# Regarding anti cheat code error

**URL:** <https://forum.codecrafters.io/t/regarding-anti-cheat-code-error/7968>\
**Category:** General\
**Tags:** challenge:grep\
**Created:** [March 31, 2025, 9:33am UTC](https://forum.codecrafters.io/t/regarding-anti-cheat-code-error/7968 "2025-03-31T09:33:46Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Neelesh56789](https://yyz1.discourse-cdn.com/flex003/user_avatar/forum.codecrafters.io/neelesh56789/32/8324_2.png) [@Neelesh56789](https://forum.codecrafters.io/u/Neelesh56789)\
**Post date:** [March 31, 2025, 9:33am UTC](https://forum.codecrafters.io/t/regarding-anti-cheat-code-error/7968/1 "2025-03-31T09:33:46Z")

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I am getting this anti cheat code error even if all the test cases are passing, why?

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**Author:** ![andy1li](https://yyz1.discourse-cdn.com/flex003/user_avatar/forum.codecrafters.io/andy1li/32/10_2.png) [@andy1li](https://forum.codecrafters.io/u/andy1li)\
**Post date:** [March 31, 2025, 2:23pm UTC](https://forum.codecrafters.io/t/regarding-anti-cheat-code-error/7968/4 "2025-03-31T14:23:57Z")

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Hey @Neelesh56789, we’ve got anti-cheat test cases for preventing users from accidentally using built-in regex features or regex libraries (which would defeat the purpose of the  
challenge).

These tests aren’t perfect, sometimes it’s possible to implement something that’s not mentioned in the stage instructions that could cause these tests to fail.

Here’s our anti-cheat test for the grep challenge:  
[grep-tester/internal/anti\_cheat\_quantifiers.go at main · codecrafters-io/grep-tester · GitHub](https://github.com/codecrafters-io/grep-tester/blob/main/internal/anti_cheat_quantifiers.go).

These tests focus on quantifiers, which we expect most users wouldn’t have implemented in their own versions of grep, yet are readily handled by standard libraries.