Print message if update is unavailable

lib/foreman_maintain/cli/update_command.rb

@@ -19,16 +19,42 @@ def update_runner
         update_runner
       end
 
+      def try_update
+        if update_runner.available?
+          yield
+        else
+          instance = ForemanMaintain.detector.feature(:instance)
+          msg = <<~BANNER
+
+            This version of #{ForemanMaintain.command_name} only supports #{instance.target_version},
+            but the installed version of #{instance.product_name} is #{instance.current_major_version}.
+
+            Therefore the update command is not available right now.
+
+            Please install a version of #{ForemanMaintain.command_name} that supports #{instance.current_major_version}
+            or perform an upgrade to #{instance.target_version} using the upgrade command.
+          BANNER
+
+          puts msg
+          ForemanMaintain::UpdateRunner::WARNING_EXIT_CODE
+        end
+      end
+
       subcommand 'check', 'Run pre-update checks before updating' do
         interactive_option
         disable_self_update_option
 
         def execute
           ForemanMaintain.validate_downstream_packages
           ForemanMaintain.perform_self_upgrade unless disable_self_update?
-          runner = update_runner
-          runner.run_phase(:pre_update_checks)
-          exit runner.exit_code
+
+          exit_code = try_update do
+            runner = update_runner
+            runner.run_phase(:pre_update_checks)
+            runner.exit_code
+          end
+
+          exit exit_code
         end
       end
 
@@ -39,10 +65,15 @@ def execute
         def execute
           ForemanMaintain.validate_downstream_packages
           ForemanMaintain.perform_self_upgrade unless disable_self_update?
-          runner = update_runner
-          runner.run
-          runner.save
-          exit runner.exit_code
+
+          exit_code = try_update do
+            runner = update_runner
+            runner.run
+            runner.save
+            runner.exit_code
+          end
+
+          exit exit_code
         end
       end
     end

lib/foreman_maintain/update_runner.rb

@@ -18,6 +18,12 @@ def initialize(reporter, options = {})
       self.phase = :pre_update_checks
     end
 
+    def available?
+      condition = { :tags => [:update_scenario, :pre_update_checks] }
+      matching_scenarios = find_scenarios(condition)
+      !matching_scenarios.empty?
+    end
+
     def find_scenario(phase)
       return @scenario_cache[phase] if @scenario_cache.key?(phase)
 

test/lib/cli/update_command_test.rb

@@ -76,6 +76,7 @@ def foreman_maintain_update_unavailable
       it 'runs the update checks when update is not available for foreman-maintain' do
         foreman_maintain_update_unavailable
         UpdateRunner.any_instance.expects(:run_phase).with(:pre_update_checks)
+        UpdateRunner.any_instance.expects(:available?).returns(true)
         assert_cmd <<~OUTPUT
           Checking for new version of rubygem-foreman_maintain...
           Nothing to update, can't find new version of rubygem-foreman_maintain.
@@ -86,8 +87,29 @@ def foreman_maintain_update_unavailable
         foreman_maintain_update_available
         command << '--disable-self-update'
         UpdateRunner.any_instance.expects(:run_phase).with(:pre_update_checks)
+        UpdateRunner.any_instance.expects(:available?).returns(true)
         run_cmd
       end
+
+      it 'throws an error message if no update is available' do
+        foreman_maintain_update_unavailable
+        UpdateRunner.any_instance.expects(:available?).twice.returns(false)
+
+        assert_cmd <<~OUTPUT
+          Checking for new version of rubygem-foreman_maintain...
+          Nothing to update, can't find new version of rubygem-foreman_maintain.
+
+          This version of foreman-maintain only supports 3.15.0,
+          but the installed version of FakeyFakeFake is 3.14.
+
+          Therefore the update command is not available right now.
+
+          Please install a version of foreman-maintain that supports 3.14
+          or perform an upgrade to 3.15.0 using the upgrade command.
+        OUTPUT
+
+        run_cmd([])
+      end
     end
 
     describe 'run' do
@@ -109,6 +131,7 @@ def foreman_maintain_update_unavailable
 
       it 'runs the update when update is not available for foreman-maintain' do
         foreman_maintain_update_unavailable
+        UpdateRunner.any_instance.expects(:available?).returns(true)
         UpdateRunner.any_instance.expects(:run)
         assert_cmd <<~OUTPUT
           Checking for new version of rubygem-foreman_maintain...
@@ -119,9 +142,30 @@ def foreman_maintain_update_unavailable
       it 'skip self update and runs the full update for version' do
         command << '--disable-self-update'
         UpdateRunner.any_instance.expects(:run)
+        UpdateRunner.any_instance.expects(:available?).returns(true)
         run_cmd
       end
 
+      it 'throws an error message if no update is available' do
+        foreman_maintain_update_unavailable
+        UpdateRunner.any_instance.expects(:available?).twice.returns(false)
+
+        assert_cmd <<~OUTPUT
+          Checking for new version of rubygem-foreman_maintain...
+          Nothing to update, can't find new version of rubygem-foreman_maintain.
+
+          This version of foreman-maintain only supports 3.15.0,
+          but the installed version of FakeyFakeFake is 3.14.
+
+          Therefore the update command is not available right now.
+
+          Please install a version of foreman-maintain that supports 3.14
+          or perform an upgrade to 3.15.0 using the upgrade command.
+        OUTPUT
+
+        run_cmd([])
+      end
+
       it 'runs the self update when update available for rubygem-foreman_maintain' do
         foreman_maintain_update_available
         assert_cmd <<~OUTPUT

test/lib/support/definitions/features/fake_instance.rb

@@ -19,6 +19,10 @@ def current_version
     '3.14.2'
   end
 
+  def target_version
+    '3.15.0'
+  end
+
   def current_major_version
     current_version.to_s[/^\d+\.\d+/]
   end