diff --git a/lib/puma.rb b/lib/puma.rb
index cdbefef870..497e22f1a5 100644
--- a/lib/puma.rb
+++ b/lib/puma.rb
@@ -19,6 +19,24 @@ module Puma
   autoload :Server, 'puma/server'
   autoload :Launcher, 'puma/launcher'
 
+  # at present, MiniSSL::Engine is only defined in extension code (puma_http11),
+  # not in minissl.rb
+  HAS_SSL = const_defined?(:MiniSSL, false) && MiniSSL.const_defined?(:Engine, false)
+
+  if HAS_SSL
+    require 'puma/minissl'
+  else
+    module MiniSSL
+      # this class is defined so that it exists when Puma is compiled
+      # without ssl support, as Server and Reactor use it in rescue statements.
+      class SSLError < StandardError ; end
+    end
+  end
+
+  def self.ssl?
+    HAS_SSL
+  end
+
   # @!attribute [rw] stats_object=
   def self.stats_object=(val)
     @get_stats = val
@@ -40,12 +58,4 @@ def self.set_thread_name(name)
     return unless Thread.current.respond_to?(:name=)
     Thread.current.name = "puma #{name}"
   end
-
-  unless HAS_SSL
-    module MiniSSL
-      # this class is defined so that it exists when Puma is compiled
-      # without ssl support, as Server and Reactor use it in rescue statements.
-      class SSLError < StandardError ; end
-    end
-  end
 end
diff --git a/lib/puma/detect.rb b/lib/puma/detect.rb
index 05d5384f16..c85a359704 100644
--- a/lib/puma/detect.rb
+++ b/lib/puma/detect.rb
@@ -1,32 +1,36 @@
 # frozen_string_literal: true
 
+# This file can be loaded independently of puma.rb, so it cannot have any code
+# that assumes puma.rb is loaded.
+
+
 module Puma
-  # at present, MiniSSL::Engine is only defined in extension code, not in minissl.rb
-  HAS_SSL = const_defined?(:MiniSSL, false) && MiniSSL.const_defined?(:Engine, false)
+  # @version 5.2.1
+  HAS_FORK = ::Process.respond_to? :fork
 
-  def self.ssl?
-    HAS_SSL
-  end
+  IS_JRUBY = Object.const_defined? :JRUBY_VERSION
 
-  IS_JRUBY = defined?(JRUBY_VERSION)
+  IS_WINDOWS = !!(RUBY_PLATFORM =~ /mswin|ming|cygwin/ ||
+    IS_JRUBY && RUBY_DESCRIPTION =~ /mswin/)
+
+  # @version 5.2.0
+  IS_MRI = (RUBY_ENGINE == 'ruby' || RUBY_ENGINE.nil?)
 
   def self.jruby?
     IS_JRUBY
   end
 
-  IS_WINDOWS = RUBY_PLATFORM =~ /mswin|ming|cygwin/
-
   def self.windows?
     IS_WINDOWS
   end
 
   # @version 5.0.0
   def self.mri?
-    RUBY_ENGINE == 'ruby' || RUBY_ENGINE.nil?
+    IS_MRI
   end
 
   # @version 5.0.0
   def self.forkable?
-    ::Process.respond_to?(:fork)
+    HAS_FORK
   end
 end