fix(types): package.loadlib return nil, err when fail

[phanen]

No description provided.

[gemini-code-assist]

Summary of Changes

Hello @phanen, 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 refines the type definition within the emmylua_code_analysis project by correcting the return type annotation for the package.loadlib function. The change ensures that the type information precisely indicates that the function can return a loaded function or a string containing an error message, thereby enhancing the accuracy of static analysis and type checking for Lua code.

Highlights

• Type Definition Correction: The return type annotation for the package.loadlib function has been updated to accurately reflect its behavior of returning either a function or an error string upon failure.

🧠 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. ↩

[gemini-code-assist]

Code Review

This pull request corrects the return type annotation for package.loadlib in the standard library definitions. The original annotation was incorrect. Your change is a good fix, but I've provided a suggestion to make the type even more accurate by considering the behavior of package.loadlib in different Lua versions (5.1 vs 5.2+), where it can return a different number of error messages on failure.

[gemini-code-assist]

While this is a great improvement over the previous incorrect type, to be more precise, package.loadlib can return two error strings on failure in Lua 5.2 and later versions. On Lua 5.1, it returns one error string. To correctly type this for all versions, you can specify three optional return values. When fewer values are returned, the remaining ones will be nil, which matches the string? type.

This would make the type hint more accurate for users on modern Lua versions.

---@return function?, string?, string?