cmd/go: `go list -json -e` does not store location for invalid import path

[aykevl]

Go version

go version go1.23.1 linux/arm64

Output of go env in your module/workspace:

GO111MODULE=''
GOARCH='arm64'
GOBIN=''
GOCACHE='/home/ayke/.cache/go-build'
GOENV='/home/ayke/.config/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFLAGS=''
GOHOSTARCH='arm64'
GOHOSTOS='linux'
GOINSECURE=''
GOMODCACHE='/home/ayke/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='linux'
GOPATH='/home/ayke'
GOPRIVATE=''
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/usr/local/go1.23.1'
GOSUMDB='sum.golang.org'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/usr/local/go1.23.1/pkg/tool/linux_arm64'
GOVCS=''
GOVERSION='go1.23.1'
GODEBUG=''
GOTELEMETRY='local'
GOTELEMETRYDIR='/home/ayke/.config/go/telemetry'
GCCGO='gccgo'
GOARM64='v8.0'
AR='ar'
CC='gcc'
CXX='g++'
CGO_ENABLED='1'
GOMOD='/dev/null'
GOWORK=''
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
PKG_CONFIG='pkg-config'
GOGCCFLAGS='-fPIC -pthread -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=/tmp/go-build3054841504=/tmp/go-build -gno-record-gcc-switches'

What did you do?

I have the following invalid Go file

package main

import _ "#"

func main() {
}

I ran go list -json -e importpath.go on it, to see the loader error.

What did you see happen?

The JSON contains this part:

        "Error": {
                "ImportStack": [],
                "Pos": "",
                "Err": "/home/ayke/tmp/importpath.go:3:8: invalid import path: #"
        }

That's an error, of course, but the Pos field is not set even though go list clearly knows the source location (it's stored in the error message itself).

What did you expect to see?

I expected an output like this:

        "Error": {
                "ImportStack": [],
                "Pos": "importpath.go:3:8",
                "Err": "invalid import path: #"
        }

That is, the position information should be in Pos and the path should be relative and not absolute. For example, when setting the import path to one that doesn't exist, the error looks like this:

        "Error": {
                "ImportStack": [
                        "command-line-arguments"
                ],
                "Pos": "importpath.go:3:8",
                "Err": "no required module provides package foo.bar: go.mod file not found in current directory or any parent directory; see 'go help modules'"
        }

[gabyhelp]

Related Issues and Documentation

• x/tools/go/packages: 'go list -e -json' for a directory without .go source files doesn't show module-relative import path #33157 (closed)
• cmd/go: "no go files in \<dir>" error missing directory with list -json=\<fields> if fields doesn't contain Dir #64946 (closed)
• cmd/go: go list reports a mangled ImportPath for a relative path that is not a valid Go package #36008 (closed)
• cmd/go: strange attribution of missing imports #65335
• cmd/go: bad error message for local imports in module mode #47088
• cmd/go: no Module information in list -e output after any error loading package #44287 (closed)
• cmd/go: go list -e -json with syntax error behaves differently in test and non-test files #28491 (closed)
• cmd/go: clarify error message when importing a package that could be (but isn't) in the main module #34491
• cmd/go: list -e -json [absolute directory outside gopath] fails #34273 (closed)
• cmd/go: go list -m error is confusing when go.mod lacks module directive #37264 (closed)

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[aykevl]

Interestingly, @gabyhelp didn't show exact duplicates but does show this bug has been around for a while: it's also visible in #28491.

[timothy-king]

CC @matloob, @samthanawalla.