From 099af8cf9cca19f6bfa3c4bd971f5a63661b37a8 Mon Sep 17 00:00:00 2001
From: Shaun Jackman <sjackman@gmail.com>
Date: Fri, 30 Oct 2020 10:40:10 -0700
Subject: [PATCH] Revert "Improve @-versioned formulae linking."

---
 Library/Homebrew/cmd/link.rb          | 24 ++++++++++-----------
 Library/Homebrew/cmd/switch.rb        |  3 ---
 Library/Homebrew/cmd/unlink.rb        |  7 +++++--
 Library/Homebrew/formula.rb           |  8 +++----
 Library/Homebrew/formula_installer.rb |  3 ---
 Library/Homebrew/keg.rb               |  2 --
 Library/Homebrew/unlink.rb            | 30 ---------------------------
 docs/Manpage.md                       |  4 ++++
 manpages/brew.1                       |  3 +++
 9 files changed, 27 insertions(+), 57 deletions(-)
 delete mode 100644 Library/Homebrew/unlink.rb

diff --git a/Library/Homebrew/cmd/link.rb b/Library/Homebrew/cmd/link.rb
index f84fa9411d..ad48c17792 100644
--- a/Library/Homebrew/cmd/link.rb
+++ b/Library/Homebrew/cmd/link.rb
@@ -4,7 +4,6 @@
 require "ostruct"
 require "caveats"
 require "cli/parser"
-require "unlink"
 
 module Homebrew
   module_function
@@ -67,27 +66,26 @@ module Homebrew
         next
       end
 
-      formula = keg.to_formula
-
       if keg_only
-        if Homebrew.default_prefix? && formula.keg_only_reason.by_macos?
-          caveats = Caveats.new(formula)
-          opoo <<~EOS
-            Refusing to link macOS provided/shadowed software: #{keg.name}
-            #{caveats.keg_only_text(skip_reason: true).strip}
-          EOS
-          next
+        if Homebrew.default_prefix?
+          f = keg.to_formula
+          if f.keg_only_reason.by_macos?
+            caveats = Caveats.new(f)
+            opoo <<~EOS
+              Refusing to link macOS provided/shadowed software: #{keg.name}
+              #{caveats.keg_only_text(skip_reason: true).strip}
+            EOS
+            next
+          end
         end
 
-        if !formula.keg_only_reason.versioned_formula? && !args.force?
+        unless args.force?
           opoo "#{keg.name} is keg-only and must be linked with --force"
           puts_keg_only_path_message(keg)
           next
         end
       end
 
-      Unlink.unlink_versioned_formulae(formula, verbose: args.verbose?)
-
       keg.lock do
         print "Linking #{keg}... "
         puts if args.verbose?
diff --git a/Library/Homebrew/cmd/switch.rb b/Library/Homebrew/cmd/switch.rb
index 0877f51d09..94389f2b8e 100644
--- a/Library/Homebrew/cmd/switch.rb
+++ b/Library/Homebrew/cmd/switch.rb
@@ -17,7 +17,6 @@ module Homebrew
       EOS
 
       named 2
-      hide_from_man_page!
     end
   end
 
@@ -29,8 +28,6 @@ module Homebrew
 
     odie "#{name} not found in the Cellar." unless rack.directory?
 
-    # odeprecated "`brew switch`", "`brew link` @-versioned formulae"
-
     versions = rack.subdirs
                    .map { |d| Keg.new(d).version }
                    .sort
diff --git a/Library/Homebrew/cmd/unlink.rb b/Library/Homebrew/cmd/unlink.rb
index 2abbc3d947..080bcd1636 100644
--- a/Library/Homebrew/cmd/unlink.rb
+++ b/Library/Homebrew/cmd/unlink.rb
@@ -3,7 +3,6 @@
 
 require "ostruct"
 require "cli/parser"
-require "unlink"
 
 module Homebrew
   module_function
@@ -37,7 +36,11 @@ module Homebrew
         next
       end
 
-      Unlink.unlink(keg, dry_run: args.dry_run?, verbose: args.verbose?)
+      keg.lock do
+        print "Unlinking #{keg}... "
+        puts if args.verbose?
+        puts "#{keg.unlink(**options)} symlinks removed"
+      end
     end
   end
 end
diff --git a/Library/Homebrew/formula.rb b/Library/Homebrew/formula.rb
index 5dd79b65dd..6812b905f4 100644
--- a/Library/Homebrew/formula.rb
+++ b/Library/Homebrew/formula.rb
@@ -414,12 +414,12 @@ class Formula
     name.include?("@")
   end
 
-  # Returns any `@`-versioned formulae for any formula (including versioned formulae).
+  # Returns any `@`-versioned formulae for an non-`@`-versioned formula.
   def versioned_formulae
-    Pathname.glob(path.to_s.gsub(/(@[\d.]+)?\.rb$/, "@*.rb")).map do |versioned_path|
-      next if versioned_path == path
+    return [] if versioned_formula?
 
-      Formula[versioned_path.basename(".rb").to_s]
+    Pathname.glob(path.to_s.gsub(/\.rb$/, "@*.rb")).map do |path|
+      Formula[path.basename(".rb").to_s]
     rescue FormulaUnavailableError
       nil
     end.compact.sort_by(&:version).reverse
diff --git a/Library/Homebrew/formula_installer.rb b/Library/Homebrew/formula_installer.rb
index 57aedf4434..c9a29c3315 100644
--- a/Library/Homebrew/formula_installer.rb
+++ b/Library/Homebrew/formula_installer.rb
@@ -22,7 +22,6 @@ require "cmd/install"
 require "find"
 require "utils/spdx"
 require "deprecate_disable"
-require "unlink"
 
 # Installer for a formula.
 #
@@ -885,8 +884,6 @@ class FormulaInstaller
       keg.remove_linked_keg_record
     end
 
-    Homebrew::Unlink.unlink_versioned_formulae(formula, verbose: verbose?)
-
     link_overwrite_backup = {} # Hash: conflict file -> backup file
     backup_dir = HOMEBREW_CACHE/"Backup"
 
diff --git a/Library/Homebrew/keg.rb b/Library/Homebrew/keg.rb
index a06ac9617f..902ed12f38 100644
--- a/Library/Homebrew/keg.rb
+++ b/Library/Homebrew/keg.rb
@@ -335,7 +335,6 @@ class Keg
     EOS
   end
 
-  # TODO: refactor to use keyword arguments.
   def unlink(**options)
     ObserverPathnameExtension.reset_counts!
 
@@ -449,7 +448,6 @@ class Keg
     end
   end
 
-  # TODO: refactor to use keyword arguments.
   def link(**options)
     raise AlreadyLinkedError, self if linked_keg_record.directory?
 
diff --git a/Library/Homebrew/unlink.rb b/Library/Homebrew/unlink.rb
deleted file mode 100644
index bd265d5c5c..0000000000
--- a/Library/Homebrew/unlink.rb
+++ /dev/null
@@ -1,30 +0,0 @@
-# typed: false
-# frozen_string_literal: true
-
-module Homebrew
-  # Provides helper methods for unlinking formulae and kegs with consistent output.
-  module Unlink
-    module_function
-
-    def unlink_versioned_formulae(formula, verbose: false)
-      formula.versioned_formulae
-             .select(&:linked?)
-             .map(&:any_installed_keg)
-             .compact
-             .select(&:directory?)
-             .each do |keg|
-        unlink(keg, verbose: verbose)
-      end
-    end
-
-    def unlink(keg, dry_run: false, verbose: false)
-      options = { dry_run: dry_run, verbose: verbose }
-
-      keg.lock do
-        print "Unlinking #{keg}... "
-        puts if verbose
-        puts "#{keg.unlink(**options)} symlinks removed"
-      end
-    end
-  end
-end
diff --git a/docs/Manpage.md b/docs/Manpage.md
index f6f194eb7d..d3cbe3eeb5 100644
--- a/docs/Manpage.md
+++ b/docs/Manpage.md
@@ -537,6 +537,10 @@ Print export statements. When run in a shell, this installation of Homebrew will
 The variables `HOMEBREW_PREFIX`, `HOMEBREW_CELLAR` and `HOMEBREW_REPOSITORY` are also exported to avoid querying them multiple times.
 Consider adding evaluation of this command's output to your dotfiles (e.g. `~/.profile`, `~/.bash_profile`, or `~/.zprofile`) with: `eval $(brew shellenv)`
 
+### `switch` *`formula`* *`version`*
+
+Symlink all of the specified *`version`* of *`formula`*'s installation into Homebrew's prefix.
+
 ### `tap` [*`options`*] [*`user`*`/`*`repo`*] [*`URL`*]
 
 Tap a formula repository.
diff --git a/manpages/brew.1 b/manpages/brew.1
index dd87f709ac..394ee5589f 100644
--- a/manpages/brew.1
+++ b/manpages/brew.1
@@ -773,6 +773,9 @@ Print export statements\. When run in a shell, this installation of Homebrew wil
 .P
 The variables \fBHOMEBREW_PREFIX\fR, \fBHOMEBREW_CELLAR\fR and \fBHOMEBREW_REPOSITORY\fR are also exported to avoid querying them multiple times\. Consider adding evaluation of this command\'s output to your dotfiles (e\.g\. \fB~/\.profile\fR, \fB~/\.bash_profile\fR, or \fB~/\.zprofile\fR) with: \fBeval $(brew shellenv)\fR
 .
+.SS "\fBswitch\fR \fIformula\fR \fIversion\fR"
+Symlink all of the specified \fIversion\fR of \fIformula\fR\'s installation into Homebrew\'s prefix\.
+.
 .SS "\fBtap\fR [\fIoptions\fR] [\fIuser\fR\fB/\fR\fIrepo\fR] [\fIURL\fR]"
 Tap a formula repository\.
 .