core: no active machines if there is no vagrant env

CHANGELOG.md

@@ -6,6 +6,8 @@ IMPROVEMENTS:
 
 BUG FIXES:
 
+  - core: Global control works from directories that don't have a
+      Vagrantfile.
   - commands/package: `--base` works without crashing for VirtualBox.
   - guests/redhat: Fix networking issues with CentOS. [GH-3649]
 

lib/vagrant/environment.rb

@@ -191,6 +191,9 @@ module Vagrant
     #
     # @return [Array<String, Symbol>]
     def active_machines
+      # We have no active machines if we have no data path
+      return [] if !@local_data_path
+
       machine_folder = @local_data_path.join("machines")
 
       # If the machine folder is not a directory then we just return

test/unit/vagrant/environment_test.rb

@@ -602,6 +602,13 @@ VF
   end
 
   describe "active machines" do
+    it "should be empty if there is no root path" do
+      Dir.mktmpdir do |temp_dir|
+        instance = described_class.new(cwd: temp_dir)
+        expect(instance.active_machines).to be_empty
+      end
+    end
+
     it "should be empty if the machines folder doesn't exist" do
       folder = instance.local_data_path.join("machines")
       expect(folder).not_to be_exist