Prevent URI parse errors when checking box name

Fixes #8758

lib/vagrant/action/builtin/box_add.rb

@@ -31,8 +31,12 @@ module Vagrant
           @download_interrupted = false
 
           unless env[:box_name].nil?
-            if URI.parse(env[:box_name]).kind_of?(URI::HTTP)
-              env[:ui].warn(I18n.t("vagrant.box_add_url_warn"))
+            begin
+              if URI.parse(env[:box_name]).kind_of?(URI::HTTP)
+                env[:ui].warn(I18n.t("vagrant.box_add_url_warn"))
+              end
+            rescue URI::InvalidURIError
+              # do nothing
             end
           end
 

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

@@ -305,6 +305,28 @@ describe Vagrant::Action::Builtin::BoxAdd, :skip_windows do
       end
     end
 
+    context "with a box name containing invalid URI characters" do
+      it "should not raise an error" do
+        box_path = iso_env.box2_file(:virtualbox)
+        with_web_server(box_path) do |port|
+
+          box_url_name = "box name with spaces"
+          env[:box_name] = box_url_name
+
+          expect(box_collection).to receive(:add).with { |path, name, version, **opts|
+            expect(name).to eq(box_url_name)
+            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
+    end
+
     context "with URL containing credentials" do
       let(:username){ "box-username" }
       let(:password){ "box-password" }