Reported by Christopher Baines <mail@cbaines.net>
and Alex Kost <alezost@gmail.com>
at <https://lists.gnu.org/archive/html/guix-devel/2017-06/msg00290.html>.
* guix/discovery.scm (scheme-files): When ENTRY is a symlink that
doesn't end in '.scm', call 'stat' and recurse if it points to a
directory.
* tests/discovery.scm ("scheme-modules recurses in symlinks to
directories"): New test.
Fixes a regression introduced in
d27cc3bfaa.
Reported by Ricardo Wurmus <rekado@elephly.net>.
* guix/discovery.scm (scheme-files): Catch 'scandir*' system errors.
Return '() and optionally raise a warning upon 'system-error'.
* tests/discovery.scm ("scheme-modules, non-existent directory"): New
test.
On a command like:
guix environment --ad-hoc coreutils -- true
this reduces the number of 'stat' calls from 14.1K to 9.7K on my
setup (previously each getdents(2) call would be followed by one stat(2)
call per entry).
* guix/discovery.scm (scheme-files): Rewrite using 'scandir*'.
