install from lockfile doesn't respect pkgs_dirs

[alchzh]

a command like micromamba install --name explicit --file conda-lock.yml ignores configured pkgs_dirs due to 7ea1ab9 and

mamba/libmamba/src/api/install.cpp

Line 568 in f32b42e

fs::u8path pkgs_dirs(Context::instance().root_prefix / "pkgs");

I would like to use lockfiles in tandem with a shared package cache on my server environment for large environment updates.

Is there a reason for the current behavior?

[hmaarrfk]

Could it be that this is stopping our offline installs at conda-forge? xref: conda-forge/miniforge#419

[hmaarrfk]

Is the fix that that the line should look more like:

mamba/libmamba/src/api/install.cpp

Line 422 in f32b42e

MultiPackageCache package_caches(ctx.pkgs_dirs);

[alchzh]

I'm guessing there was a decision made with good reason to find the pkgs for manually instead of like that. @wolfv ?

[hmaarrfk]

I think it is causing us to also create a random folder in the user's directory: conda-forge/miniforge#420

[alchzh]

Thank you for getting this in!