Roll our own Gem#latest_load_paths and use it when Bundler not active

lib/spork.rb

@@ -11,6 +11,7 @@ module Spork
   autoload :Runner,        (LIBDIR + 'spork/runner').to_s
   autoload :Forker,        (LIBDIR + 'spork/forker').to_s
   autoload :Diagnoser,     (LIBDIR + 'spork/diagnoser').to_s
+  autoload :GemHelpers,    (LIBDIR + 'spork/gem_helpers').to_s
 
   class << self
     # Run a block, during prefork mode.  By default, if prefork is called twice in the same file and line number, the supplied block will only be ran once.
@@ -104,7 +105,7 @@ def detect_and_require(subfolder)
 
     # This method is used to auto-discover peer plugins such as spork-testunit.
     def other_spork_gem_load_paths
-      @other_spork_gem_load_paths ||= $LOAD_PATH.uniq.grep(/spork/).select do |g|
+      @other_spork_gem_load_paths ||= Spork::GemHelpers.latest_load_paths.grep(/spork/).select do |g|
         not g.match(%r{/spork-[0-9\-.]+/lib}) # don't include other versions of spork
       end
     end

lib/spork/gem_helpers.rb

@@ -0,0 +1,34 @@
+module Spork::GemHelpers
+  extend self
+
+  class GemPath
+    attr_reader :name, :version, :path, :version_numbers
+    include Comparable
+    def initialize(p)
+      @path = p
+      @name, @version = File.basename(p).scan(/^(.+?)-([^-]+)$/).flatten
+      @version_numbers = @version.split(/[^0-9]+/).map(&:to_i)
+    end
+
+    def <=>(other)
+      raise "Not comparable gem paths ('#{name}' is not '#{other.name}')" unless name == other.name
+      @version_numbers <=> other.version_numbers
+    end
+  end
+
+  def latest_load_paths
+    if defined?(Bundler)
+      $LOAD_PATH.uniq
+    else
+      Dir["{#{Gem.paths.path.join(',')}}" + "/gems/*"].inject({}) do |h,f|
+        gem_path = GemPath.new(f)
+        if h[gem_path.name]
+          h[gem_path.name] = gem_path if gem_path > h[gem_path.name]
+        else
+          h[gem_path.name] = gem_path
+        end
+        h
+      end
+    end
+  end
+end