[Nix-dev] nixos-rebuild --show-trace should be default

[Marc Weber]

Excerpts from Eelco Dolstra's message of Thu Jan 07 11:12:14 +0100 2010:
> Hi,
> 
> Marc Weber wrote:
> 
> > Does someone mind my comitting this patch?
> 
> I disabled stacktraces by default because they're not very helpful (and rather
> intimidating) to the average user.

That's right. Let's assume there is an average user.
Let's assume he runs nixos-rebuild test.
Let's assume there is an error.
Let's assume he dosen't know what he did wrong.

What will he do?

He'll join either irc or mailinglist and ask: Help What's wrong?

What will you tell him ?

Run nixos-rebuild test --show-trace
because it *does* give you many hints about what was wrong.

If the output is too long ghc dev's have invented a way to "squash' a
lazy stack trace (whatever that is).

A description can be found here:
http://www.vimeo.com/6679381

However in the NixOS case it would be sufficient to shew the last 20
lines of the output..

Marc Weber