bug#56845: unclear error message: No route to host

bug#56845: unclear error message: No route to host

[Csepp]

```
guix pull -v3 --cores=1      
guix pull: error: failed to load '/home/raingloom/.config/guix/channels.scm': No route to host
```

My channels.scm mentions at least 3 hosts by name and indirectly uses
ci.guix.gnu.org via channel-with-substitutes-available.

It's quite possible this is more a Guile issue, but then again, Guix
should give a clear stack trace about which function the error
originates from.

bug#56845: unclear error message: No route to host

[Ludovic Courtès]

Hi,

Csepp <raingloom@riseup.net> skribis:

> guix pull -v3 --cores=1      
> guix pull: error: failed to load '/home/raingloom/.config/guix/channels.scm': No route to host
> ```
>
> My channels.scm mentions at least 3 hosts by name and indirectly uses
> ci.guix.gnu.org via channel-with-substitutes-available.

‘channel-with-substitutes-available’ failed due to a networking issue,
which is where “No route to host” comes from (it means that
ci.guix.gnu.org could not be reached from your machine).

> It's quite possible this is more a Guile issue, but then again, Guix
> should give a clear stack trace about which function the error
> originates from.

Yeah, ‘load*’ should better discriminate on the type of issues: issues
such as “File not found” (where displaying a stack trace would be
wrong), and issues caused by actually running the code.  Right now it
loads the file at once (meaning open + read + eval), so it doesn’t have
a sufficiently detailed vision.

Ludo’.