move deprecated codes into compat

Closes Homebrew/homebrew#41974.

Library/Homebrew/compat.rb

@@ -6,3 +6,4 @@ require 'compat/macos'
 require 'compat/md5'
 require 'compat/requirements'
 require 'compat/version'
+require 'compat/download_strategy'

Library/Homebrew/compat/download_strategy.rb

@@ -0,0 +1,6 @@
+require "download_strategy"
+
+CurlSSL3DownloadStrategy = CurlDownloadStrategy
+CurlUnsafeDownloadStrategy = CurlDownloadStrategy
+StrictSubversionDownloadStrategy = SubversionDownloadStrategy
+UnsafeSubversionDownloadStrategy = SubversionDownloadStrategy

Library/Homebrew/compat/formula.rb

@@ -43,4 +43,20 @@ class Formula
   def self.require_universal_deps
     define_method(:require_universal_deps?) { true }
   end
+
+  def self.path name
+    Formulary.core_path(name)
+  end
+
+  DATA = :DATA
+
+  def patches; {} end
+
+  def python(options={}, &block)
+    opoo 'Formula#python is deprecated and will go away shortly.'
+    block.call if block_given?
+    PythonRequirement.new
+  end
+  alias_method :python2, :python
+  alias_method :python3, :python
 end

Library/Homebrew/download_strategy.rb

@@ -397,9 +397,6 @@ class CurlPostDownloadStrategy < CurlDownloadStrategy
   end
 end
 
-# @deprecated
-CurlSSL3DownloadStrategy = CurlDownloadStrategy
-
 # Use this strategy to download but not unzip a file.
 # Useful for installing jars.
 class NoUnzipCurlDownloadStrategy < CurlDownloadStrategy
@@ -408,9 +405,6 @@ class NoUnzipCurlDownloadStrategy < CurlDownloadStrategy
   end
 end
 
-# @deprecated
-CurlUnsafeDownloadStrategy = CurlDownloadStrategy
-
 # This strategy extracts our binary packages.
 class CurlBottleDownloadStrategy < CurlDownloadStrategy
   def stage
@@ -538,11 +532,6 @@ class SubversionDownloadStrategy < VCSDownloadStrategy
   alias_method :update, :clone_repo
 end
 
-# @deprecated
-StrictSubversionDownloadStrategy = SubversionDownloadStrategy
-# @deprecated
-UnsafeSubversionDownloadStrategy = SubversionDownloadStrategy
-
 class GitDownloadStrategy < VCSDownloadStrategy
   SHALLOW_CLONE_WHITELIST = [
     %r{git://},

Library/Homebrew/formula.rb

@@ -261,7 +261,7 @@ class Formula
     (dir = installed_prefix).directory? && dir.children.length > 0
   end
 
-  # @deprecated
+  # @private
   # The `LinkedKegs` directory for this {Formula}.
   # You probably want {#opt_prefix} instead.
   def linked_keg
@@ -494,12 +494,6 @@ class Formula
   # tell the user about any caveats regarding this package, return a string
   def caveats; nil end
 
-  # @deprecated
-  DATA = :DATA
-
-  # @deprecated
-  def patches; {} end
-
   # rarely, you don't want your library symlinked into the main prefix
   # see gettext.rb for an example
   def keg_only?
@@ -627,15 +621,6 @@ class Formula
     ]
   end
 
-  # @deprecated
-  def python(options={}, &block)
-    opoo 'Formula#python is deprecated and will go away shortly.'
-    block.call if block_given?
-    PythonRequirement.new
-  end
-  alias_method :python2, :python
-  alias_method :python3, :python
-
   # an array of all core {Formula} names
   def self.core_names
     @core_names ||= Dir["#{HOMEBREW_LIBRARY}/Formula/*.rb"].map{ |f| File.basename f, ".rb" }.sort
@@ -715,11 +700,6 @@ class Formula
     path == Formulary.core_path(name)
   end
 
-  # @deprecated
-  def self.path name
-    Formulary.core_path(name)
-  end
-
   def env
     self.class.env
   end