x/tools/go/packages: Load returned packages with errors when specifying GOOS

[hajimehoshi]

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

$ go version
$ go version
go version go1.13.5 darwin/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
$ go env
GO111MODULE=""
GOARCH="amd64"
GOBIN=""
GOCACHE="/Users/hajimehoshi/Library/Caches/go-build"
GOENV="/Users/hajimehoshi/Library/Application Support/go/env"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GONOPROXY=""
GONOSUMDB=""
GOOS="darwin"
GOPATH="/Users/hajimehoshi/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/usr/local/go"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/local/go/pkg/tool/darwin_amd64"
GCCGO="gccgo"
AR="ar"
CC="clang"
CXX="clang++"
CGO_ENABLED="1"
GOMOD=""
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 -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/var/folders/ht/ky_bwgzs4bd5z1hh02k34x_h0000gn/T/go-build430597543=/tmp/go-build -gno-record-gcc-switches -fno-common"

What did you do?

Created these files in one directory.

go.mod:

module example.com/m

go 1.13

require golang.org/x/tools v0.0.0-20200114052453-d31a08c2edf2 // indirect 

main.go:

// +build ignore                                                                                                                                                                                                                              

package main

import (
        "fmt"
        "os"

        "golang.org/x/tools/go/packages"
)

func main() {
        cfg := &packages.Config{
                 Mode: packages.NeedName | packages.NeedFiles |
                        packages.NeedImports | packages.NeedDeps |
                        packages.NeedTypes | packages.NeedSyntax | packages.NeedTypesInfo,
                Env: append(os.Environ(), "GOOS=android", "CGO_ENABLED=1"),
        }

        allPkg, err := packages.Load(cfg, ".")
        if err != nil {
                panic(err)
        }
        for _, pkg := range allPkg {
                if len(pkg.Errors) > 0 {
                        panic(fmt.Sprintf("%v", pkg.Errors))
                }
        }
}

c.go:

package lib

import "C"

What did you expect to see?

No error

What did you see instead?

$ gl clean -cache && go run main.go
panic: [/Users/hajimehoshi/test/cgo/c.go:3:8: could not import C (no metadata for C)]

goroutine 1 [running]:
main.main()
        /Users/hajimehoshi/test/cgo/main.go:24 +0x2c6
exit status 2

This is similar to #36441

[hajimehoshi]

CC @matloob

[hyangah]

If GOOS is not specified, does it work? I wonder if this is the same issue as #36441.

[hajimehoshi]

Hmm, I thought yes, but it looks like this depends on the cache state. Let me double check.

[hajimehoshi]

Oops, now I found this issue even without GOOS. Then this is the same as #36441.

[hajimehoshi]

Removing packages.ModeTypes was necessary to reproduce the issue.

[hajimehoshi]

Updated the first comment, but I'm fine to close this marking 'duplicated'.

[hajimehoshi]

Now I realized I omitted packages.Need*, and this was wrong. I updated the issue again. Sorry for the confusion.

If GOOS is not specified, does it work? I wonder if this is the same issue as #36441.

Then yes it worked without GOOS. This can be reproduced when specifying various packages.Mode* values. This sounds a different issue from #36441.

[hajimehoshi]

I'm taking a look at this.

[gopherbot]

Change https://golang.org/cl/214738 mentions this issue: go/packages: ignore importing C