Can't exec "proj": No such file or directory

[shawnlaffan]

I've hit this error on a fresh Ubuntu 22.04.3 instance (via WSL2).

Can't exec "proj": No such file or directory at /home/shawn/.cpanm/work/1727936400.10110/PDL-2.093/Libtmp/Transform/Proj4/proj4.pd line 145.
ERROR from evaluation of /home/shawn/.cpanm/work/1727936400.10110/PDL-2.093/Libtmp/Makefile.PL: ERROR from evaluation of /home/shawn/.cpanm/work/1727936400.10110/PDL-2.093/Libtmp/Transform/Makefile.PL: ERROR from evaluation of /home/shawn/.cpanm/work/1727936400.10110/PDL-2.093/Libtmp/Transform/Proj4/Makefile.PL: proj -lP: No such file or directory at /home/shawn/.cpanm/work/1727936400.10110/PDL-2.093/Libtmp/Transform/Proj4/proj4.pd line 145.

The issue is that Alien::proj on this system is a share install. The proj utility is thus not in the system path and is not found.

pdl/Libtmp/Transform/Proj4/proj4.pd

Line 145 in 1038d63

my $text = do { open my $fh, '-|', qw(proj -lP) or die "proj -lP: $!"; local $/; <$fh> };

The fix is probably to check for Alien::proj->bin_dir and prepend it to the call if it is defined. Or it can be prepended to the path, which is currently done for Windows at Line 23.

[shawnlaffan]

Actually, that line can be replaced by this:

my $text = Alien::proj->run_utility ("proj", "-lP");

The run_utility method works for either system or share installs.

[mohawk2]

Perfect, I'll make that change now.

[mohawk2]

Could you try HEAD with the above-linked change? If that works, could you then close this issue? Obviously #498 is a slightly different deal.

[shawnlaffan]

This works now, but I should have added error checking to the suggested fix.

Something like this should do the trick:

my ($text, $stderr, $exit_code) = Alien::proj->run_utility ("proj", "-lP");
die "proj -lP error $exit_code. Error text is: $stderr" if $exit_code;

Errors should only happen when the installation has been messed with, e.g. system dependencies uninstalled after Alien::proj was built. Perhaps extra text could be added to that effect but I'll leave that call to you.

[mohawk2]

I thought it would be too complicated to try to guess the cause of any such failure. I've gone for a compromise, where it always warns any stderr, but then dies if there was an error exit-code.

Do you think this is fixed now?

[shawnlaffan]

That looks good to me.

[mohawk2]

Great, and thanks for the help! Please close the issue :-)