doc: target_platforms

[aignas]

Followup to #3441 adding the documentation on how to use the new attribute.

Work towards #2949

[gemini-code-assist]

Summary of Changes

Hello @aignas, 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 enhances the documentation for rules_python by detailing the usage of the target_platforms attribute within pip.parse. It explains the default behavior regarding platform selection and provides guidance on how users can explicitly configure cross-platform building targets, addressing a follow-up from a previous feature introduction and working towards issue #2949.

Highlights

• Documentation for target_platforms: A new section has been added to docs/pypi/download.md to explain the target_platforms attribute for pip.parse.
• Cross-platform Building Clarification: The documentation now clarifies that rules_python defaults to the host platform and does not inherently provide cross-platform building support due to performance considerations related to wheel sizes and bazel query overhead.
• User Configuration Examples: Examples are provided to demonstrate how users can configure pip.parse.target_platforms to explicitly enable specific platform targets, such as free-threaded variants or different OS/architecture combinations.

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 adds documentation for the new target_platforms attribute in pip.parse. My review includes suggestions to improve the clarity and tone of the new documentation section, and a fix for an invalid code snippet to ensure the examples are correct and easy to understand.