bug#42601: Guix install bug: error: Unbound variable: ~S

[maxim . cournoyer]

Hi,

Bengt Richter <bokr@bokr.com> writes:

> Hi,
>
> On +2020-07-30 00:15:56 +0200, Ricardo Wurmus wrote:
>> 
>> Jan Wielkiewicz <tona_kosmicznego_smiecia@interia.pl> writes:
>> 
>> > Dnia 2020-07-29, o godz. 22:17:01
>> > Ricardo Wurmus <rekado@elephly.net> napisał(a):
>> >
>> >> 
>> >> “avr-toolchain” is a procedure, not a package.  Use
>> >> “avr-toolchain-4.9” or “avr-toolchain-5”.
>> >> 
>> >
>> > Success!
>> >
>> > What about the strange message though?
>> > "incorrect package definition" would be better.
>> 
>> “Unbound variable: ~S” looks like a format string with a placeholder
>> that didn’t get replaced with an actual value.  It would be marginally
>> better if it said “Unbound variable: avr-toolchain”.
>
> I suspect there are also bugs lurking in the exception-reporting chain between
> a (throw 'exception args ...) and the ultimate format statement that produces
> a message with "~S" in it. Perhaps one got fixed or avoided in the upgrade?

That would be my hunch too!  I had reported and tried to fix such problems
here: http://issues.guix.gnu.org/41956.  Still unresolved, it requires
more effort to be fixed properly (writing tests mostly).

Maxim