Invalid regular expression: (?i): Invalid group

[cjxe]

Description:

When I type (?i) into a regex rule, then the runner throws an error.

Action version:

Latest version.

Platform:

• Ubuntu
• macOS
• Windows

Runner type:

• Hosted
• Self-hosted

Repro steps:

Add the following rule to labeler.yml:

SOMELABEL:
  - head-branch: '^(?i)(a).*'

Expected behavior:

The error shouldn't be thrown.

Actual behavior:

GitHub Actions runner on ubuntu-latest throw the following error:

The configuration file (path: .github/labeler.yml) was not found locally, fetching via the api
Error: SyntaxError: Invalid regular expression: /^(?i)(a).*/: Invalid group
Error: Invalid regular expression: /^(?i)(a).*/: Invalid group

[mahabaleshwars]

Hello @cjxe,
Thank you for creating this issue. We will investigate it and provide feedback as soon as we have some updates.

[suyashgaonkar]

Hi @cjxe , We did the initial investigation and it looks like the regex mentioned in the issue seems to be syntactically wrong, can you please help us to understand the use case of the regex or what exactly are you looking to achieve so that we could understand it better and come up with a solution.

[cjxe]

@suyashgaonkar - in this example, my aim was to match all the following strings:

• ads-0000
• Ads-0000
• aDs-0000
• ADs-0000
• adS-0000
• AdS-0000
• aDS-0000
• ADS-0000

So, I created this rule: "match the string that starts with a or A". See screenshot below:

[suyashgaonkar]

Hi @cjxe , Thank you for responding and providing us more details. As you have mentioned in the screenshot you have selected PCRE2 (regex flavour) to compile the mentioned regex code. (?i) modifier is not supported by all the regex flavours, actions/labelers uses javascript behind the scenes hence you would need to modify to something that would work on javascript flavour. We would recommend the following change :- “^(a|A).*” in the regex for the mentioned use case.
Kindly refer to following workflow run and labeler.yml config file for more details.