Fixes to package upgrade behaviour

This commit introduces fixes to the behaviour of the various providers of the "package" resource (and subtypes like dnf_package etc) when a more recent version of the package has been installed than that present in an available repository or file source and "action :upgrade" is called against the package.

Currently, a number of package providers will attempt to downgrade a package under this scenario, where the desired action should be to recognise that a more up to date version is already installed and do nothing.

I've introduced a ```version_compare``` method to the package superclass which by default uses ```Gem::Version``` comparison with spaceship-operator semantics to ensure that an upgrade is attempted only when the candidate version is not older than the current version.

Additionally, this commit introduces a method called ```version_equals?``` which is functionally identical to ```target_version_already_installed?``` (and that method now in fact calls ```version_equals?```. This has been done to clarify the purpose and functionality of that method, but since it's a public API, deprecation of the old method name will have to be done more gradually.

Signed-off-by: Jon Cowie <jcowie@chef.io>

1 files changed, 5 insertions, 0 deletions

diff --git a/lib/chef/provider/package/rpm.rb b/lib/chef/provider/package/rpm.rb
index 7ec24f8c24..07617c814e 100644
--- a/lib/chef/provider/package/rpm.rb
+++ b/lib/chef/provider/package/rpm.rb
@@ -18,6 +18,7 @@
 require "chef/provider/package"
 require "chef/resource/package"
 require "chef/mixin/get_source_from_package"
+require "chef/provider/package/yum/rpm_utils"
 
 class Chef
   class Provider
@@ -109,6 +110,10 @@ class Chef
 
         private
 
+        def version_compare(v1, v2)
+          Chef::Provider::Package::Yum::RPMVersion.parse(v1) <=> Chef::Provider::Package::Yum::RPMVersion.parse(v2)
+        end
+
         def uri_scheme?(str)
           scheme = URI.split(str).first
           return false unless scheme