Use latest tag for the current destination

lib/kamal/cli/app.rb

@@ -284,6 +284,6 @@ class Kamal::Cli::App < Kamal::Cli::Base
     end
 
     def version_or_latest
-      options[:version] || "latest"
+      options[:version] || KAMAL.config.latest_tag
     end
 end

lib/kamal/commands/app.rb

@@ -50,7 +50,7 @@ class Kamal::Commands::App < Kamal::Commands::Base
 
   def current_running_container_id
     pipe \
-      [ shell(chain(latest_image_container_id, latest_container_id)) ],
+      shell(chain(latest_image_container_id, latest_container_id)),
       [ :head, "-1" ]
   end
 
@@ -60,7 +60,7 @@ class Kamal::Commands::App < Kamal::Commands::Base
 
   def current_running_version
     pipe \
-      [ shell(chain(latest_image_container_name, latest_container_name)) ],
+      shell(chain(latest_image_container_name, latest_container_name)),
       [ :head, "-1" ],
       extract_version_from_name
   end

lib/kamal/configuration.rb

@@ -128,7 +128,11 @@ class Kamal::Configuration
   end
 
   def latest_image
-    "#{repository}:#{[ "latest", *destination ].join("-")}"
+    "#{repository}:#{latest_tag}"
+  end
+
+  def latest_tag
+    [ "latest", *destination ].join("-")
   end
 
   def service_with_version

test/integration/docker-compose.yml

@@ -18,7 +18,7 @@ services:
     build:
       context: docker/deployer
     environment:
-      - TEST_ID=${TEST_ID}
+      - TEST_ID=${TEST_ID:-}
     volumes:
       - ../..:/kamal
       - shared:/shared