core: Machine#reload

lib/vagrant/machine.rb

@@ -115,10 +115,7 @@ module Vagrant
       if base
         @id = name
       else
-        # Read the id file from the data directory if it exists as the
+        reload
-        # ID for the pre-existing physical representation of this machine.
-        id_file = @data_dir.join("id")
-        @id = id_file.read.chomp if id_file.file?
       end
 
       # Keep track of where our UUID should be placed
@@ -340,6 +337,18 @@ module Vagrant
       "#<#{self.class}: #{@name} (#{@provider.class})>"
     end
 
+    # This reloads the ID of the underlying machine.
+    def reload
+      @id = nil
+
+      if @data_dir
+        # Read the id file from the data directory if it exists as the
+        # ID for the pre-existing physical representation of this machine.
+        id_file = @data_dir.join("id")
+        @id = id_file.read.chomp if id_file.file?
+      end
+    end
+
     # This returns the SSH info for accessing this machine. This SSH info
     # is queried from the underlying provider. This method returns `nil` if
     # the machine is not ready for SSH communication.

test/unit/vagrant/machine_test.rb

@@ -448,6 +448,28 @@ describe Vagrant::Machine do
     end
   end
 
+  describe "#reload" do
+    before do
+      allow(provider).to receive(:machine_id_changed)
+
+      subject.id = "foo"
+    end
+
+    it "should read the ID" do
+      subject.reload
+
+      expect(subject.id).to eq("foo")
+    end
+
+    it "should read the updated ID" do
+      new_instance.id = "bar"
+
+      subject.reload
+
+      expect(subject.id).to eq("bar")
+    end
+  end
+
   describe "ssh info" do
     describe "with the provider returning nil" do
       it "should return nil if the provider returns nil" do