composer install only a specific package

[sadamczyk-eos]

I'm trying to install a single package based on it's version in the composer.lock in an automation script, to avoid having to install all of the project dependencies when all I need is just that single package.
I just tried running composer install foo/example-package, but it gives me an error:
Invalid argument foo/example-package. Use "composer require foo/example-package" instead to add packages to your composer.json.

Very unhelpfully composer install --help lists packages as an argument, but the description tells me, it shouldn't be used?
Why is it even listed as an argument then?

$ composer install --help
Usage:
  install [options] [--] [<packages>]...
  i

Arguments:
  packages    Should not be provided, use composer require instead to add a given package to composer.json.

Using composer require foo/example-package doesn't work as well, because

1. either the installed package version might not actually match the one in the composer.lock
2. or requires manual updating if I pinned the version with composer require foo/example-package:1.2.3.

Am I missing something, or is this actually not possible, and I will have to live with the drawbacks of either installing everything unnecessarily, using potentially mismatched version, or requiring manual updating?

The only other solution that comes to mind is parsing the composer.json or composer.lock with something like grep and using that as the version string to composer require.

I'm grateful for any ideas. :)

[Seldaek]

Yeah, we only support dependencies as a set of things. Installing a single dependency is typically meaningless so this is not supported. You can use composer show --lock --format=json to extract data and maybe run a require to create a new composer.json with a new vendor dir containing just the one dependency..

[sadamczyk-eos]

Alright, I understand. I'll try that then, thanks!