Vendoring with go mod vendor leads to "fatal error: 'config.h' file not found"

[mattfenwick]

Note: apologies if this issue has been reported before, or if there's a common solution to this problem -- it's the first time I've ever run into vendoring issues with a module including C source code so I'm still researching what's going on!

This could also be an issue with go mod vendor or my understanding of it.

---

I'm on Mac OS X 10.14.6.

When I vendor in graphviz using go mod vendor, I get a missing C header error:

# github.com/goccy/go-graphviz/internal/ccall
vendor/github.com/goccy/go-graphviz/internal/ccall/ccall.go:27:10: fatal error: 'config.h' file not found
#include "config.h"
         ^~~~~~~~~~
1 error generated.

I'm on graphviz 0.0.6:

✗ grep -i graphviz go.sum
github.com/goccy/go-graphviz v0.0.6 h1:sCT69fmH2KKsObVfsozYyKXxrqmIfo3SyHZs72xkgxs=
github.com/goccy/go-graphviz v0.0.6/go.mod h1:wXVsXxmyMQU6TN3zGRttjNn3h+iCAS7xQFC6TlNvLhk=

Here's what gets vendored in -- none of the headers:

✗ tree vendor/github.com/goccy/go-graphviz/        
vendor/github.com/goccy/go-graphviz/
├── LICENSE
├── README.md
├── cdt
│   └── cdt.go
├── cgraph
│   ├── attribute.go
│   └── cgraph.go
├── go.mod
├── go.sum
├── graphviz.go
├── gvc
│   ├── gvc.go
│   ├── image_renderer.go
│   └── renderer.go
├── internal
│   └── ccall
│       ├── builtin.c
│       ├── ccall.go
│       ├── cdt.c
│       ├── cdt.go
│       ├── cgraph.c
│       ├── cgraph.go
│       ├── circogen.c
│       ├── common.c
│       ├── common.go
│       ├── dotgen.c
│       ├── expat.c
│       ├── expat.go
│       ├── fdpgen.c
│       ├── gvc.c
│       ├── gvc.go
│       ├── label.c
│       ├── neatogen.c
│       ├── ortho.c
│       ├── osage.c
│       ├── pack.c
│       ├── patchwork.c
│       ├── pathplan.c
│       ├── plugin.c
│       ├── rbtree.c
│       ├── sfdpgen.c
│       ├── sparse.c
│       ├── twopigen.c
│       └── xdot.c
└── option.go

When I just rm -r vendor, this problem goes away and everything works fine. (Unfortunately, I may be forced to vendor :( )

[dmitshur]

This is likely similar to go-gl/glfw#251. There needs to be at least one .go file in a directory for it to be considered a Go package and source files to be included by vendor.

[goccy]

I am trying to solve this problem by writing the header content directly in the Go file ( cgo section ) .

[bogdanprodanj]

I've forked this repo and added dummy files so go mod vendor will include C files and it worked. I can create PR to fix this issue as a workaround for now

[yashbhutwala]

@bogdanprodanj do you have cycles to submit the PR?

[joelanford]

I just submitted a #37, which seems to resolve this issue.