Emit warning message if using mfsymlink

plugins/guests/linux/cap/mount_smb_shared_folder.rb

@@ -1,3 +1,4 @@
+require "fileutils"
 require "shellwords"
 require_relative "../../../synced_folders/unix_mount_helpers"
 
@@ -41,6 +42,10 @@ module VagrantPlugins
           mnt_opts = merge_mount_options(mnt_opts, options[:mount_options] || [])
 
           mount_options = "-o #{mnt_opts.join(",")}"
+          if mount_options.include?("mfsymlinks")
+            display_mfsymlinks_warning(machine.env)
+          end
+          
           mount_command = "mount -t cifs #{mount_options} #{mount_device} #{expanded_guest_path}"
 
           # Create the guest path if it doesn't exist
@@ -97,6 +102,14 @@ SCRIPT
             [key, value].compact.join("=")
           end
         end
+
+        def self.display_mfsymlinks_warning(env)
+          d_file = env.data_dir.join("mfsymlinks_warning")
+          if !d_file.exist?
+            FileUtils.touch(d_file.to_path)
+            env.ui.warn(I18n.t("vagrant.actions.vm.smb.mfsymlink_warning"))
+          end
+        end
       end
     end
   end

templates/locales/en.yml

@@ -2410,7 +2410,18 @@ en:
             For more information see:
             RFC5661: https://tools.ietf.org/html/rfc5661#section-2.9.1
             RFC7530: https://tools.ietf.org/html/rfc7530#section-3.1
+        smb:
+          mfsymlink_warning: |-
+            Vagrant is currently configured to mount SMB folders with the 
+            `mfsymlink` option enabled. This is equivalent to adding the 
+            following to your Vagrantfile:
+              
+              config.vm.synced_folder '/host/path', '/guest/path', type: "smb", mount_options: ['mfsymlink']
 
+            This option may be globally disabled with an environment variable:
+
+              VAGRANT_DISABLE_SMBMFSYMLINKS=1
+            
         provision:
           beginning: "Running provisioner: %{provisioner}..."
           disabled_by_config: |-

test/unit/plugins/guests/linux/cap/mount_smb_shared_folder.rb

@@ -8,7 +8,7 @@ describe "VagrantPlugins::GuestLinux::Cap::MountSMBSharedFolder" do
   end
 
   let(:machine) { double("machine", env: env) }
-  let(:env) { double("env", host: host) }
+  let(:env) { double("env", host: host, ui: double("ui"), data_dir: double("data_dir")) }
   let(:host) { double("host") }
   let(:guest) { double("guest") }
   let(:comm) { VagrantTests::DummyCommunicator::Communicator.new(machine) }
@@ -44,6 +44,9 @@ describe "VagrantPlugins::GuestLinux::Cap::MountSMBSharedFolder" do
       allow(comm).to receive(:execute).with(any_args)
       allow(machine).to receive(:guest).and_return(guest)
       allow(guest).to receive(:capability).with(:shell_expand_guest_path, mount_guest_path).and_return(mount_guest_path)
+      allow(ENV).to receive(:[]).with("VAGRANT_DISABLE_SMBMFSYMLINKS").and_return(false)
+      allow(ENV).to receive(:[]).with("GEM_SKIP").and_return(false)
+      allow(cap).to receive(:display_mfsymlinks_warning)
     end
 
     it "generates the expected default mount command" do
@@ -76,13 +79,13 @@ describe "VagrantPlugins::GuestLinux::Cap::MountSMBSharedFolder" do
       cap.mount_smb_shared_folder(machine, mount_name, mount_guest_path, folder_options)
     end
 
-    it "it adds mfsymlinks option by default" do
+    it "adds mfsymlinks option by default" do
       expect(comm).to receive(:sudo).with(/mfsymlinks/, any_args)
       cap.mount_smb_shared_folder(machine, mount_name, mount_guest_path, folder_options)
     end
 
-    it "it does not add mfsymlinks option if env var VAGRANT_DISABLE_SMBMFSYMLINKS exists" do
-      ENV['VAGRANT_DISABLE_SMBMFSYMLINKS'] = "1"
+    it "does not add mfsymlinks option if env var VAGRANT_DISABLE_SMBMFSYMLINKS exists" do
+      expect(ENV).to receive(:[]).with("VAGRANT_DISABLE_SMBMFSYMLINKS").and_return(true)
       expect(comm).not_to receive(:sudo).with(/mfsymlinks/, any_args)
       cap.mount_smb_shared_folder(machine, mount_name, mount_guest_path, folder_options)
     end
@@ -139,4 +142,27 @@ describe "VagrantPlugins::GuestLinux::Cap::MountSMBSharedFolder" do
       end
     end
   end
+
+  describe ".display_mfsymlinks_warning" do
+    let(:gate_file){ double("gate") }
+
+    before do
+      allow(env.data_dir).to receive(:join).and_return(gate_file)
+      allow(gate_file).to receive(:exist?).and_return(false)
+      allow(gate_file).to receive(:to_path).and_return("PATH")
+      allow(FileUtils).to receive(:touch)
+    end
+  
+    it "should output warning message" do
+      expect(env.ui).to receive(:warn).with(/VAGRANT_DISABLE_SMBMFSYMLINKS=1/)
+      cap.display_mfsymlinks_warning(env)
+    end
+
+    it "should not output warning message if gate file exists" do
+      allow(gate_file).to receive(:exist?).and_return(true)
+
+      expect(env.ui).not_to receive(:warn)
+      cap.display_mfsymlinks_warning(env)
+    end
+  end
 end