Re: package.el dependencies

[Artur Malabarba]

> The problem is we need to feed an alist of packages explicitely
> installed with their dependencies, so of course all packages installed
> prior this change will have to be reinstalled.
>
> The alist would looks like this:
>
> (setq packages-installed-explicitely
>       '((foo . (a b c d h))
>         (bar . (b d e))
>         (baz . (e f g))))
> where a b c... are dependencies.
>

I don't think we need an alist for that. Simply marking which packages
were installed explicitly in a plain list should be enough. The
dependency information is already available in `package-alist`,
there's no need to replicate it in this other variable. (In fact,
maybe the "instaleed explicitly" flag could be stored in
`package-alist' too, instead of its own list.)

Thus, when `foo' is removed, we loop through it's depedencies and
remove each package which is neither `installed-explicitly' nor the
dependency of something else.