Bug: Cask artifact stanza fails on Linux after bd4eb5ed - Sorbet type mismatch in add_altname_metadata

[bogdan-d]

Bug Description

After commit bd4eb5edc679f3c444e43e36784febcb6cb28af5 ("Only use MachOShim/ELFShim when required", Nov 29 2025), installing casks that use the artifact stanza on Linux fails with a Sorbet type validation error.

Error Message

Error: Parameter 'file': Expected type OS::Linux::Pathname, got type Pathname with value #<Pathname:/home/user/.local/share/applications/example.desktop>
Caller: .../cask/artifact/moved.rb:134
Definition: .../extend/os/linux/cask/artifact/relocated.rb:14 (OS::Linux::Cask::Artifact::Relocated#add_altname_metadata)

Root Cause

The commit changed how ELFShim is applied to Pathname on Linux for performance reasons:

Before:

class Pathname
  prepend ELFShim
end

After:

module OS::Linux::Pathname::ClassMethods
  def activate_extensions!
    super
    prepend(ELFShim)
  end
end

This means some Pathname objects now have ELFShim mixed in (becoming OS::Linux::Pathname) while others don't. When post_move in moved.rb:134 calls add_altname_metadata(target, source.basename, command:), there's a type mismatch between what Sorbet expects and what's actually passed.

The type signature in extend/os/linux/cask/artifact/relocated.rb declares:

sig { params(file: Pathname, altname: Pathname, command: T.class_of(SystemCommand)).returns(T.nilable(SystemCommand::Result)) }

But the actual target variable being passed is a different Pathname variant.

Steps to Reproduce

1. Use Homebrew on Linux (Linuxbrew)
2. Create/install a cask with an artifact stanza targeting a user directory:

   artifact "source.desktop", target: "\#{Dir.home}/.local/share/applications/target.desktop"

3. Run: brew install --cask <cask_name>
4. Installation fails with the Sorbet type mismatch error

Expected Behavior

The artifact stanza should work correctly on Linux without type validation errors.

System Information

Homebrew 5.0.3-62-ga766abe
Linux (Linuxbrew)

Workaround

Cask authors can replace the artifact stanza with manual file copy operations in preflight/uninstall_preflight blocks.

Related

• Commit: bd4eb5e
• PR: Only use MachOShim/ELFShim when required #21071