cmd/go: workspace recursive add panics on permission errors

[sding3]

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

$ go version
go version devel go1.19-0652274c10 Sat Mar 26 01:27:54 2022 +0000 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=""
GOARCH="amd64"
GOBIN=""
GOCACHE="/home/shang/.cache/go-build"
GOENV="/home/shang/.config/go/env"
GOEXE=""
GOEXPERIMENT=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOINSECURE=""
GOMODCACHE="/home/shang/go/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="linux"
GOPATH="/home/shang/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/home/shang/go/src/go"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/home/shang/go/src/go/pkg/tool/linux_amd64"
GOVCS=""
GOVERSION="devel go1.19-0652274c10 Sat Mar 26 01:27:54 2022 +0000"
GCCGO="gccgo"
GOAMD64="v1"
AR="ar"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD="/dev/null"
GOWORK="/tmp/reproduce-issue/go.work"
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-build2978051223=/tmp/go-build -gno-record-gcc-switches"

What did you do?

mkdir /tmp/reproduce-issue
cd /tmp/reproduce-issue

mkdir dir
chmod 000 dir

go work init
go work use -r .

What did you expect to see?

Expected go work use -r . to not panic.

What did you see instead?

Saw the following panic:

go: stat /tmp/reproduce-issue/dir/go.mod: permission denied
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x28 pc=0x81ff85]

goroutine 1 [running]:
cmd/go/internal/workcmd.runUse.func1({0xc0000a89b0?, 0xc0001500c0?})
        /usr/local/go/src/cmd/go/internal/workcmd/use.go:97 +0x165
cmd/go/internal/workcmd.runUse.func2({0xc0000a89b0, 0x3}, {0xae1500, 0xc000146c30}, {0x5?, 0xc0000a89ab?})
        /usr/local/go/src/cmd/go/internal/workcmd/use.go:126 +0x113
cmd/go/internal/fsys.walk({0xc0000a89b0, 0x3}, {0xae1500, 0xc000146c30}, 0xc0000f1998)
        /usr/local/go/src/cmd/go/internal/fsys/fsys.go:413 +0xba
cmd/go/internal/fsys.walk({0x7ffd30b97189, 0x1}, {0xae1500, 0xc000146a90}, 0xc0000f1998)
        /usr/local/go/src/cmd/go/internal/fsys/fsys.go:427 +0x1dc
cmd/go/internal/fsys.Walk({0x7ffd30b97189, 0x1}, 0xc0000f1998)
        /usr/local/go/src/cmd/go/internal/fsys/fsys.go:443 +0x85
cmd/go/internal/workcmd.runUse({0xae0ac0?, 0xc0000a8000?}, 0xc0000d45b8?, {0xc0000be040, 0x1, 0x3?})
        /usr/local/go/src/cmd/go/internal/workcmd/use.go:117 +0x97f
main.invoke(0xdbf780, {0xc0000be020, 0x3, 0x3})
        /usr/local/go/src/cmd/go/main.go:225 +0x34e
main.main()
        /usr/local/go/src/cmd/go/main.go:179 +0x7ce

[gopherbot]

Change https://go.dev/cl/395917 mentions this issue: cmd/go: fix panic in workspace recursive use

[bcmills]

Looks like the Gerrit CL was closed as a duplicate — is there anything left to be done here?

[sding3]

CL 394154 fixed this.