Re: bug#30854: 27.0.50; Speeding up package.el startup

[Stefan Monnier]

> Sysadmin can install packages for many users to share them, users have
> read priviledge, not write of course. Sysadmin would install/uninstall
> packages and a user would need to read autoloads.el from that shared
> system dirctory, and then maybe even from it's own?

The users may have some of the packages installed in their
~/.emacs.d/elpa which take precedence over the versions installed by the
sysadmin, and also their `package-load-list` may disable some of the
sysadmin-installed packages.  So you can't have a single concatenated
autoloads file for all the sysadmin-installed packages shared between
all the users.

So I think instead the package-quickstart file should come with a bit of
extra freshness info, e.g. the `mtime` of all the directories in
`package-directory-list` when it was created, so we can skip the
quickstart and mark it "needs-refresh" when one of the directories has
been modified (by (un)installing a package).


        Stefan