Hi,

Here's a new version of the patch.  The only change is: I modified the
tests (tests/graph.scm and tests/profiles.scm) so that they also use the
package-full-name procedure's new #:delimiter keyword argument when
necessary.  I intended to do that from the start, but I forgot.

Alex Kost <alezost@gmail.com> writes:

> Chris Marusich (2018-04-09 23:38 -0700) wrote:
>
> [...]
>> Because I changed the package-full-name procedure, this also fixes the
>> package names in other places, such as graphs produced by "guix graph".
>
> I recall there was some discussion about 'package-full-name' in the past
> but I remember nothing about it :-)
>
> Well, maybe it is not relevant at all, but I've found there was a
> proposition to use "@" in 'package-full-name' and it is still not used
> there.  Look at:
>
>   http://lists.gnu.org/archive/html/guix-devel/2016-04/msg01141.html

Yes, we need to be careful.  The most obvious problem I encountered was
that the Guix daemon prohibits "@" in store item names (which I learned
only after attempting to change the delimiter everywhere and then
running some tests).  However, my patch does not put the "@" symbol into
store item names.  In fact, to be extra clear, I've added a comment to
the package->bag procedure to explain why we can't use "@" there.

I think the risk is fairly low that something in Guix itself will
malfunction if we make this change, since I've looked at the call sites
for package-full-name (in the guix Git repo only), I've run "make check"
successfully, and I've verified manually that a handful of guix commands
still function correctly.  But you never really know until you try.  We
should probably still check in some other places before changing the
default delimiter from "-" to "@".  For example, we should probably
check at least the following places:

* Hydra
* Cuirass
* Emacs-Guix

Where else should we check?

If it's too risky, we can always make the default delimiter "-" and only
change it to "@" in those places where we really need to (e.g., the
package->recutils procedure in (guix ui), to fix this specific bug
report).  What do you think?

-- 
Chris