Re: [gentoo-portage-dev] [PATCH v5] Test for read-only filesystems, bail out during preinst if there are any which will be written to and display a useful error message. Fixes bug 378869.

[Mike Frysinger]

On Monday 20 January 2014 23:00:31 Chris Reffett wrote:
> +	if not ro_filesystems:
> +		return ro_filesystems
> +
> +	for directory in dir_list:
> +		for filesystem in ro_filesystems:
> +			if filesystem == directory:
> +				ro_filesystems_written.add(filesystem)
> +
> +	return ro_filesystems_written

is this just the intersection of two sets ?  so all this logic could be:
	return ro_filesystems ^ set(dir_list)
-mike