Define custom port_check method for halted docker containers

lib/vagrant/action/builtin/handle_forwarded_port_collisions.rb

@@ -124,16 +124,6 @@ module Vagrant
               call_port_checker(port_checker, host_ip, host_port) ||
               lease_check(host_ip, host_port)
 
-            # This check is required only for the docker provider. Containers
-            # can bind ports but be halted. We don't want new containers to
-            # grab these bound ports, so this check is here for that since
-            # the checks above won't detect it
-            if !in_use && env[:machine].provider_name == :docker
-              if extra_in_use.keys.include?(host_port.to_s)
-                in_use = true
-              end
-            end
-
             if in_use
               if !repair || !options[:auto_correct]
                 raise Errors::ForwardPortCollision,

plugins/providers/docker/action/prepare_forwarded_port_collision_params.rb

@@ -15,14 +15,46 @@ module VagrantPlugins
           env[:port_collision_extra_in_use] = other_used_ports
 
           # Build the remap for any existing collision detections
+          #
+          # Note: This remap might not be required yet (as it is with the virtualbox provider)
+          # so for now we leave the remap hash empty.
           remap = {}
           env[:port_collision_remap] = remap
 
-          # Note: This might not be required yet (as it is with the virtualbox provider)
-          # so for now we leave the remap hash empty.
+          # This port checker method calls the custom port_check method
+          # defined below. If its false, it will go ahead and use the built-in
+          # port_check method to see if there are any live containers with bound
+          # ports
+          docker_port_check = proc { |host_ip, host_port|
+                                      result = port_check(env, host_port)
+                                      if !result
+                                        result = Vagrant::Action::Builtin::HandleForwardedPortCollisions.port_check(machine, host_ip, host_port)
+                                      end
+                                      result}
+          env[:port_collision_port_check] = docker_port_check
 
           @app.call(env)
         end
+
+        protected
+
+        # This check is required the docker provider. Containers
+        # can bind ports but be halted. We don't want new containers to
+        # grab these bound ports, so this check is here for that since
+        # the checks above won't detect it
+        #
+        # @param [Vagrant::Environment] env
+        # @param [String] host_port
+        # @returns [Bool]
+        def port_check(env, host_port)
+          extra_in_use = env[:port_collision_extra_in_use]
+
+          if extra_in_use
+            return extra_in_use.include?(host_port.to_s)
+          else
+            return false
+          end
+        end
       end
     end
   end