Devel::Assert - assertions for Perl >= 5.14


    use Devel::Assert; # release mode, won't perform checks

    assert(3 < 2); 

    use Devel::Assert 'on';

    assert(3 < 2); # oops, check your math


    use Devel::Assert; # import 'assert' function, but doesn't enable it
    use Devel::Assert 'on'; # import 'assert' function and enable it

    use Devel::Assert 'global'; # import 'assert' function and enable it in all later 'use Devel::Assert' imports
    use Devel::Assert::Global; # the same, can be used as perl -MDevel::Assert::Global

    use Devel::Assert 'off'; # import 'assert' function, but doesn't enable it, even when in 'global' mode


This module provides you with a C-like assert() function. And, like in C, it only is compiled in debug mode - it's completely removed together with it's arguments at compile time in release mode. That's useful to force functions' contracts during development without sacrificing production performance.

Think of an assert() being a test, but right inside your code:

    sub get_url {
        my ($self, $url, $cb) = @_;

        assert length $url;
        assert(ref($cb) eq 'CODE');


Failed assertions are reported by confess with failed test code embedded:

    Assertion 'ref $cb eq 'CODE'' failed at ...

This module doesn't use source filters or any other form of source text parsing, but instead relies on the generated optree analysis and manipulation.


This version significantly differs from 0.04 release. The main reason behind such radical change was to get rid of the Devel::Declare dependency and to pass all the parsing work to Perl itself (instead of creating own statement parser).


assertions - uses code attributes

Carp::Assert - requires annoying 'if DEBUG' suffix

PerlX::Assert - based on Devel::Declare


Sergey Aleynikov <>


Copyright (C) 2009, 2015 Sergey Aleynikov


This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.