3 files changed, 22 insertions, 5 deletions
diff --git a/lib/puppet/configurer.rb b/lib/puppet/configurer.rb
index 327955b03..31d31c2d2 100644
--- a/lib/puppet/configurer.rb
+++ b/lib/puppet/configurer.rb
@@ -158,6 +158,10 @@ class Puppet::Configurer
       return
     end
   ensure
+    # Make sure we forget the retained module_directories of any autoload
+    # we might have used.
+    Thread.current[:env_module_directories] = nil
+
     # Now close all of our existing http connections, since there's no
     # reason to leave them lying open.
     Puppet::Network::HttpPool.clear_http_instances
diff --git a/lib/puppet/parser/compiler.rb b/lib/puppet/parser/compiler.rb
index 61bb13cb6..98cad952c 100644
--- a/lib/puppet/parser/compiler.rb
+++ b/lib/puppet/parser/compiler.rb
@@ -23,6 +23,7 @@ class Puppet::Parser::Compiler
     # We get these from the environment and only cache them in a thread 
     # variable for the duration of the compilation.
     Thread.current[:known_resource_types] = nil
+    Thread.current[:env_module_directories] = nil
  end
 
   attr_reader :node, :facts, :collections, :catalog, :node_scope, :resources, :relationships
diff --git a/lib/puppet/util/autoload.rb b/lib/puppet/util/autoload.rb
index c293ac14a..f0dd0a5c5 100644
--- a/lib/puppet/util/autoload.rb
+++ b/lib/puppet/util/autoload.rb
@@ -131,11 +131,23 @@ class Puppet::Util::Autoload
     # We have to require this late in the process because otherwise we might have
     # load order issues.
     require 'puppet/node/environment'
-    Puppet::Node::Environment.new(env).modulepath.collect do |dir|
-      Dir.entries(dir).reject { |f| f =~ /^\./ }.collect { |f| File.join(dir, f) }
-    end.flatten.collect { |d| [File.join(d, "plugins"), File.join(d, "lib")] }.flatten.find_all do |d|
-      FileTest.directory?(d)
-    end
+
+    real_env = Puppet::Node::Environment.new(env)
+
+    # We're using a per-thread cache of said module directories, so that
+    # we don't scan the filesystem each time we try to load something with
+    # this autoload instance. But since we don't want to cache for the eternity
+    # this env_module_directories gets reset after the compilation on the master.
+    # This is also reset after an agent ran.
+    # One of the side effect of this change is that this module directories list will be
+    # shared among all autoload that we have running at a time. But that won't be an issue
+    # as by definition those directories are shared by all autoload.
+    Thread.current[:env_module_directories] ||= {}
+    Thread.current[:env_module_directories][real_env] ||= real_env.modulepath.collect do |dir|
+        Dir.entries(dir).reject { |f| f =~ /^\./ }.collect { |f| File.join(dir, f) }
+      end.flatten.collect { |d| [File.join(d, "plugins"), File.join(d, "lib")] }.flatten.find_all do |d|
+        FileTest.directory?(d)
+      end
   end
 
   def search_directories(env=nil)