Improve grepping

[hahwul]

ref from #883

[gemini-code-assist]

Summary of Changes

Hello @hahwul, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request significantly enhances the robustness and accuracy of the grepping functionality. It introduces error handling for regular expression compilation, ensuring that the application can gracefully manage malformed patterns. Additionally, it refines several predefined regular expressions to improve their precision in identifying specific patterns, which helps in reducing false positives and negatives during scanning operations.

Highlights

• Improved Regex Error Handling: The Grepping function now gracefully handles invalid regular expressions by catching errors from regexp.Compile and returning an empty slice, preventing application panics.
• Enhanced Regex Accuracy: Several built-in regular expressions have been refined to improve their accuracy. This includes escaping literal dot characters (.) that were previously interpreted as wildcards and adding word boundaries (\b) for more precise matching of tokens.
• Comprehensive Test Coverage: New unit tests have been added to validate the improved regex error handling and to thoroughly test the corrected built-in patterns, ensuring their intended behavior and precision.

🧠 New Feature in Public Preview: You can now enable Memory to help Gemini Code Assist learn from your team's feedback. This makes future code reviews more consistent and personalized to your project's style. Click here to enable Memory in your admin console.

Using Gemini Code Assist

The full guide for Gemini Code Assist can be found on our documentation page, here are some quick tips.

Invoking Gemini

You can request assistance from Gemini at any point by creating a comment using either /gemini <command> or @gemini-code-assist <command>. Below is a summary of the supported commands on the current page.

Feature	Command	Description
Code Review	/gemini review	Performs a code review for the current pull request in its current state.
Pull Request Summary	/gemini summary	Provides a summary of the current pull request in its current state.
Comment	@gemini-code-assist	Responds in comments when explicitly tagged, both in pull request comments and review comments.
Help	/gemini help	Displays a list of available commands.

Customization

To customize Gemini Code Assist for GitHub experience, repository maintainers can create a configuration file and/or provide a custom code review style guide (such as PEP-8 for Python) by creating and adding files to a .gemini/ folder in the base of the repository. Detailed instructions can be found here.

Limitations & Feedback

Gemini Code Assist may make mistakes. Please leave feedback on any instances where its feedback is incorrect or counter productive. You can react with 👍 and 👎 on @gemini-code-assist comments. If you're interested in giving your feedback about your experience with Gemini Code Assist for Github and other Google products, sign up here.

You can also get AI-powered code generation, chat, as well as code reviews directly in the IDE at no cost with the Gemini Code Assist IDE Extension.

Footnotes

1. Review the Privacy Notices, Generative AI Prohibited Use Policy, Terms of Service, and learn how to configure Gemini Code Assist in GitHub here. Gemini can make mistakes, so double check it and use code with caution. ↩

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

📢 Thoughts on this report? Let us know!

[gemini-code-assist]

Code Review

This pull request brings significant improvements to the grepping functionality. The change to handle regex compilation errors gracefully prevents potential panics, making the code more robust. Numerous regular expressions have been corrected, fixing invalid patterns and improving the precision of others to reduce false positives. Furthermore, the test suite has been substantially enhanced, particularly with the refactoring of TestBuiltinGrep, which is now much cleaner, more comprehensive, and easier to maintain. Overall, this is an excellent set of changes that improves code quality, correctness, and testability.