guests/linux: Update network interface sorting implementation

Always pull ordered ethernet devices to the head of the list. Ensure
aliases are not included.

plugins/guests/linux/cap/network_interfaces.rb

@@ -20,16 +20,10 @@ module VagrantPlugins
             s << data if type == :stdout
           end
           ifaces = s.split("\n")
-          eth_prefix = nil
           @@logger.debug("Unsorted list: #{ifaces.inspect}")
           # Break out integers from strings and sort the arrays to provide
           # a natural sort for the interface names
           ifaces = ifaces.map do |iface|
-            if eth_prefix.nil?
-              eth_prefix = POSSIBLE_ETHERNET_PREFIXES.detect do |prefix|
-                iface.start_with?(prefix)
-              end
-            end
             iface.scan(/(.+?)(\d+)/).flatten.map do |iface_part|
               if iface_part.to_i.to_s == iface_part
                 iface_part.to_i
@@ -40,12 +34,14 @@ module VagrantPlugins
           end.sort.map(&:join)
           @@logger.debug("Sorted list: #{ifaces.inspect}")
           # Extract ethernet devices and place at start of list
-          if eth_prefix
+          resorted_ifaces = []
-            eth_start = ifaces.index{|iface| iface.start_with?(eth_prefix) }
+          resorted_ifaces += ifaces.find_all do |iface|
-            eth_end = ifaces.rindex{|iface| iface.start_with?(eth_prefix) }
+            POSSIBLE_ETHERNET_PREFIXES.any?{|prefix| iface.start_with?(prefix)} &&
-            ifaces.unshift(*ifaces.slice!(eth_start, eth_end - 1))
+              !iface.include?(':')
-            @@logger.debug("Ethernet preferred sorted list: #{ifaces.inspect}")
           end
+          resorted_ifaces += ifaces - resorted_ifaces
+          ifaces = resorted_ifaces
+          @@logger.debug("Ethernet preferred sorted list: #{ifaces.inspect}")
           ifaces
         end
       end

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

@@ -56,5 +56,17 @@ describe "VagrantPlugins::GuestLinux::Cap::NetworkInterfaces" do
       result = cap.network_interfaces(machine)
       expect(result).to eq(["enp0s3", "enp0s5", "enp0s8", "bridge0", "docker0"])
     end
+
+    it "sorts ethernet devices discovered with predictable network interfaces naming first in list with less" do
+      expect(comm).to receive(:sudo).and_yield(:stdout, "enp0s3\nenp0s8\ndocker0")
+      result = cap.network_interfaces(machine)
+      expect(result).to eq(["enp0s3", "enp0s8", "docker0"])
+    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")
+      result = cap.network_interfaces(machine)
+      expect(result).to eq(["eth0", "eth1", "eth2", "bridge0", "docker0", "eth0:0"])
+    end
   end
 end