cmd/go: panic while running go mod tidy

[shoenig]

Please answer these questions before submitting your issue. Thanks!

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

$ go version
go version go1.11rc1 linux/amd64

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

$ go env
GOARCH="amd64"
GOBIN=""
GOCACHE="/home/hoenig/.cache/go-build"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOOS="linux"
GOPATH="/home/hoenig/Documents/indeed-go"
GOPROXY=""
GORACE=""
GOROOT="/opt/google/go"
GOTMPDIR=""
GOTOOLDIR="/opt/google/go/pkg/tool/linux_amd64"
GCCGO="gccgo"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD="/home/hoenig/Documents/indeed-go/src/indeed/gophers/3rdparty/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-build507642769=/tmp/go-build -gno-record-gcc-switches"

What did you do?

Ran go mod tidy. It crashed with:

$ go mod tidy
panic: runtime error: slice bounds out of range

goroutine 1 [running]:
cmd/go/internal/modload.(*mvsReqs).required(0xc0002ae1c0, 0xc000284c80, 0x17, 0x0, 0x0, 0xc0001314f8, 0x40f639, 0x8e8b40, 0xc0002aa278, 0xc000131598)
	/usr/local/go/src/cmd/go/internal/modload/load.go:835 +0x1232
cmd/go/internal/modload.(*mvsReqs).Required.func1(0xc000118444, 0x913fe0)
	/usr/local/go/src/cmd/go/internal/modload/load.go:765 +0x83
cmd/go/internal/par.(*Cache).Do(0xc0002ae1d8, 0x913fe0, 0xc000118420, 0xc000131708, 0xc0001318d0, 0xc000131810)
	/usr/local/go/src/cmd/go/internal/par/work.go:128 +0xd6
cmd/go/internal/modload.(*mvsReqs).Required(0xc0002ae1c0, 0xc000284c80, 0x17, 0x0, 0x0, 0xc0002ae1c0, 0x70, 0x68, 0x925c60, 0x0)
	/usr/local/go/src/cmd/go/internal/modload/load.go:764 +0x10f
cmd/go/internal/modcmd.modTidyGoSum.func1(0xc000284c80, 0x17, 0x0, 0x0)
	/usr/local/go/src/cmd/go/internal/modcmd/tidy.go:80 +0x10b
cmd/go/internal/modcmd.modTidyGoSum()
	/usr/local/go/src/cmd/go/internal/modcmd/tidy.go:87 +0x164
cmd/go/internal/modcmd.runTidy(0xd56020, 0xc0000a6080, 0x0, 0x0)
	/usr/local/go/src/cmd/go/internal/modcmd/tidy.go:66 +0x513
main.main()
	/usr/local/go/src/cmd/go/main.go:218 +0x7d4

[hajimehoshi]

I encountered the same error, I couldn't make a minimized case though.

[agnivade]

Duplicate of #27066. Fixed on tip.