Does GPL affect use of GitHub Actions?

Question

GitHub Actions is a continous-integration service by GitHub. You can create actions that other people use in order to e.g. test their code.

Let's say, I license a github action with GNU GPLv3.

Do people using this action need to open-source and license their whole repository with GPL or is this just the case if they e.g. fork my action?

They just include the action by adding something like this to a yml file:

- using: myusername/myaction

This does not redistribute my code or create binaries or something like that.

Answer 1

It probably depends:

This does not look like adding source code. It looks like what makefiles add to a repository: instructions how to build your programme from source, specifying tooling in the required order. So it is an indication of using a certain toollike certain flags for certain compilers, to use make or whatever is needed to build your programme from source.

The answer might change when the tool actually injections something like libraries do... (which use the LGPL for that very reason). So GPL might be a requirement for the build artefacts, unless your tool chooses to use the LGPL.

Anyhow: IANAL.