Use the central priority map for `provides`

15 files changed, 366 insertions, 129 deletions

diff --git a/lib/chef/chef_class.rb b/lib/chef/chef_class.rb
index d3f7ee55c7..96c0899d5d 100644
--- a/lib/chef/chef_class.rb
+++ b/lib/chef/chef_class.rb
@@ -26,6 +26,9 @@
 # injected" into this class by other objects and do not reference the class symbols in those files
 # directly and we do not need to require those files here.
 
+require 'chef/platform/provider_priority_map'
+require 'chef/platform/resource_priority_map'
+
 class Chef
   class << self
 
@@ -48,7 +51,7 @@ class Chef
     # @param resource_name [Symbol] name of the resource as a symbol
     # @return [Array<Class>] Priority Array of Provider Classes to use for the resource_name on the node
     def get_provider_priority_array(resource_name)
-      @provider_priority_map.get_priority_array(node, resource_name).dup
+      provider_priority_map.get_priority_array(node, resource_name).dup
     end
 
     # Get the array of resources associated with a resource_name for the current node
@@ -56,27 +59,27 @@ class Chef
     # @param resource_name [Symbol] name of the resource as a symbol
     # @return [Array<Class>] Priority Array of Resource Classes to use for the resource_name on the node
     def get_resource_priority_array(resource_name)
-      @resource_priority_map.get_priority_array(node, resource_name).dup
+      resource_priority_map.get_priority_array(node, resource_name).dup
     end
 
     # Set the array of providers associated with a resource_name for the current node
     #
     # @param resource_name [Symbol] name of the resource as a symbol
-    # @param priority_array [Array<Class>] Array of Classes to set as the priority for resource_name on the node
+    # @param priority_array [Class, Array<Class>] Class or Array of Classes to set as the priority for resource_name on the node
     # @param filter [Hash] Chef::Nodearray-style filter
     # @return [Array<Class>] Modified Priority Array of Provider Classes to use for the resource_name on the node
     def set_provider_priority_array(resource_name, priority_array, *filter)
-      @provider_priority_map.set_priority_array(resource_name, priority_array, *filter).dup
+      provider_priority_map.set_priority_array(resource_name, priority_array, *filter).dup
     end
 
     # Get the array of resources associated with a resource_name for the current node
     #
     # @param resource_name [Symbol] name of the resource as a symbol
-    # @param priority_array [Array<Class>] Array of Classes to set as the priority for resource_name on the node
+    # @param priority_array [Class, Array<Class>] Class or Array of Classes to set as the priority for resource_name on the node
     # @param filter [Hash] Chef::Nodearray-style filter
     # @return [Array<Class>] Modified Priority Array of Resource Classes to use for the resource_name on the node
     def set_resource_priority_array(resource_name, priority_array, *filter)
-      @resource_priority_map.set_priority_array(resource_name, priority_array, *filter).dup
+      resource_priority_map.set_priority_array(resource_name, priority_array, *filter).dup
     end
 
     #
@@ -126,5 +129,23 @@ class Chef
       @provider_priority_map = nil
       @resource_priority_map = nil
     end
+
+    private
+
+    def provider_priority_map
+      @provider_priority_map ||= begin
+        # these slurp in the resource+provider world, so be exceedingly lazy about requiring them
+        require 'chef/platform/provider_priority_map'
+        Chef::Platform::ProviderPriorityMap.instance
+      end
+    end
+    def resource_priority_map
+      @resource_priority_map ||= begin
+        require 'chef/platform/resource_priority_map'
+        Chef::Platform::ResourcePriorityMap.instance
+      end
+    end
   end
+
+  reset!
 end
diff --git a/lib/chef/client.rb b/lib/chef/client.rb
index 141827e65b..86e92585e3 100644
--- a/lib/chef/client.rb
+++ b/lib/chef/client.rb
@@ -159,13 +159,6 @@ class Chef
       if new_runlist = args.delete(:runlist)
         @json_attribs["run_list"] = new_runlist
       end
-
-      # these slurp in the resource+provider world, so be exceedingly lazy about requiring them
-      require 'chef/platform/provider_priority_map' unless defined? Chef::Platform::ProviderPriorityMap
-      require 'chef/platform/resource_priority_map' unless defined? Chef::Platform::ResourcePriorityMap
-
-      Chef.set_provider_priority_map(Chef::Platform::ProviderPriorityMap.instance)
-      Chef.set_resource_priority_map(Chef::Platform::ResourcePriorityMap.instance)
     end
 
     #
diff --git a/lib/chef/mixin/provides.rb b/lib/chef/mixin/provides.rb
index c39c53a190..c95cb753a8 100644
--- a/lib/chef/mixin/provides.rb
+++ b/lib/chef/mixin/provides.rb
@@ -4,30 +4,21 @@ require 'chef/mixin/descendants_tracker'
 class Chef
   module Mixin
     module Provides
+      # TODO no longer needed, remove or deprecate?
       include Chef::Mixin::DescendantsTracker
 
-      def node_map
-        @node_map ||= Chef::NodeMap.new
-      end
-
       def provides(short_name, opts={}, &block)
-        if !short_name.kind_of?(Symbol)
-          # YAGNI: this is probably completely unnecessary and can be removed?
-          Chef::Log.deprecation "Passing a non-Symbol to Chef::Resource#provides will be removed"
-          if short_name.kind_of?(String)
-            short_name.downcase!
-            short_name.gsub!(/\s/, "_")
-          end
-          short_name = short_name.to_sym
-        end
-        node_map.set(short_name, true, opts, &block)
+        provides_priority_map.priority(short_name, self, opts, &block)
       end
 
       # Check whether this resource provides the resource_name DSL for the given
-      # node
-      def provides?(node, resource_name)
-        resource_name = resource_name.resource_name if resource_name.is_a?(Chef::Resource)
-        node_map.get(node, resource_name)
+      # node.
+      def provides?(node, short_name)
+        provides_priority_map.list(node, short_name).include?(self)
+      end
+
+      def provides_priority_map
+        raise NotImplementedError, :provides_priority_map
       end
 
       # Get the list of recipe DSL this resource is responsible for on the given
diff --git a/lib/chef/node_map.rb b/lib/chef/node_map.rb
index 2ca6d9ba17..7c25cb841a 100644
--- a/lib/chef/node_map.rb
+++ b/lib/chef/node_map.rb
@@ -68,14 +68,16 @@ class Chef
     def get(node, key)
       # FIXME: real exception
       raise "first argument must be a Chef::Node" unless node.is_a?(Chef::Node)
-      return nil unless @map.has_key?(key)
-      @map[key].each do |matcher|
-        if filters_match?(node, matcher[:filters]) &&
-          block_matches?(node, matcher[:block])
-          return matcher[:value]
-        end
-      end
-      nil
+      list(node, key).first
+    end
+
+    def list(node, key)
+      # FIXME: real exception
+      raise "first argument must be a Chef::Node" unless node.is_a?(Chef::Node)
+      return [] unless @map.has_key?(key)
+      @map[key].select do |matcher|
+        filters_match?(node, matcher[:filters]) && block_matches?(node, matcher[:block])
+      end.map { |matcher| matcher[:value] }
     end
 
     private
diff --git a/lib/chef/platform/provider_priority_map.rb b/lib/chef/platform/provider_priority_map.rb
index 1539f61900..2d250b5006 100644
--- a/lib/chef/platform/provider_priority_map.rb
+++ b/lib/chef/platform/provider_priority_map.rb
@@ -1,88 +1,28 @@
+require 'singleton'
 
 class Chef
   class Platform
     class ProviderPriorityMap
       include Singleton
 
-      def initialize
-        load_default_map
-      end
-
       def get_priority_array(node, resource_name)
         priority_map.get(node, resource_name.to_sym)
       end
 
       def set_priority_array(resource_name, priority_array, *filter)
-        priority(resource_name.to_sym, priority_array.to_a, *filter)
+        priority(resource_name.to_sym, Array(priority_array), *filter)
       end
 
       def priority(*args)
         priority_map.set(*args)
       end
 
-      private
-
-      def load_default_map
-        require 'chef/providers'
-
-        #
-        # Linux
-        #
-
-        # default block for linux O/Sen must come before platform_family exceptions
-        priority :service, [
-          Chef::Provider::Service::Systemd,
-          Chef::Provider::Service::Insserv,
-          Chef::Provider::Service::Redhat,
-        ], os: "linux"
-
-        priority :service, [
-          Chef::Provider::Service::Systemd,
-          Chef::Provider::Service::Arch,
-        ], platform_family: "arch"
-
-        priority :service, [
-          Chef::Provider::Service::Systemd,
-          Chef::Provider::Service::Gentoo,
-        ], platform_family: "gentoo"
-
-        priority :service, [
-          # we can determine what systemd supports accurately
-          Chef::Provider::Service::Systemd,
-          # on debian-ish system if an upstart script exists that must win over sysv types
-          Chef::Provider::Service::Upstart,
-          Chef::Provider::Service::Insserv,
-          Chef::Provider::Service::Debian,
-          Chef::Provider::Service::Invokercd,
-        ], platform_family: "debian"
-
-        priority :service, [
-          Chef::Provider::Service::Systemd,
-          Chef::Provider::Service::Insserv,
-          Chef::Provider::Service::Redhat,
-        ], platform_family: [ "rhel", "fedora", "suse" ]
-
-        #
-        # BSDen
-        #
-
-        priority :service, Chef::Provider::Service::Freebsd, os: [ "freebsd", "netbsd" ]
-        priority :service, Chef::Provider::Service::Openbsd, os: [ "openbsd" ]
-
-        #
-        # Solaris-en
-        #
-
-        priority :service, Chef::Provider::Service::Solaris, os: "solaris2"
-
-        #
-        # Mac
-        #
-
-        priority :service, Chef::Provider::Service::Macosx, os: "darwin"
-        priority :package, Chef::Provider::Package::Homebrew, os: "darwin"
+      def list(node, resource_name)
+        priority_map.list(node, resource_name).flatten(1).uniq
       end
 
+      private
+
       def priority_map
         require 'chef/node_map'
         @priority_map ||= Chef::NodeMap.new
diff --git a/lib/chef/platform/resource_priority_map.rb b/lib/chef/platform/resource_priority_map.rb
index fc43b3e7db..e692cbb800 100644
--- a/lib/chef/platform/resource_priority_map.rb
+++ b/lib/chef/platform/resource_priority_map.rb
@@ -1,33 +1,28 @@
+require 'singleton'
+
 class Chef
   class Platform
     class ResourcePriorityMap
       include Singleton
 
-      def initialize
-        load_default_map
-      end
-
       def get_priority_array(node, resource_name)
         priority_map.get(node, resource_name.to_sym)
       end
 
       def set_priority_array(resource_name, priority_array, *filter)
-        priority resource_name.to_sym, priority_array.to_a, *filter
+        priority resource_name.to_sym, Array(priority_array), *filter
       end
 
       def priority(*args)
         priority_map.set(*args)
       end
 
-      private
-
-      def load_default_map
-        require 'chef/resources'
-
-        # MacOSX
-        priority :package, Chef::Resource::HomebrewPackage, os: "darwin"
+      def list(*args)
+        priority_map.list(*args).flatten(1).uniq
       end
 
+      private
+
       def priority_map
         require 'chef/node_map'
         @priority_map ||= Chef::NodeMap.new
diff --git a/lib/chef/provider.rb b/lib/chef/provider.rb
index 42347a230e..52082123cb 100644
--- a/lib/chef/provider.rb
+++ b/lib/chef/provider.rb
@@ -29,6 +29,9 @@ require 'chef/node_map'
 
 class Chef
   class Provider
+    require 'chef/mixin/why_run'
+    require 'chef/mixin/shell_out'
+    require 'chef/mixin/provides'
     include Chef::Mixin::WhyRun
     include Chef::Mixin::ShellOut
     include Chef::Mixin::PowershellOut
@@ -174,6 +177,10 @@ class Chef
 
     protected
 
+    def self.provides_priority_map
+      Chef::Platform::ResourcePriorityMap.instance
+    end
+
     def converge_actions
       @converge_actions ||= ConvergeActions.new(@new_resource, run_context, @action)
     end
@@ -228,3 +235,9 @@ class Chef
     extend DeprecatedLWRPClass
   end
 end
+
+# Requiring things at the bottom breaks cycles
+require 'chef/chef_class'
+require 'chef/mixin/why_run'
+require 'chef/resource_collection'
+require 'chef/runner'
diff --git a/lib/chef/provider/file.rb b/lib/chef/provider/file.rb
index 4ce2c040a4..5ed7c6ac5b 100644
--- a/lib/chef/provider/file.rb
+++ b/lib/chef/provider/file.rb
@@ -26,6 +26,7 @@ require 'fileutils'
 require 'chef/scan_access_control'
 require 'chef/mixin/checksum'
 require 'chef/mixin/file_class'
+require 'chef/mixin/enforce_ownership_and_permissions'
 require 'chef/util/backup'
 require 'chef/util/diff'
 require 'chef/util/selinux'
diff --git a/lib/chef/provider/package.rb b/lib/chef/provider/package.rb
index bdc96cd070..86c158f23d 100644
--- a/lib/chef/provider/package.rb
+++ b/lib/chef/provider/package.rb
@@ -493,3 +493,8 @@ class Chef
     end
   end
 end
+
+require 'chef/chef_class'
+require 'chef/provider/package/homebrew'
+
+Chef.set_provider_priority_array :package, Chef::Provider::Package::Homebrew, os: "darwin"
diff --git a/lib/chef/provider/service.rb b/lib/chef/provider/service.rb
index 75da2ddb31..4cd7f335dd 100644
--- a/lib/chef/provider/service.rb
+++ b/lib/chef/provider/service.rb
@@ -171,3 +171,77 @@ class Chef
     end
   end
 end
+
+#
+# Platform-specific versions
+#
+
+#
+# Linux
+#
+
+require 'chef/chef_class'
+require 'chef/provider/service/systemd'
+require 'chef/provider/service/insserv'
+require 'chef/provider/service/redhat'
+require 'chef/provider/service/arch'
+require 'chef/provider/service/gentoo'
+require 'chef/provider/service/upstart'
+require 'chef/provider/service/debian'
+require 'chef/provider/service/invokercd'
+require 'chef/provider/service/freebsd'
+require 'chef/provider/service/openbsd'
+require 'chef/provider/service/solaris'
+require 'chef/provider/service/macosx'
+
+# default block for linux O/Sen must come before platform_family exceptions
+Chef.set_provider_priority_array :service, [
+  Chef::Provider::Service::Systemd,
+  Chef::Provider::Service::Insserv,
+  Chef::Provider::Service::Redhat,
+], os: "linux"
+
+Chef.set_provider_priority_array :service, [
+  Chef::Provider::Service::Systemd,
+  Chef::Provider::Service::Arch,
+], platform_family: "arch"
+
+Chef.set_provider_priority_array :service, [
+  Chef::Provider::Service::Systemd,
+  Chef::Provider::Service::Gentoo,
+], platform_family: "gentoo"
+
+Chef.set_provider_priority_array :service, [
+  # we can determine what systemd supports accurately
+  Chef::Provider::Service::Systemd,
+  # on debian-ish system if an upstart script exists that must win over sysv types
+  Chef::Provider::Service::Upstart,
+  Chef::Provider::Service::Insserv,
+  Chef::Provider::Service::Debian,
+  Chef::Provider::Service::Invokercd,
+], platform_family: "debian"
+
+Chef.set_provider_priority_array :service, [
+  Chef::Provider::Service::Systemd,
+  Chef::Provider::Service::Insserv,
+  Chef::Provider::Service::Redhat,
+], platform_family: [ "rhel", "fedora", "suse" ]
+
+#
+# BSDen
+#
+
+Chef.set_provider_priority_array :service, Chef::Provider::Service::Freebsd, os: [ "freebsd", "netbsd" ]
+Chef.set_provider_priority_array :service, Chef::Provider::Service::Openbsd, os: [ "openbsd" ]
+
+#
+# Solaris-en
+#
+
+Chef.set_provider_priority_array :service, Chef::Provider::Service::Solaris, os: "solaris2"
+
+#
+# Mac
+#
+
+Chef.set_provider_priority_array :service, Chef::Provider::Service::Macosx, os: "darwin"
diff --git a/lib/chef/provider/service/init.rb b/lib/chef/provider/service/init.rb
index 0a219a69e1..355e98a0eb 100644
--- a/lib/chef/provider/service/init.rb
+++ b/lib/chef/provider/service/init.rb
@@ -18,6 +18,7 @@
 
 require 'chef/provider/service/simple'
 require 'chef/mixin/command'
+require 'chef/platform/service_helpers'
 
 class Chef
   class Provider
diff --git a/lib/chef/resource.rb b/lib/chef/resource.rb
index 070793a7a2..686b212e49 100644
--- a/lib/chef/resource.rb
+++ b/lib/chef/resource.rb
@@ -1103,7 +1103,7 @@ class Chef
       end
     end
 
-    def self.provides(name, *args, &block)
+    def self.provides(name, opts={}, &block)
       result = super
       Chef::DSL::Resources.add_resource_dsl(name)
       result
@@ -1270,6 +1270,12 @@ class Chef
       end
     end
 
+    protected
+
+    def self.provides_priority_map
+      Chef::Platform::ResourcePriorityMap.instance
+    end
+
     # Implement deprecated LWRP class
     module DeprecatedLWRPClass
       # @api private
@@ -1290,8 +1296,6 @@ class Chef
         end
       end
 
-      private
-
       def deprecated_constants
         @deprecated_constants ||= {}
       end
diff --git a/lib/chef/resource/package.rb b/lib/chef/resource/package.rb
index 4148144816..0944b5e9d8 100644
--- a/lib/chef/resource/package.rb
+++ b/lib/chef/resource/package.rb
@@ -102,3 +102,8 @@ class Chef
     end
   end
 end
+
+require 'chef/chef_class'
+require 'chef/resource/homebrew_package'
+
+Chef.set_resource_priority_array :package, Chef::Resource::HomebrewPackage, os: "darwin"
diff --git a/lib/chef/resource_resolver.rb b/lib/chef/resource_resolver.rb
index a987b236c2..47d98154a8 100644
--- a/lib/chef/resource_resolver.rb
+++ b/lib/chef/resource_resolver.rb
@@ -75,11 +75,6 @@ class Chef
         # this magic stack ranks the resources by where they appear in the resource_priority_map
         priority_list = [ get_priority_array(node, resource) ].flatten.compact
         handlers = handlers.sort_by { |x| i = priority_list.index x; i.nil? ? Float::INFINITY : i }
-        if priority_list.index(handlers.first).nil?
-          # if we had more than one and we picked one with a precidence of infinity that means that the resource_priority_map
-          # entry for this resource is missing -- we should probably raise here and force resolution of the ambiguity.
-          Chef::Log.warn "Ambiguous resource precedence: #{handlers}, please use Chef.set_resource_priority_array to provide determinism"
-        end
         handlers = handlers[0..0]
       end
 
diff --git a/lib/chef/util/path_helper.rb b/lib/chef/util/path_helper.rb
index 10527f8906..1fddfed9b8 100644
--- a/lib/chef/util/path_helper.rb
+++ b/lib/chef/util/path_helper.rb
@@ -16,11 +16,208 @@
 # limitations under the License.
 #
 
-require 'chef-config/path_helper'
-
 class Chef
   class Util
-    PathHelper = ChefConfig::PathHelper
+    class PathHelper
+      # Maximum characters in a standard Windows path (260 including drive letter and NUL)
+      WIN_MAX_PATH = 259
+
+      def self.dirname(path)
+        if Chef::Platform.windows?
+          # Find the first slash, not counting trailing slashes
+          end_slash = path.size
+          loop do
+            slash = path.rindex(/[#{Regexp.escape(File::SEPARATOR)}#{Regexp.escape(path_separator)}]/, end_slash - 1)
+            if !slash
+              return end_slash == path.size ? '.' : path_separator
+            elsif slash == end_slash - 1
+              end_slash = slash
+            else
+              return path[0..slash-1]
+            end
+          end
+        else
+          ::File.dirname(path)
+        end
+      end
+
+      BACKSLASH = '\\'.freeze
+
+      def self.path_separator
+        if Chef::Platform.windows?
+          File::ALT_SEPARATOR || BACKSLASH
+        else
+          File::SEPARATOR
+        end
+      end
+
+      def self.join(*args)
+        args.flatten.inject do |joined_path, component|
+          # Joined path ends with /
+          joined_path = joined_path.sub(/[#{Regexp.escape(File::SEPARATOR)}#{Regexp.escape(path_separator)}]+$/, '')
+          component = component.sub(/^[#{Regexp.escape(File::SEPARATOR)}#{Regexp.escape(path_separator)}]+/, '')
+          joined_path += "#{path_separator}#{component}"
+        end
+      end
+
+      def self.validate_path(path)
+        if Chef::Platform.windows?
+          unless printable?(path)
+            msg = "Path '#{path}' contains non-printable characters. Check that backslashes are escaped with another backslash (e.g. C:\\\\Windows) in double-quoted strings."
+            Chef::Log.error(msg)
+            raise Chef::Exceptions::ValidationFailed, msg
+          end
+
+          if windows_max_length_exceeded?(path)
+            Chef::Log.debug("Path '#{path}' is longer than #{WIN_MAX_PATH}, prefixing with'\\\\?\\'")
+            path.insert(0, "\\\\?\\")
+          end
+        end
+
+        path
+      end
+
+      def self.windows_max_length_exceeded?(path)
+        # Check to see if paths without the \\?\ prefix are over the maximum allowed length for the Windows API
+        # http://msdn.microsoft.com/en-us/library/windows/desktop/aa365247%28v=vs.85%29.aspx
+        unless path =~ /^\\\\?\\/
+          if path.length > WIN_MAX_PATH
+            return true
+          end
+        end
+
+        false
+      end
+
+      def self.printable?(string)
+        # returns true if string is free of non-printable characters (escape sequences)
+        # this returns false for whitespace escape sequences as well, e.g. \n\t
+        if string =~ /[^[:print:]]/
+          false
+        else
+          true
+        end
+      end
+
+      # Produces a comparable path.
+      def self.canonical_path(path, add_prefix=true)
+        # First remove extra separators and resolve any relative paths
+        abs_path = File.absolute_path(path)
+
+        if Chef::Platform.windows?
+          # Add the \\?\ API prefix on Windows unless add_prefix is false
+          # Downcase on Windows where paths are still case-insensitive
+          abs_path.gsub!(::File::SEPARATOR, path_separator)
+          if add_prefix && abs_path !~ /^\\\\?\\/
+            abs_path.insert(0, "\\\\?\\")
+          end
+
+          abs_path.downcase!
+        end
+
+        abs_path
+      end
+
+      def self.cleanpath(path)
+        path = Pathname.new(path).cleanpath.to_s
+        # ensure all forward slashes are backslashes
+        if Chef::Platform.windows?
+          path = path.gsub(File::SEPARATOR, path_separator)
+        end
+        path
+      end
+
+      def self.paths_eql?(path1, path2)
+        canonical_path(path1) == canonical_path(path2)
+      end
+
+      # Paths which may contain glob-reserved characters need
+      # to be escaped before globbing can be done.
+      # http://stackoverflow.com/questions/14127343
+      def self.escape_glob(*parts)
+        path = cleanpath(join(*parts))
+        path.gsub(/[\\\{\}\[\]\*\?]/) { |x| "\\"+x }
+      end
+
+      def self.relative_path_from(from, to)
+        pathname = Pathname.new(Chef::Util::PathHelper.cleanpath(to)).relative_path_from(Pathname.new(Chef::Util::PathHelper.cleanpath(from)))
+      end
+
+      # Retrieves the "home directory" of the current user while trying to ascertain the existence
+      # of said directory.  The path returned uses / for all separators (the ruby standard format).
+      # If the home directory doesn't exist or an error is otherwise encountered, nil is returned.
+      #
+      # If a set of path elements is provided, they are appended as-is to the home path if the
+      # homepath exists.
+      #
+      # If an optional block is provided, the joined path is passed to that block if the home path is
+      # valid and the result of the block is returned instead.
+      #
+      # Home-path discovery is performed once.  If a path is discovered, that value is memoized so
+      # that subsequent calls to home_dir don't bounce around.
+      #
+      # See self.all_homes.
+      def self.home(*args)
+        @@home_dir ||= self.all_homes { |p| break p }
+        if @@home_dir
+          path = File.join(@@home_dir, *args)
+          block_given? ? (yield path) : path
+        end
+      end
+
+      # See self.home.  This method performs a similar operation except that it yields all the different
+      # possible values of 'HOME' that one could have on this platform.  Hence, on windows, if
+      # HOMEDRIVE\HOMEPATH and USERPROFILE are different, the provided block will be called twice.
+      # This method goes out and checks the existence of each location at the time of the call.
+      #
+      # The return is a list of all the returned values from each block invocation or a list of paths
+      # if no block is provided.
+      def self.all_homes(*args)
+        paths = []
+        if Chef::Platform.windows?
+          # By default, Ruby uses the the following environment variables to determine Dir.home:
+          # HOME
+          # HOMEDRIVE HOMEPATH
+          # USERPROFILE
+          # Ruby only checks to see if the variable is specified - not if the directory actually exists.
+          # On Windows, HOMEDRIVE HOMEPATH can point to a different location (such as an unavailable network mounted drive)
+          # while USERPROFILE points to the location where the user application settings and profile are stored.  HOME
+          # is not defined as an environment variable (usually).  If the home path actually uses UNC, then the prefix is
+          # HOMESHARE instead of HOMEDRIVE.
+          #
+          # We instead walk down the following and only include paths that actually exist.
+          # HOME
+          # HOMEDRIVE HOMEPATH
+          # HOMESHARE HOMEPATH
+          # USERPROFILE
+
+          paths << ENV['HOME']
+          paths << ENV['HOMEDRIVE'] + ENV['HOMEPATH'] if ENV['HOMEDRIVE'] && ENV['HOMEPATH']
+          paths << ENV['HOMESHARE'] + ENV['HOMEPATH'] if ENV['HOMESHARE'] && ENV['HOMEPATH']
+          paths << ENV['USERPROFILE']
+        end
+        paths << Dir.home if ENV['HOME']
+
+        # Depending on what environment variables we're using, the slashes can go in any which way.
+        # Just change them all to / to keep things consistent.
+        # Note: Maybe this is a bad idea on some unixy systems where \ might be a valid character depending on
+        # the particular brand of kool-aid you consume.  This code assumes that \ and / are both
+        # path separators on any system being used.
+        paths = paths.map { |home_path| home_path.gsub(path_separator, ::File::SEPARATOR) if home_path }
+
+        # Filter out duplicate paths and paths that don't exist.
+        valid_paths = paths.select { |home_path| home_path && Dir.exists?(home_path) }
+        valid_paths = valid_paths.uniq
+
+        # Join all optional path elements at the end.
+        # If a block is provided, invoke it - otherwise just return what we've got.
+        joined_paths = valid_paths.map { |home_path| File.join(home_path, *args) }
+        if block_given?
+          joined_paths.each { |p| yield p }
+        else
+          joined_paths
+        end
+      end
+    end
   end
 end
-