:GoDebugStart or Test "could not determine package name"

[sebastianst]

What did you do?

Run :GoDebugStart or :GoDebugTest while the active buffer was in any of the following two go source files:

package gotest

import "fmt"

func main() {
	fmt.Println("vim-go")
}

package gotest

import "testing"

func TestMain(t *testing.T) {
	main()
}

What did you expect to happen?

The debugger to open

What happened instead?

vim prints the error "could not determine package name"

Configuration:

• vim-go version: 3e9a292 (2019-04-26)
• vimrc you used to reproduce:

call plug#begin('~/.vim/bundle')
Plug 'fatih/vim-go'
call plug#end()

• Vim version (first three lines from :version): NVIM v0.3.5, Build type: Release, LuaJIT 2.0.5
• Go version (go version): go version go1.12.4 linux/amd64
• Go environment (go env):

GOARCH="amd64"
GOBIN=""
GOCACHE="/home/seb/.cache/go-build"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOOS="linux"
GOPATH="/home/seb/go"
GOPROXY=""
GORACE=""
GOROOT="/usr/lib/go"
GOTMPDIR=""
GOTOOLDIR="/usr/lib/go/pkg/tool/linux_amd64"
GCCGO="gccgo"
CC="gcc"
CXX="g++"
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 -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build336271311=/tmp/go-build -gno-record-gcc-switches"

[bhcleek]

What does :echo getcwd() report?

What is the path to the files?

Have you updated delve recently (:GoUpdateBinaries dlv)?

[sebastianst]

cwd: /home/seb/tmp/gotest
files are home/seb/tmp/gotest/gotest{,_test}.go
I've updated all binaries. Still the same error.

[bhcleek]

It doesn't know the package name, because they're neither in the $GOPATH nor is there a go.mod file.

[sebastianst]

ah sure. but I have the same problem in an actual go.mod enabled repo. I'll update the test.
BTW seems to be pretty similar to #2236

[sebastianst]

OK I added the following go.mod

module github.com/sebastianst/gotest

go 1.12

and now :GoDebugTest works in the minimal example. But it still doesn't work in my big repo, where I actually encounter the problem. I'll try to reproduce the error.

[bhcleek]

I've only seen a few cases where :GoDebug or :GoDebugTest will show a could not determine package name:

1. when trying to debug a package that is outside of GOPATH and doesn't contain a go.mod.
2. when go list fails for some reason.

I've resolved the former in #2269. I don't know if it will resolve your issue or not since we don't know how to replicate your issue, but it seems worth a shot.

[sebastianst]

I suddenly cannot reproduce the bug, sorry for the confusion.