Restore kamal setup to accessory hosts

lib/kamal/commander/specifics.rb

@@ -43,7 +43,12 @@ def specified_roles
     end
 
     def specified_hosts
-      (specific_hosts || config.all_hosts) \
-        .select { |host| (specific_roles || config.roles).flat_map(&:hosts).include?(host) }
+      specified_hosts = specific_hosts || config.all_hosts
+
+      if (specific_role_hosts = specific_roles&.flat_map(&:hosts)).present?
+        specified_hosts.select { |host| specific_role_hosts.include?(host) }
+      else
+        specified_hosts
+      end
     end
 end

test/commander_test.rb

@@ -150,6 +150,27 @@ class CommanderTest < ActiveSupport::TestCase
     assert_equal [ "1.1.1.2" ], @kamal.proxy_hosts
   end
 
+  test "accessory hosts without filtering" do
+    configure_with(:deploy_with_single_accessory)
+    assert_equal [ "1.1.1.5" ], @kamal.accessory_hosts
+
+    configure_with(:deploy_with_accessories_on_independent_server)
+    assert_equal [ "1.1.1.5", "1.1.1.1", "1.1.1.2" ], @kamal.accessory_hosts
+  end
+
+  test "accessory hosts with role filtering" do
+    configure_with(:deploy_with_single_accessory)
+    @kamal.specific_roles = [ "web" ]
+    assert_equal [], @kamal.accessory_hosts
+
+    configure_with(:deploy_with_accessories_on_independent_server)
+    @kamal.specific_roles = [ "web" ]
+    assert_equal [ "1.1.1.1", "1.1.1.2" ], @kamal.accessory_hosts
+
+    @kamal.specific_roles = [ "workers" ]
+    assert_equal [], @kamal.accessory_hosts
+  end
+
   private
     def configure_with(variant)
       @kamal = Kamal::Commander.new.tap do |kamal|

test/fixtures/deploy_with_accessories_on_independent_server.yml

@@ -0,0 +1,38 @@
+service: app
+image: dhh/app
+servers:
+  web:
+    - "1.1.1.1"
+    - "1.1.1.2"
+  workers:
+    - "1.1.1.3"
+    - "1.1.1.4"
+registry:
+  username: user
+  password: pw
+builder:
+  arch: amd64
+
+accessories:
+  mysql:
+    image: mysql:5.7
+    host: 1.1.1.5
+    port: 3306
+    env:
+      clear:
+        MYSQL_ROOT_HOST: '%'
+      secret:
+        - MYSQL_ROOT_PASSWORD
+    files:
+      - test/fixtures/files/my.cnf:/etc/mysql/my.cnf
+    directories:
+      - data:/var/lib/mysql
+  redis:
+    image: redis:latest
+    roles:
+      - web
+    port: 6379
+    directories:
+      - data:/data
+
+readiness_delay: 0

test/fixtures/deploy_with_single_accessory.yml

@@ -0,0 +1,29 @@
+service: app
+image: dhh/app
+servers:
+  web:
+    - "1.1.1.1"
+    - "1.1.1.2"
+  workers:
+    - "1.1.1.3"
+    - "1.1.1.4"
+registry:
+  username: user
+  password: pw
+builder:
+  arch: amd64
+
+accessories:
+  mysql:
+    image: mysql:5.7
+    host: 1.1.1.5
+    port: 3306
+    env:
+      clear:
+        MYSQL_ROOT_HOST: '%'
+      secret:
+        - MYSQL_ROOT_PASSWORD
+    files:
+      - test/fixtures/files/my.cnf:/etc/mysql/my.cnf
+    directories:
+      - data:/var/lib/mysql