feature: add non-plugin-dependencies in plugin spec

[chrisgrieser]

Did you check the docs?

• I have read all the lazy.nvim docs

Is your feature request related to a problem? Please describe.

lazy.nvim encourages you to put everything related to a plugin into the plugin spec, which makes the config much cleaner.

However, one thing not being "bundled" in the plugin spec are the non-plugin dependencies of a plugin. Those are, for example:

• debugpy for nvim-dap-python
• gh for octo.nvim
• jq for rest.nvim

Describe the solution you'd like

Simply stipulating that some key, e.g. extra_dependencies or non_plugin_dependencies should be used for this would already be enough. It wouldn't need to be lazy's job to install them (mason.nvim can do that), it would just need a "standardized" key.

Simply adding a row to the docs, defining that a certain key is to be used/reserved to list non-plugin-dependencies could already fulfill this FR; the rest would be up to other plugin devs. (similar to build.lua)

Describe alternatives you've considered

It is of course possible to manually add some key, e.g. masonDependencies to the plugin spec, and then get all those dependencies via require("lazy").plugins().

However, simply stipulating a plugin spec key would help in standardizing this and thus enable, so plugin devs would be more incentivized simply all use that one key prescribed by lazy.nvim.

Additional context

Having a way to express those dependencies in the plugin spec would be consistent with lazy.nvim's philosophy of bundling everything in the spec, make a plugin config more transparent, and also allow other plugins like for example mason with mason-tools-installer to add features to auto-install this those packages. (all the examples I listed are already available via mason).

This would, ultimately, make nvim configs a bit easier to set up for new users, and also make it a nvim config fully bootstrappable on a new machine.

[Shougo]

I think you can use cond.

https://github.com/folke/lazy.nvim/blob/main/doc/lazy.nvim.txt#L130

[chrisgrieser]

My FR is about being able to define non-plugin-dependencies. I fail to see how this is related to cond, which is about setting a condition when the plugin should be loaded.

[Shougo]

cond can check the dependency.

[chrisgrieser]

This FR is not about conditions for enabling plugins...

[folke]

Out of scope of lazy.nvim, but related to pkg.json.
Closing in favor of #910