# Make pip version available as a fact
# Works with pip loaded and without, pip installed using pip  and package installed
require 'puppet'
pkg = Puppet::Type.type(:package).new(:name => "python-pip")
Facter.add("pip_version") do
  has_weight 100
  setcode do
    begin
      /^pip (\d+\.\d+\.?\d*).*$/.match(Facter::Util::Resolution.exec('pip --version 2>/dev/null'))[1]
    rescue
      false
    end
  end
end

Facter.add("pip_version") do
  has_weight 50
  setcode do
    begin
      unless [:absent,'purged'].include?(pkg.retrieve[pkg.property(:ensure)])
          /^.*(\d+\.\d+\.\d+).*$/.match(pkg.retrieve[pkg.property(:ensure)])[1]
      end
    rescue
      false
    end
  end
end

# Make pip version available as a fact
# Works with pip loaded and without, pip installed using pip  and package installed
require 'puppet'
pkg = Puppet::Type.type(:package).new(:name => "python-pip")
Facter.add("pip_version") do
  has_weight 100
  setcode do
    /^pip (\d+\.\d+\.?\d*).*$/.match(Facter::Util::Resolution.exec('pip --version 2>/dev/null'))[1]
  end
end

Facter.add("pip_version") do
  has_weight 50
  setcode do
    unless [:absent,'purged'].include?(pkg.retrieve[pkg.property(:ensure)])
        /^.*(\d+\.\d+\.\d+).*$/.match(pkg.retrieve[pkg.property(:ensure)])[1]
    end
  end
end

--- 
+++ 
@@ -5,15 +5,23 @@
 Facter.add("pip_version") do
   has_weight 100
   setcode do
-    /^pip (\d+\.\d+\.?\d*).*$/.match(Facter::Util::Resolution.exec('pip --version 2>/dev/null'))[1]
+    begin
+      /^pip (\d+\.\d+\.?\d*).*$/.match(Facter::Util::Resolution.exec('pip --version 2>/dev/null'))[1]
+    rescue
+      false
+    end
   end
 end
 
 Facter.add("pip_version") do
   has_weight 50
   setcode do
-    unless [:absent,'purged'].include?(pkg.retrieve[pkg.property(:ensure)])
-        /^.*(\d+\.\d+\.\d+).*$/.match(pkg.retrieve[pkg.property(:ensure)])[1]
+    begin
+      unless [:absent,'purged'].include?(pkg.retrieve[pkg.property(:ensure)])
+          /^.*(\d+\.\d+\.\d+).*$/.match(pkg.retrieve[pkg.property(:ensure)])[1]
+      end
+    rescue
+      false
     end
   end
 end
Add begin/rescue/end to setcode block

This silences these warnings:

Could not retrieve pip_version: undefined method `[]' for nil:NilClass
Could not retrieve pip_version: can't convert Symbol into String
