autoremove.rb: moved logic out into formula.rb, and uninstall.rb

This allows us to autoremove formulae in the autoremove and
uninstall commands without having to shell out to brew.

Library/Homebrew/cmd/autoremove.rb

@@ -20,37 +20,9 @@ module Homebrew
     end
   end
 
-  def get_removable_formulae(formulae)
-    removable_formulae = Formula.installed_formulae_with_no_dependents(formulae).reject do |f|
-      Tab.for_keg(f.any_installed_keg).installed_on_request
-    end
-
-    removable_formulae += get_removable_formulae(formulae - removable_formulae) if removable_formulae.present?
-
-    removable_formulae
-  end
-
   def autoremove
     args = autoremove_args.parse
 
-    removable_formulae = get_removable_formulae(Formula.installed)
+    Uninstall.autoremove_kegs(Formula.removable_formulae, dry_run: args.dry_run?)
-
-    if (casks = Cask::Caskroom.casks.presence)
-      removable_formulae -= casks.flat_map { |cask| cask.depends_on[:formula] }
-                                 .compact
-                                 .map { |f| Formula[f] }
-                                 .flat_map { |f| [f, *f.runtime_formula_dependencies].compact }
-    end
-    return if removable_formulae.blank?
-
-    formulae_names = removable_formulae.map(&:full_name).sort
-
-    verb = args.dry_run? ? "Would uninstall" : "Uninstalling"
-    oh1 "#{verb} #{formulae_names.count} unneeded #{"formula".pluralize(formulae_names.count)}:"
-    puts formulae_names.join("\n")
-    return if args.dry_run?
-
-    kegs_by_rack = removable_formulae.map(&:any_installed_keg).group_by(&:rack)
-    Uninstall.uninstall_kegs(kegs_by_rack)
   end
 end

Library/Homebrew/cmd/uninstall.rb

@@ -81,6 +81,6 @@ module Homebrew
 
     return unless Homebrew::EnvConfig.uninstall_autoremove?
 
-    system HOMEBREW_BREW_FILE, "autoremove"
+    Uninstall.autoremove_kegs(Formula.removable_formulae)
   end
 end

Library/Homebrew/formula.rb

@@ -1706,7 +1706,7 @@ class Formula
     end.uniq(&:name)
   end
 
-  # An array of all installed {Formula} without dependents
+  # An array of all installed {Formula} without {Formula} dependents
   # @private
   def self.installed_formulae_with_no_dependents(formulae = installed)
     return [] if formulae.blank?
@@ -1720,6 +1720,37 @@ class Formula
     installed.select { |f| f.installed_alias_path == alias_path }
   end
 
+  # An array of all installed {Formula} with {Cask} dependents.
+  # @private
+  def self.installed_formulae_with_cask_dependents
+    Cask::Caskroom.casks
+                  .flat_map { |cask| cask.depends_on[:formula] }
+                  .compact
+                  .map { |f| Formula[f] }
+                  .flat_map { |f| [f, *f.runtime_formula_dependencies].compact }
+  end
+
+  # An array of all installed {Formula} without {Formula} or {Cask} dependents
+  # that weren't installed on request.
+  # @private
+  def self.removable_formulae
+    formulae = installed
+    all_removable_formulae = T.let([], T::Array[Formula])
+
+    loop do
+      removable_formulae = installed_formulae_with_no_dependents(formulae).reject do |f|
+        Tab.for_keg(f.any_installed_keg).installed_on_request
+      end
+
+      break if removable_formulae.blank?
+
+      all_removable_formulae += removable_formulae
+      formulae -= removable_formulae
+    end
+
+    all_removable_formulae - installed_formulae_with_cask_dependents
+  end
+
   # an array of all alias files of core {Formula}
   # @private
   def self.core_alias_files

Library/Homebrew/uninstall.rb

@@ -97,6 +97,20 @@ module Homebrew
       end
     end
 
+    def autoremove_kegs(removable_formulae, dry_run: false)
+      return if removable_formulae.blank?
+
+      formulae_names = removable_formulae.map(&:full_name).sort
+
+      verb = dry_run ? "Would uninstall" : "Uninstalling"
+      oh1 "#{verb} #{formulae_names.count} unneeded #{"formula".pluralize(formulae_names.count)}:"
+      puts formulae_names.join("\n")
+      return if dry_run
+
+      kegs_by_rack = removable_formulae.map(&:any_installed_keg).group_by(&:rack)
+      Uninstall.uninstall_kegs(kegs_by_rack)
+    end
+
     def handle_unsatisfied_dependents(kegs_by_rack, casks: [], ignore_dependencies: false, named_args: [])
       return if ignore_dependencies