When I run a command such as:

  guix challenge --verbose --diff=diffoscope gavl 2>&1 | tee gavl

It works for the most part, producing the diffoscope output, but ends
with a bunch of warnings regarding removing the temporary directory it
created to compare the files:

  warning: failed to delete /tmp/guix-directory.5TokII/share/doc: Permission denied
  warning: failed to delete /tmp/guix-directory.5TokII/share: Permission denied
  warning: failed to delete /tmp/guix-directory.5TokII: Directory not empty

The permissions on the directory are read-only, which is presumably why
it cannot remove them:

  $ ls -latr /tmp/guix-directory.5TokII/
  total 28
  dr-xr-xr-x   3 vagrant vagrant  4096 Dec 31  1969 share
  dr-xr-xr-x   3 vagrant vagrant  4096 Dec 31  1969 lib
  dr-xr-xr-x   3 vagrant vagrant  4096 Dec 31  1969 include
  dr-xr-xr-x   5 vagrant vagrant  4096 Dec 31  1969 .
  drwxrwxrwt 168 root    root    12288 Jun  5 09:28 ..


The warnings are at best distracting, and at worst end up effectively
making it impossible to see the diffoscope output without redirecting to
a file, as the source files can take up many many lines in the scroll
buffer.


live well,
  vagrant