed to queryProxy, which causes module.EncodeVersion return error.

[gopherbot]

Change https://golang.org/cl/182697 mentions this issue: cmd/go/internal/modload: query correct "latest" version through proxy

[zikaeroh]

The above CL seems to fix the issue in my projects. Thanks!

[jayconrod]

@zikaeroh Thanks for verifying, and thanks for reporting the issue. The fix is merged now. Sorry for the break.