extend/os/linux/linkage_checker: typed: strict

[cho-m]

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Part of #17297

Not sure if there is a better way to allow prepend-ed module to access instance variables without Sorbet complaining.

May be related to Sorbet's known limitations - https://sorbet.org/docs/unsupported#prepend

For now, using attr_reader and requires_ancestor to expose variables.

[Copilot]

Pull request overview

This PR upgrades the extend/os/linux/linkage_checker.rb file to use Sorbet's strict typing mode (typed: strict). To work around Sorbet's known limitations with prepended modules, the PR exposes instance variables through attr_reader methods and uses requires_ancestor to ensure type safety.

Key Changes

• Added proper type signatures and Sorbet helpers to the Linux-specific LinkageChecker module
• Exposed instance variables (indirect_deps, undeclared_deps, unwanted_system_dylibs, system_dylibs) as readable attributes in the base class
• Converted direct instance variable access to method calls in the Linux override

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
Library/Homebrew/linkage_checker.rb	Added attr_reader declarations for instance variables needed by the Linux-specific module, consolidated attribute declarations with proper type signatures
Library/Homebrew/extend/os/linux/linkage_checker.rb	Upgraded to typed: strict, added Sorbet helpers and requires_ancestor, added type annotations, and converted instance variable access to method calls

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[MikeMcQuaid]

Looks good, thanks!