Question

I have a lot perl code that does different things in test and production, and I want to lock my code to specific versions of CPAN modules in case there are some changes to some of them in the future which may possibly break my code.

So I want to use specific versions of all the modules I use. By use I mean

use XML::Smart 

Answer 1

To use specific module refer only

use only MyModule => 0.30;

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Also to print error if module version you want is above to currently installed one
You can say

use XML::Smart v1.6.9;

or

use XML::Smart 1.6.9;

or
for backward compatibility

use XML::Smart 1.006_009;  

With reference from perldoc :

• use Module VERSION LIST
• use Module VERSION
• use Module LIST
• use Module
• use VERSION

If the VERSION argument is present between Module and LIST, then the
use will call the VERSION method in class Module with the given
version as an argument. The default VERSION method, inherited from the
UNIVERSAL class, croaks if the given version is larger than the value
of the variable $Module::VERSION .