x/tools/go/packages: Crash on Go 1.10.x with cgo disabled.

[klauspost]

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

$ go version
go version go1.10.7 linux/amd64

Does this issue reproduce with the latest release?

With latest x/tools/go/packages, yes, but the issue doesn't show up when using Go 1.11.x

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

go env Output

$ go env
GOARCH="amd64"
GOBIN=""
GOCACHE="/home/klaus/.cache/go-build"
GOEXE=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOOS="linux"
GOPATH="/home/klaus/gopath"
GORACE=""
GOROOT="/usr/local/go"
GOTMPDIR=""
GOTOOLDIR="/usr/local/go/pkg/tool/linux_amd64"
GCCGO="gccgo"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
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-build445057936=/tmp/go-build -gno-record-gcc-switches"

What did you do?

Using staticcheck:

go get -u honnef.co/go/tools/...

Checking a package, but disabling cgo:

$GOPATH/test/main.go:

package main

import (
	"fmt"
)

func main() {
	fmt.Println("...")
}

$GOPATH/test/main_test.go:

package main_test

import (
	"os/user"
	"testing"
)

func TestSomething(t *testing.T) {
	t.Log(user.Current())
}

Execute: env CGO_ENABLED=0 staticcheck test

What did you expect to see?

Successful inspection.

What did you see instead?

Crash in the package loader:

klaus@ubuntu:~/gopath/src/test$ env CGO_ENABLED=0 staticcheck test
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x8 pc=0x633c0a]

goroutine 1 [running]:
golang.org/x/tools/go/packages.createTestVariants.func1(0x0, 0xc420242f80)
        /home/klaus/gopath/src/golang.org/x/tools/go/packages/golist_fallback.go:260 +0x6a
golang.org/x/tools/go/packages.createTestVariants.func1(0xc4202a6460, 0xc420242f80)
        /home/klaus/gopath/src/golang.org/x/tools/go/packages/golist_fallback.go:264 +0x179
golang.org/x/tools/go/packages.createTestVariants(0xc420104780, 0xc42025e0e0, 0xc42025e540)
        /home/klaus/gopath/src/golang.org/x/tools/go/packages/golist_fallback.go:293 +0x389
golang.org/x/tools/go/packages.golistDriverFallback(0xc4200efa48, 0xc420102320, 0x1, 0x1, 0x0, 0x9f6640, 0xc420102310)
        /home/klaus/gopath/src/golang.org/x/tools/go/packages/golist_fallback.go:245 +0x76a
golang.org/x/tools/go/packages.goListDriver.func2(0xc4200efa48, 0xc42009afb0, 0x1, 0x1, 0xffffffffffffffff, 0x1, 0x20)
        /home/klaus/gopath/src/golang.org/x/tools/go/packages/golist.go:133 +0xce
golang.org/x/tools/go/packages.goListDriver(0xc4200efa48, 0xc4200ae010, 0x1, 0x1, 0xc4200efa40, 0xc4200efa70, 0xc4200efaa0)
        /home/klaus/gopath/src/golang.org/x/tools/go/packages/golist.go:144 +0xa7b
golang.org/x/tools/go/packages.defaultDriver(0xc4200efa48, 0xc4200ae010, 0x1, 0x1, 0x176bae2b017f, 0xc411a91ce0, 0x11a91ce0004455c7)
        /home/klaus/gopath/src/golang.org/x/tools/go/packages/packages.go:187 +0x68
golang.org/x/tools/go/packages.Load(0xc42006b830, 0xc4200ae010, 0x1, 0x1, 0x0, 0x98ad0a, 0x6, 0xc5d800, 0xc42006b770)
        /home/klaus/gopath/src/golang.org/x/tools/go/packages/packages.go:172 +0x6f
honnef.co/go/tools/lint/lintutil.Lint(0xc4200ca6c0, 0x4, 0x6, 0xc4200ae010, 0x1, 0x1, 0xc420243e30, 0x410443, 0x8f8d60, 0x8c8980, ...)
        /home/klaus/gopath/src/honnef.co/go/tools/lint/lintutil/util.go:277 +0x2a0
honnef.co/go/tools/lint/lintutil.ProcessFlagSet(0xc4200ca6c0, 0x4, 0x6, 0xc4200ca660)
        /home/klaus/gopath/src/honnef.co/go/tools/lint/lintutil/util.go:178 +0x99b
main.main()
        /home/klaus/gopath/src/honnef.co/go/tools/cmd/staticcheck/staticcheck.go:29 +0x2f2
klaus@ubuntu:~/gopath/src/test$

Seems this error was found in #28040 - but maybe was assumed to be a flaky test?

[klauspost]

Changing this loop to check the imports like this:

		for _, imp := range p.Imports {
			if allPkgs[imp.ID] == nil {
				fmt.Printf("for %s: imported package %s doesn't exist\n", p.ID, imp.ID)
				continue
			}
			if needsVariantRec(allPkgs[imp.ID]) {

Prints out: for os/user: imported package runtime/cgo doesn't exist

I haven't been able to create a simple reproduction case, though.

[klauspost]

Got a reproducer. Updated first post.

Seems to be the additional import loading from tests.

[bradfitz]

/cc @heschik @matloob @ianthehat @stamblerre

[matloob]

We no longer support Go 1.10.

Marking obsolete