lookaround/lookbehind regex that used to work not working anymore

[Artturin]

Describe the bug

Error: Failed to compile the regex pattern: "(?<=got.....)sha256.{45}" with error: error parsing regexp: invalid or unsupported Perl syntax: `(?<`

To Reproduce
Steps to reproduce the behavior:

1. run echo "got: sha256-L8wivKxb5OWfbnU/7Rs6GzecDLOCxAsukoO2Qj7egfU=" | kitten hints --program @ --type regex --regex '(?<=got.....)sha256.{45}'
2. See error

https://regex101.com/r/ieCHXq/1 shows that it should work with PCRE/2, if golang is chosen from the flavors then it fails so it looks like its not supported in go regexp :(

kitty 5b8b91b

[kovidgoyal]

The regex engine was changed to the one native to Go which doesnt
support these for performance reasons, IIRC.

[kovidgoyal]

Note that go has a regexp2 library that supports these, it should be a relatively simply patch to use that instead of the stdlib one to add support. I dont have much motivation for this, but PR is welcome.

[kovidgoyal]

You can also use the custom processing to do your matching in python using the python regex engine, without needing any patches.

[kovidgoyal]

Actually in your case you dont need the look behind at all. If the regex contains a single unnamed group the match will be just that groups contents. So you can use

got.*?sha256(.{45})

[Artturin]

Actually in your case you dont need the look behind at all. If the regex contains a single unnamed group the match will be just that groups contents. So you can use

got.*?sha256(.{45})

correct regex would be
got.*?(sha256.{45})

[Artturin]

Thanks for 65f8bb7.

You're awesome and one of the best open source developers!