Doesn't Perl include current directory in @INC by default?

Question

I have never fully understood Perl's resolution of package names, but I always assumed that the following should always work, assuming you are executing myscript.pl from within the directory that contains it:

myscript.pl (contains the following statement: use Class1::Class2::Class3) Class1/     Class2/         Class3.pm (contains the following package declaration: package Class1::Class2::Class3;) 

However, this is not working in my code because Class3.pm cannot be located. Looking at @INC, it does not include the current directory, only various directories of my Strawberry Perl installation.

What is the recommended way to solve this? I suppose I could modify @INC, or I could start using FindBin, but I'm not sure which is best. I have inherited this code and am simply migrating it to a new location, but it doesn't look like the old code needed either such solution (I could be wrong, still looking...)

Answer 1

Perl doesn't search the current directory for modules or the script's directory for modules, at least not anymore. The current directory was removed from @INC in 5.26 for security reasons.

However, any code that relies on the current directory being in @INC was buggy far before 5.26. Code that did so, like yours, incorrectly used the current directory as a proxy for the script's directory. That assumption is often incorrect.

To tell Perl to look in the script's directory for modules, use the following:

use FindBin 1.51 qw( $RealBin ); use lib $RealBin; 

or

use Cwd qw( abs_path ); use File::Basename qw( dirname ); use lib dirname(abs_path($0)); 

Answer 2

Having . (the current directory) in @INC was removed in 5.26 for security reasons (CVE-2016-1238). Some Linux distributions have backported the change, so you might run into this problem even if you're using e.g. 5.24.