usemove [was Re: [gentoo-dev] RFC: changing ssl use flag descriptions and unify behaviour]

[Brian Harring]

On Sun, Mar 28, 2010 at 01:03:43AM -0500, Doug Goldstein wrote:
> I seriously hate changing USE flags for the sake of changing use
> flags. This provides a moderate amount of annoyance for anyone that
> maintains more then one Gentoo box because they need to then tinker
> with their /etc/make.conf and /etc/portage/package.use to get
> everything right again. And oh no what if the one box is on ~arch and
> one isn't and what if one is x86 and one isn't. Its just such a
> configuration nightmare.
>
> So unless there's any real benefit, I'm against this.

I'm not arguing for arbitrary changes, but if the change makes sense 
and isn't trivial it should be done.

What is needed is to tweak the tools for such a move- specifically 
adding a new command to the update machinery (profiles/updates).  
Something roughly like

usemove [atom] original_flag new_flag

If an atom is specified, the move applies only to w/in that pkg; if no 
atom, it's a global shift in the configuration (meaning all ebuilds 
now use gtk instead of gtk2 for example).

Examples:

usemove gtk gtk2
usemove app-admin/gtkrellm gnutls ssl
usemove dev-cpp/sptk:3 gnutls ssl
usemove >=app-editors/emacs-22.3 gzip-el gzip

Etc.

Per the norm for updates, usual rules apply- since it's a string of 
delta commands, once a command is in there it cannot be changed in 
purpose (although folk can tweak existing commands to update for a 
final target, eg: A -> B, B -> C; changing it to A -> C, B -> C).


> Also two little side points... USE defaults happened in EAPI 1. And
> the method by which you're asking people to select would be nice if we
> had some method for saying USE X and Y are subset of USE A.

USE_EXPAND, roughly- I wouldn't say it's fully there, but it certainly 
would be where I'd start for any proposal...

~harring