Use a command registry

Library/Homebrew/abstract_command.rb

@@ -1,6 +1,8 @@
 # typed: strong
 # frozen_string_literal: true
 
+require "command_registry"
+
 module Homebrew
   class AbstractCommand
     extend T::Helpers
@@ -12,13 +14,9 @@ module Homebrew
       sig { params(subclass: T.class_of(AbstractCommand)).void }
       def inherited(subclass)
         super
-        @cmds ||= T.let({}, T.nilable(T::Hash[String, T.class_of(AbstractCommand)]))
-        @cmds[subclass.command_name] = subclass
+        CommandRegistry.register(subclass)
       end
 
-      sig { params(name: String).returns(T.nilable(T.class_of(AbstractCommand))) }
-      def command(name) = @cmds&.[](name)
-
       sig { returns(String) }
       def command_name = T.must(name).split("::").fetch(-1).downcase
     end

Library/Homebrew/brew.rb

@@ -84,7 +84,7 @@ begin
   end
 
   if internal_cmd || Commands.external_ruby_v2_cmd_path(cmd)
-    cmd_class = Homebrew::AbstractCommand.command(T.must(cmd))
+    cmd_class = Homebrew::CommandRegistry.command(T.must(cmd))
     if cmd_class
       cmd_class.new.run
     else

Library/Homebrew/command_registry.rb

@@ -0,0 +1,19 @@
+# typed: strong
+# frozen_string_literal: true
+
+module Homebrew
+  module CommandRegistry
+    extend T::Helpers
+
+    Cmd = T.type_alias { T.class_of(AbstractCommand) } # rubocop:disable Style/MutableConstant
+
+    sig { params(subclass: Cmd).void }
+    def self.register(subclass)
+      @cmds ||= T.let({}, T.nilable(T::Hash[String, Cmd]))
+      @cmds[subclass.command_name] = subclass
+    end
+
+    sig { params(name: String).returns(T.nilable(Cmd)) }
+    def self.command(name) = @cmds&.[](name)
+  end
+end