debugging cycles in build

debugging cycles in build

[Dave Love]

I changed a package to have a "lib" output, which failed because it
detected a cycle (whereas it's OK with everything in "out").  Is there a
good way to debug that?  I couldn't easily find the code implementing
the check.

Re: debugging cycles in build

[Ludovic Courtès]

Dave Love <fx@gnu.org> skribis:

> I changed a package to have a "lib" output, which failed because it
> detected a cycle (whereas it's OK with everything in "out").  Is there a
> good way to debug that?

No good way unfortunately.  I usually build with -K and then do
something like:

  LC_ALL=C grep -r OUTPUT2 OUTPUT1

which kinda works, except if the reference comes from a symlink, in
which case you can do something like:

  tar cf O2.tar OUTPUT2
  grep OUTPUT1 O2.tar

and/or open O2.tar in Emacs with hexl-mode.

This is inconvenient but doable.

> I couldn't easily find the code implementing the check.

The check is done by guix-daemon, whose C++ code base is under nix/.

HTH!

Ludo’.