GameMaker (2.3)



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GMAssert is a library containing useful assertions for debugging and automated unit testing. You can use it to alert you to undesirable runtime conditions, pause the debugger at that point for further inspection, or quickly test code for expected behaviour.


See the Wiki section on the official GitHub repository.

GMAssert is 100% open source!

Bug reports and contributions welcome on the official GitHub repository.

End User Licence Agreement (EULA).

Age Rating: 4+


GMS2 - Version 2.0.1. Published May 11, 2019

Resolving Marketplace download error.

GMS2.3 - Version 2.2.3. Published July 17, 2022

This is a minor maintenance release for 2022.6's addition of Feather and the ref type.


  • Added debug value handler for the ref type and provisions for future new types.

Bug Fixes

  • Fix declared return types and argument counts for the following functions:
    • __gma_debug_value__
    • assert_doesnt_contain_exact_2d
  • Fix some Feather complaints on the test suite
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