core: don't do HEAD request for box on non-HTTP [GH-5477]

lib/vagrant/action/builtin/box_add.rb

@@ -491,6 +491,9 @@ def metadata_url?(url, env)
             end
           end
 
+          # If this isn't HTTP, then don't do the HEAD request
+          return false if !uri.scheme.downcase.start_with?("http")
+
           output = d.head
           match  = output.scan(/^Content-Type: (.+?)$/i).last
           return false if !match

test/unit/vagrant/action/builtin/box_add_test.rb

@@ -4,6 +4,8 @@
 require "tmpdir"
 require "webrick"
 
+require "fake_ftp"
+
 require File.expand_path("../../../../base", __FILE__)
 
 require "vagrant/util/file_checksum"
@@ -34,6 +36,21 @@ def checksum(path)
     FileChecksum.new(path, Digest::SHA1).checksum
   end
 
+  def with_ftp_server(path, **opts)
+    path = Pathname.new(path)
+
+    tf = Tempfile.new("vagrant")
+    tf.close
+
+    port   = 21212
+    server = FakeFtp::Server.new(port, port+1)
+    server.add_file(path.basename, path.read)
+    server.start
+    yield port
+  ensure
+    server.stop rescue nil
+  end
+
   def with_web_server(path, **opts)
     tf = Tempfile.new("vagrant")
     tf.close
@@ -123,6 +140,26 @@ def with_web_server(path, **opts)
       end
     end
 
+    it "adds from FTP URL" do
+      box_path = iso_env.box2_file(:virtualbox)
+      with_ftp_server(box_path) do |port|
+        env[:box_name] = "foo"
+        env[:box_url] = "ftp://127.0.0.1:#{port}/#{box_path.basename}"
+
+        expect(box_collection).to receive(:add).with { |path, name, version, **opts|
+          expect(checksum(path)).to eq(checksum(box_path))
+          expect(name).to eq("foo")
+          expect(version).to eq("0")
+          expect(opts[:metadata_url]).to be_nil
+          true
+        }.and_return(box)
+
+        expect(app).to receive(:call).with(env)
+
+        subject.call(env)
+      end
+    end
+
     it "raises an error if no name is given" do
       box_path = iso_env.box2_file(:virtualbox)