guests/linux: Properly sort interface name types

Add failing networking interface list sorting test with example
provided by #7883. Update sorting logic to properly handle different
types and differing array lengths.

Fixes #7883

plugins/guests/linux/cap/network_interfaces.rb

@@ -23,6 +23,9 @@ def self.network_interfaces(machine, path = "/sbin/ip")
           @@logger.debug("Unsorted list: #{ifaces.inspect}")
           # Break out integers from strings and sort the arrays to provide
           # a natural sort for the interface names
+          # NOTE: Devices named with a hex value suffix will _not_ be sorted
+          #  as expected. This is generally seen with veth* devices, and proper ordering
+          #  is currently not required
           ifaces = ifaces.map do |iface|
             iface.scan(/(.+?)(\d+)/).flatten.map do |iface_part|
               if iface_part.to_i.to_s == iface_part
@@ -31,7 +34,22 @@ def self.network_interfaces(machine, path = "/sbin/ip")
                 iface_part
               end
             end
-          end.sort.map(&:join)
+          end
+          ifaces = ifaces.sort do |lhs, rhs|
+            result = 0
+            slice_length = [rhs.size, lhs.size].min
+            slice_length.times do |idx|
+              if(lhs[idx].is_a?(rhs[idx].class))
+                result = lhs[idx] <=> rhs[idx]
+              elsif(lhs[idx].is_a?(String))
+                result = 1
+              else
+                result = -1
+              end
+              break if result != 0
+            end
+            result
+          end.map(&:join)
           @@logger.debug("Sorted list: #{ifaces.inspect}")
           # Extract ethernet devices and place at start of list
           resorted_ifaces = []

test/unit/plugins/guests/linux/cap/network_interfaces_test.rb

@@ -64,9 +64,15 @@
     end
 
     it "does not include ethernet devices aliases within prefix device listing" do
-      expect(comm).to receive(:sudo).and_yield(:stdout, "eth1\neth2\ndocker0\nbridge0\neth0\neth0:0")
+      expect(comm).to receive(:sudo).and_yield(:stdout, "eth1\neth2\ndocker0\nbridge0\neth0\ndocker1\neth0:0")
       result = cap.network_interfaces(machine)
-      expect(result).to eq(["eth0", "eth1", "eth2", "bridge0", "docker0", "eth0:0"])
+      expect(result).to eq(["eth0", "eth1", "eth2", "bridge0", "docker0", "docker1", "eth0:0"])
+    end
+
+    it "properly sorts non-consistent device name formats" do
+      expect(comm).to receive(:sudo).and_yield(:stdout, "eth0\neth1\ndocker0\nveth437f7f9\nveth06b3e44\nveth8bb7081")
+      result = cap.network_interfaces(machine)
+      expect(result).to eq(["eth0", "eth1", "docker0", "veth8bb7081", "veth437f7f9", "veth06b3e44"])
     end
   end
 end