feat(trampoline): allow shared cache folder between users

[fransua]

Problem description

Hi,

To optimize resources, my coworkers and I would like to share the .cache/rattler folder across users in the same group. However, the permissions set by Pixi in this folder do not seem to respect the system's umask (which is 0002 in our case). As a result, group members are denied write access to files and directories created by other users, even though the group is correct.

I believe the root of the issue is here:

pixi/src/global/trampoline.rs

Lines 387 to 397 in c754587

	#[cfg(unix)]
	{
	use std::os::unix::fs::PermissionsExt;
	tokio_fs::set_permissions(self.path(), std::fs::Permissions::from_mode(0o755))
	.await
	.into_diagnostic()?;
	}
	Ok(())
	}

From what I can tell, std::fs::create_dir_all is used without adjusting permissions afterward, and the default mode of 0o755 ends up being applied regardless of the umask.

Could this be updated to either:
- explicitly apply 0o775 when creating group-shared directories
- or, ideally, respect the current process's umask when creating directories?

This would make sharing cache folders across users in the same group much easier and still safe.

Thanks!

François

[gzm55]

related issue and pr:

• Implement layered package caches conda/rattler#43
• feat: add support for layered package cache conda/rattler#1003

[baszalmstra]

So would this just entail setting the proper permission on that directory? Is that enough?

[lucascolley]

So would this just entail setting the proper permission on that directory? Is that enough?

gentle ping @fransua

[fransua-fcs]

sorry, yes! For our team it would be enough.