plugin: panic: plugin was built with a different version of package

[juhwany]

Please answer these questions before submitting your issue. Thanks!

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

go version go1.11 darwin/amd64

Does this issue reproduce with the latest release?

Yes

What operating system and processor architecture are you using (go env)?

GOARCH="amd64"
GOBIN="/Users/juhwany/go_workspace/bin"
GOCACHE="/Users/juhwany/Library/Caches/go-build"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GOOS="darwin"
GOPATH="/Users/juhwany/go_workspace"
GOPROXY=""
GORACE=""
GOROOT="/usr/local/go"
GOTMPDIR=""
GOTOOLDIR="/usr/local/go/pkg/tool/darwin_amd64"
GCCGO="gccgo"
CC="clang"
CXX="clang++"
CGO_ENABLED="1"
GOMOD="/Users/juhwany/gos/go_server/go.mod"
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/mk/2tyywdsn0jq6l0vl8094tss80000gp/T/go-build380269681=/tmp/go-build -gno-record-gcc-switches -fno-common"

What did you do?

1. Clone the blow repo in each directory. (not under GOPATH)
   server (main program) : https://github.com/juhwany/go_server
   plugin : https://github.com/juhwany/go_plugin

2. On same machine, build server & plugin in each directory
   Build server : go build -o main
   Build plugin : go build -buildmode=plugin -o plugin.so

3. Copy plugin.so to server directory and run
   ./main

4. See error message when main program try to open plugin.

panic: plugin.Open("plugin"): plugin was built with a different version of package github.com/juhwany/go_server/v2/apis

What did you expect to see?

Main program should load plugin.so successfully.
I could not understand why it fails even though the referenced package version is same between main program and plugin.
Am I using plugin in wrong way?

What did you see instead?

plugin was built with a different version of package error message

[randall77]

Related (dup?) #26759 .

[juhwany]

@randall77

No. I think building environment is slightly different from #26759.
I didn't build main program and plugin under GOPATH and the above sample project uses Go module for specifying dependency package. Go version is also different.

[BryceDFisher]

I do think they are all related though, including #27062. I think it all boils down to changing (absolute) paths at build time between the plugin build and the app build.

[bcmills]

CC @ianlancetaylor @cherrymui

[tamasfe]

I'm not sure if anyone's already mentioned it, but putting the common(apis) package to a separate module outside the server one will work. It's definitely cumbersome, but can be used as a workaround until this issue is fixed.

[oszika]

The command "go list -m -json all" shows version of go_server on go_plugin, but it's not defined on go_server itself. I have a similar problem using multiples modules on the same repository using "replace" directive. I don't know how to have the same version of the module inside and outside the repository.

[oszika]

In #28983, @bcmills suggests to build plugins from within the main module.

// server/go.mod
module github.com/juhwany/go_server/v2
require github.com/juhwany/plugin v0.0.0
replace github.com/juhwany/plugin => ../go_plugin

$ go build -buildmode=plugin github.com/juhwany/plugin
$ go run main.go 
DoSomething called!

[jbrukh]

Just throwing in my two cents here. Both the @tamasf97 and @oszika are workarounds.

However, @tamasf97's workaround only works if you can factor the shared code out without creating a circular dependency (not always possible).

@oszika's workaround using the "replace" directive is pretty inconvenient for clients of the shared code, as you need that local repo.