package main

import (
    "fmt"

    yaml "gopkg.in/yaml.v2"
)

var e = yaml.Encoder{}

func init() { fmt.Printf("p1: Type: %T\n", e) }

func main() {}

package main

import "plugin"

func main() {
    if _, err := plugin.Open("../p1/p1.so"); err != nil {
        panic(err)
    }
    if _, err := plugin.Open("../p2/p2.so"); err != nil {
        panic(err)
    }
}

#!/bin/bash
set -e

GOPATH=~/go
p1=$PWD/p1
p2=$PWD/p2
main=$PWD/main

rm -f $p1/p1.so $p2/p2.so
GO111MODULE=on go clean -modcache
go clean -cache

# init vendoring
cd $p1 && GO111MODULE=on go mod vendor
cd $p2 && GO111MODULE=on go mod vendor

echo -e "package yaml\n\nimport \"fmt\"\nfunc init() { fmt.Println(\"Init yaml (p1)\") }" > $p1/vendor/gopkg.in/yaml.v2/init.go
echo -e "package yaml\n\nimport \"fmt\"\nfunc init() { fmt.Println(\"Init yaml (p2)\") }" > $p2/vendor/gopkg.in/yaml.v2/init.go

# GOPATH + vendoring
echo -n "GOPATH+vendoring:"
cd $p1 && GO111MODULE=off go build -buildmode=plugin -n 2>&1 | grep '#' | grep gopkg.in/yaml

cd $p1 && GO111MODULE=off go build -buildmode=plugin 2>/dev/null >/dev/null
cd $p2 && GO111MODULE=off go build -buildmode=plugin 2>/dev/null >/dev/null
cd $main && GO111MODULE=off go run main.go

# GOMOD + vendoring
echo -n "GOMOD+vendoring:"
cd $p1 && GO111MODULE=on go build -buildmode=plugin -mod=vendor -n 2>&1 | grep '#' | grep gopkg.in/yaml

cd $p1 && GO111MODULE=on go build -buildmode=plugin -mod=vendor 2>/dev/null >/dev/null
cd $p2 && GO111MODULE=on go build -buildmode=plugin -mod=vendor 2>/dev/null >/dev/null
cd $main && GO111MODULE=off go run main.go

Init yaml (p1)
p1: Type: yaml.Encoder
Init yaml (p2)
p2: Type: yaml.Encoder

go: finding gopkg.in/yaml.v2 v2.2.1
go: finding gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405
go: downloading gopkg.in/yaml.v2 v2.2.1
go: finding gopkg.in/yaml.v2 v2.2.0
go: downloading gopkg.in/yaml.v2 v2.2.0
GOPATH+vendoring:# plugin/p1/vendor/gopkg.in/yaml.v2
Init yaml (p1)
p1: Type: yaml.Encoder
Init yaml (p2)
p2: Type: yaml.Encoder
GOMOD+vendoring:# gopkg.in/yaml.v2
Init yaml (p1)
p1: Type: yaml.Encoder
panic: plugin.Open("../p2/p2"): plugin was built with a different version of package gopkg.in/yaml.v2

goroutine 1 [running]:
main.main()
        /home/oszika/go/src/plugin/main/main.go:10 +0x97
exit status 2