Re: Can we increase the print width/column in daemon backtraces

[Ricardo Wurmus]

Marius Bakke <address@hidden> writes:

> Pierre Neidhardt <address@hidden> writes:
>
>> Marius Bakke <address@hidden> writes:
>>
>>> You can run it directly from a shell, and/or attach a debugger.
>>
>> Thanks for the tip.
>>
>> Any idea how to attach Geiser to it?
>
> The daemon is a C++ program, so I'm not sure that would work ...
>
> If you are trying to increase the trace width within a build expression,
> you probably just need to (setenv "COLUMNS" "200") in the builder.

A daemon built with this change prevents truncation in the Guile
builders (without having to modify the Guile builders):

diff --git a/nix/libstore/build.cc b/nix/libstore/build.cc
index 29266f1dd6..94609e07f5 100644
--- a/nix/libstore/build.cc
+++ b/nix/libstore/build.cc
@@ -2247,6 +2247,7 @@ void DerivationGoal::runChild()
         Strings envStrs;
         foreach (Environment::const_iterator, i, env)
             envStrs.push_back(rewriteHashes(i->first + "=" + i->second, 
rewritesToTmp));
+       envStrs.push_back("COLUMNS=1024");
 
         /* If we are running in `build-users' mode, then switch to the
            user we allocated above.  Make sure that we drop all root

-- 
Ricardo