Error::...sertion(3)

📦
version 2.010001 · 14 versions
, in fedora 44

💖 Error::TypeTiny::Assertion — the manual, but make it make sense 💖

okay bestie, so this page is from the User Contributed Perl Documentation section of the manual (that's the (3) vibe), and it's all about Error::TypeTiny::Assertion 🦋

✨ NAME ✨

Error::TypeTiny::Assertion — the exception that gets thrown when a value fails a type constraint. literally the moment your value does NOT pass the vibe check. 💅

🌸 STATUS 🌸

This module is covered by the Type-Tiny stability policy. so it's official, it's sanctioned, it's got paperwork. 👑

🎀 DESCRIPTION 🎀

So. This exception gets thrown when a value fails a type constraint assertion. That's the whole thing. Your value walked up to the type constraint and the type constraint said "no 💀".

This package inherits from Error::TypeTiny — so go read that one for most of the documentation, it's giving main character. The major differences are listed right down below:

🌈 Attributes 🌈

  • type — the type constraint that was checked against. heads up though: weakened links are involved, so this may end up being undef. 😭
  • value — the value that was tested. the little guy. the one that failed. 🥺
  • varname — the name of the variable that was checked, if known. defaults to '$_'. ✨
  • attribute_name — if this exception was thrown as the result of an isa check or a failed coercion for a Moo attribute, then this will tell you which attribute (if your Moo is new enough). 🐄

(Hopefully one day this will support other OO frameworks.)

  • attribute_step — if this exception was thrown as the result of an isa check or a failed coercion for a Moo attribute, then this will contain either "isa check" or "coercion" to indicate which one went wrong (if your Moo is new enough). 🔥

(Hopefully one day this will support other OO frameworks.)

🦋 Methods 🦋

  • has_type, has_attribute_name, has_attribute_step — predicate methods. yes bestie, they check whether the thing exists. that's it, that's the method. ✅
  • message — overridden to add varname to the message if defined. so your error message gets a little name tag. 🏷️
  • explain — attempts to explain why the value did not pass the type constraint. returns an arrayref of strings providing step-by-step reasoning; or returns undef if no explanation is possible. it's basically the "so here's what happened" of error messages 🕵️♀️

💀 BUGS 💀

Please report any bugs to <https://github.com/tobyink/p5-type-tiny/issues>.

ngl if you found a bug, drop it in the issue tracker, the maintainer wants to know fr fr 🙈

👑 SEE ALSO 👑

Error::TypeTiny.

💜 AUTHOR 💜

Toby Inkster <tobyink@cpan.org>.

This software is copyright (c) 2013-2014, 2017-2025 by Toby Inkster.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself. slay, open source periodt 💅

⭐ DISCLAIMER OF WARRANTIES ⭐

THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.

okay so this part is in all caps for a reason bestie — no warranties, none, zero, nada. use it, love it, but don't come for anybody if it doesn't work out. 😭

and that's the whole page!! this was rendered by perl v5.42.0 on 2026-01-17, so if you're reading this from the future, hiii, hope the Perl is still perling 🫶✨

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