Fix to not link keg_only if it doesn't installed by request

[daeho-ro]

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From recent changes, installed_as_dependency value defaults to false and it is now changed to the reverse of installed_on_request. However, it's default value is also false and the test behavior is changed. I think the auto link guard should be kept and test should be fixed.

[Copilot]

Pull request overview

This PR changes FormulaInstaller so versioned keg-only formulae are only auto-linked, and only emit the manual-link warning, when they were installed on request. That aligns linking behavior with Homebrew's installed-on-request semantics for top-level installs versus dependency installs.

Changes:

• Add an installed_on_request? guard to auto_link_versioned_keg_only?.
• Add the same guard to link_manual_command_warning.
• Update formula_installer_spec.rb to cover the new default non-linking behavior for non-request installs and to keep the manual warning test on the request-install path.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
Library/Homebrew/formula_installer.rb	Gates versioned keg-only auto-linking and manual-link warnings on installed_on_request?.
Library/Homebrew/test/formula_installer_spec.rb	Adjusts installer specs for the new request-install behavior and updates one warning-path test.

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[MikeMcQuaid]

Thanks!

[daeho-ro]

One of docker step failed but it isn't related to the source changes.

[daeho-ro]

https://www.isitdownrightnow.com/launchpad.net.html 🥲

[daeho-ro]

This change is still not resolving the case that

• ghc@9.12 9.12.4 homebrew-core#279673

During ghc@9.12 version bump, haskell-language-server have both ghc and ghc@9.12. Unfortunately, in this case, ghc@9.12 is installed first and linked, and laster ghc is trying to install. At this moment, ghc cannot make link because of there is already link to keg_only and failed by lock status. (not sure this statement is correct but this is my best)

This is very unique case and not sure how to resolve.