Proper way to vendor dependencies?

[lRespublica]

What is your question?
I need to build a program locally using cabal-install without internet access.

The build environment only includes GHC and cabal-install; no additional packages are installed. Therefore, all build dependencies must be available locally in some form.

Many modern statically linked languages (such as Rust and Go) provide a dependency vendoring mechanism to address this issue. Is it possible to achieve something similar using the native cabal-install tools?

System information

• GNU/Linux
• cabal - 3.14.2.0
• GHC - 9.6.6

Additional context
For my purposes, I wrote a small script that creates a local repository with all the required package dependencies.

https://github.com/lRespublica/cabal-vendor

However, I’m still running into a few issues. For example, it's not possible to specify a relative path for the repository location, so I have to resort to using sed hacks during the build process - which isn't ideal.

That’s why I’m asking this question here - maybe I’m going about this the wrong way.

[philderbeast]

There's a section in the source guide on vendoring. If you have local source code repositories for all of the dependencies then a cabal.project with local paths will pick up the dependencies locally.

source-repository-package
  type: git
  location: /home/... -- full path to local git repo with dependency

packages: .

You could have two project too, one for local offline use and another for when online.

[lRespublica]

Yes, I saw it, but it doesn't support automatic dependency resolution - only manual downloading of packages. On top of that, it requires editing the cabal.project file, which feels just as hacky as setting up a local repository.

[philderbeast]

I don't think we have an automatic way of vendoring with cabal so added a feature request, #10935.