Fixes #11218: Update apk cache when installing rsync (#11220)

This ensures that rsync can be installed on an Alpine Linux machine where the
apk cache may not be current.

Display a warning if the vagrant-alpine plugin is installed, since Alpine guest
support has been merged into Vagrant core.

plugins/guests/alpine/cap/rsync.rb

@@ -8,7 +8,7 @@ module VagrantPlugins
 
         def self.rsync_install(machine)
           machine.communicate.tap do |comm|
-            comm.sudo('apk add rsync')
+            comm.sudo('apk add --update-cache rsync')
           end
         end
       end

plugins/guests/alpine/plugin.rb

@@ -45,6 +45,22 @@ module VagrantPlugins
         require_relative 'cap/smb'
         Cap::SMB
       end
+
+      def self.check_community_plugin
+        plugins = Vagrant::Plugin::Manager.instance.installed_plugins
+        if plugins.keys.include?("vagrant-alpine")
+          $stderr.puts <<-EOF
+WARNING: Vagrant has detected the `vagrant-alpine` plugin. This plugin's
+functionality has been merged into the main Vagrant project and should be
+considered deprecated. To uninstall the plugin, run the command shown below:
+
+  vagrant plugin uninstall vagrant-alpine
+
+EOF
+        end
+      end
+
+      self.check_community_plugin
     end
   end
 end

test/unit/plugins/guests/alpine/cap/rsync_test.rb

@@ -16,9 +16,9 @@ describe 'VagrantPlugins::GuestAlpine::Cap::RSync' do
         VagrantPlugins::GuestAlpine::Plugin.components.guest_capabilities[:alpine].get(:rsync_install)
     end
 
-    it 'should install rsync' do
+    it 'should install rsync with --update-cache flag' do
         # communicator.should_receive(:sudo).with('apk add rsync')
-        expect(communicator).to receive(:sudo).with('apk add rsync')
+        expect(communicator).to receive(:sudo).with('apk add --update-cache rsync')
         allow_message_expectations_on_nil
         described_class.rsync_install(machine)
     end

test/unit/plugins/guests/alpine/plugin_test.rb

@@ -0,0 +1,32 @@
+require File.expand_path("../../../../base", __FILE__)
+
+
+describe VagrantPlugins::GuestAlpine::Plugin do
+  let(:manager) { double("manager") }
+
+  before do
+    allow(Vagrant::Plugin::Manager).to receive(:instance).and_return(manager)
+  end
+
+  context "when vagrant-alpine plugin is not installed" do
+    before do
+      allow(manager).to receive(:installed_plugins).and_return({})
+    end
+
+    it "should not display a warning" do
+      expect($stderr).to_not receive(:puts)
+      VagrantPlugins::GuestAlpine::Plugin.check_community_plugin
+    end
+  end
+
+  context "when vagrant-alpine plugin is installed" do
+    before do
+      allow(manager).to receive(:installed_plugins).and_return({ "vagrant-alpine" => {} })
+    end
+
+    it "should display a warning" do
+      expect($stderr).to receive(:puts).with(/vagrant plugin uninstall vagrant-alpine/)
+      VagrantPlugins::GuestAlpine::Plugin.check_community_plugin
+    end
+  end
+end