Merge pull request #7756 from alexoj/master

Fix Vagrant not prioritizing configured providers correctly

lib/vagrant/environment.rb

@@ -338,7 +338,7 @@ module Vagrant
       # a priority to each in the order they exist so that we try these first.
       config = {}
       root_config.vm.__providers.reverse.each_with_index do |key, idx|
-        config[key] = idx
+        config[key] = idx + 1
       end
 
       # Determine the max priority so that we can add the config priority

test/unit/vagrant/environment_test.rb

@@ -866,6 +866,30 @@ VF
       end
     end
 
+    it "is the provider in the Vagrantfile that is usable even if only one specified (1)" do
+      subject.vagrantfile.config.vm.provider "foo"
+      subject.vagrantfile.config.vm.finalize!
+
+      plugin_providers[:foo] = [provider_usable_class(true), { priority: 5 }]
+      plugin_providers[:bar] = [provider_usable_class(true), { priority: 7 }]
+
+      with_temp_env("VAGRANT_DEFAULT_PROVIDER" => nil) do
+        expect(subject.default_provider).to eq(:foo)
+      end
+    end
+
+    it "is the provider in the Vagrantfile that is usable even if only one specified (2)" do
+      subject.vagrantfile.config.vm.provider "bar"
+      subject.vagrantfile.config.vm.finalize!
+
+      plugin_providers[:foo] = [provider_usable_class(true), { priority: 7 }]
+      plugin_providers[:bar] = [provider_usable_class(true), { priority: 5 }]
+
+      with_temp_env("VAGRANT_DEFAULT_PROVIDER" => nil) do
+        expect(subject.default_provider).to eq(:bar)
+      end
+    end
+
     it "is the highest usable provider outside the Vagrantfile" do
       subject.vagrantfile.config.vm.provider "foo"
       subject.vagrantfile.config.vm.finalize!