core: Can exclude providers

lib/vagrant/environment.rb

@@ -253,6 +253,7 @@ module Vagrant
     #
     # @return [Symbol] Name of the default provider.
     def default_provider(**opts)
+      opts[:exclude]       = Set.new(opts[:exclude]) if opts[:exclude]
       opts[:force_default] = true if !opts.has_key?(:force_default)
 
       default = ENV["VAGRANT_DEFAULT_PROVIDER"]
@@ -266,9 +267,12 @@ module Vagrant
       ordered = []
       Vagrant.plugin("2").manager.providers.each do |key, data|
         impl  = data[0]
-        opts = data[1]
+        popts = data[1]
 
-        ordered << [opts[:priority], key, impl, opts]
+        # Skip excluded providers
+        next if opts[:exclude] && opts[:exclude].include?(key)
+
+        ordered << [popts[:priority], key, impl, popts]
       end
 
       # Order the providers by priority. Higher values are tried first.

test/unit/vagrant/environment_test.rb

@@ -717,6 +717,17 @@ VF
       end
     end
 
+    it "is the highest matching usable provider that isn't excluded" do
+      plugin_providers[:foo] = [provider_usable_class(true), { priority: 5 }]
+      plugin_providers[:bar] = [provider_usable_class(true), { priority: 7 }]
+      plugin_providers[:baz] = [provider_usable_class(true), { priority: 2 }]
+      plugin_providers[:boom] = [provider_usable_class(true), { priority: 3 }]
+
+      with_temp_env("VAGRANT_DEFAULT_PROVIDER" => nil) do
+        expect(subject.default_provider(exclude: [:bar, :foo])).to eq(:boom)
+      end
+    end
+
     it "is the default provider set if usable" do
       plugin_providers[:foo] = [provider_usable_class(true), { priority: 5 }]
       plugin_providers[:bar] = [provider_usable_class(true), { priority: 7 }]