Fix keg relocation for Homebrew-created files to ensure proper bottling

[Copilot]

This PR fixes an issue where Homebrew-created files (such as service definition files) were not being properly relocated when using the new /usr/local relocation logic on Intel macOS systems. This was causing bottle creation failures for formulae that generate service files containing generic paths like /usr/local/bin.

Problem

The current keg relocation logic uses selective path replacement when HOMEBREW_PREFIX=/usr/local to avoid overzealous replacement of system paths. However, this meant that Homebrew-generated service files containing paths like:

ExecStart=/usr/local/bin/some-command
Environment="PATH=/usr/local/sbin:/usr/sbin:/usr/bin:/bin:/usr/local/bin"
WorkingDirectory=/usr/local/var/something

Were not getting their /usr/local paths replaced with @@HOMEBREW_PREFIX@@ placeholders, making bottles non-relocatable.

Solution

The fix introduces minimal logic to identify Homebrew-created files and apply full path relocation to them:

1. File Detection: Added homebrew_created_file?() method that identifies service files (.plist, .service, .timer) with names starting with "homebrew."

2. Inline Relocation Logic: Modified existing replace_text_in_files() method to use full prefix replacement for Homebrew-created files when using selective relocation, avoiding code duplication

3. Conditional Processing: Only applies full relocation to Homebrew files when new_usr_local_relocation? is true, maintaining selective relocation for regular files

Result

Service files now get properly relocated:

ExecStart=@@HOMEBREW_PREFIX@@/bin/some-command
Environment="PATH=@@HOMEBREW_PREFIX@@/sbin:/usr/sbin:/usr/bin:/bin:@@HOMEBREW_PREFIX@@/bin"
WorkingDirectory=@@HOMEBREW_PREFIX@@/var/something

This ensures bottles can be successfully created and relocated between different Homebrew installations without breaking service functionality.

The implementation follows DRY and YAGNI principles with minimal code changes (21 lines added) by reusing existing relocation logic rather than duplicating it.

Fixes #20627.

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[MikeMcQuaid]

@copilot The approach is sensible but you've added far, far more code than is necessary. Simplify things: DRY, YAGNI, etc. Try to make the bare minimum number of changes in order to achieve the result. The fewer lines in the diff: the better.

[Copilot]

@copilot The approach is sensible but you've added far, far more code than is necessary. Simplify things: DRY, YAGNI, etc. Try to make the bare minimum number of changes in order to achieve the result...

Simplified the approach to use DRY and YAGNI principles. Reduced the diff from 198 lines to 44 lines by:

1. Reusing existing relocation logic instead of duplicating it
2. Adding minimal homebrew_created_file? helper method
3. Modifying existing replace_text_in_files method to handle homebrew files inline
4. Moving tests to keg_spec.rb instead of separate file

Commit: ac2d888

[MikeMcQuaid]

@copilot Still far too much new logic here. Trim it down a lot. Throw away all existing logic and start again.

[Copilot]

@copilot Still far too much new logic here. Trim it down a lot. Throw away all existing logic and start again.

Threw away the existing logic and implemented a much simpler approach. Reduced from 198 lines to just 21 lines of changes by adding a minimal helper method and modifying the existing replace_text_in_files method inline. Commit: 9be4ca2

[Rylan12]

Makes sense!