Michał Górny wrote:
> No, of course not. Otherwise, every package manager run would
> practically require it to re-validate all packages in the tree
> (possibly not only installed ones).
>
> Package manager must ensure the flags are valid when package is
> in the graph. I would think of IUSE_RUNTIME as a last-step action where
> packages were in the graph for rebuild already but the rebuild is
> disabled as being unnecessary.

That's what I thought, was just making sure we're on the same page.

> No, the USE flag list in vdb may be updated every time the package gets
> into the graph with changed runtime flags. I don't consider that
> necessary, however. Just a nice backwards compatibility feature for
> other applications looking at vdb.

'K

> Well, as I see it restricting is more of a policy than a technical
> requirement.

As long as we're clear on which it is, and what restrictions if any the 
PM can/should impose...

> But in the current form, the spec doesn't allow passing
> IUSE_RUNTIME flags to has_version() so we're on the safe side :P.

True.  Do we want to keep it that restrictive?