Merge pull request rails#49988 from skipkayhil/hm-fix-db-change-no-docker

Fix running db:system:change with no Dockerfile

Author: jonathanhefner

railties/CHANGELOG.md

@@ -1,3 +1,7 @@
+*   Fix running `db:system:change` when app has no Dockerfile.
+
+    *Hartley McGuire*
+
 *   In Action Mailer previews, list inline attachments separately from normal
     attachments. For example, attachments that were previously listed like
 

railties/lib/rails/generators/rails/db/system/change/change_generator.rb

@@ -41,6 +41,9 @@ def edit_gemfile
           end
 
           def edit_dockerfile
+            dockerfile_path = File.expand_path("Dockerfile", destination_root)
+            return unless File.exist?(dockerfile_path)
+
             build_name = docker_for_database_build
             deploy_name = docker_for_database_deploy
             if build_name

railties/test/commands/db_system_change_test.rb

@@ -60,6 +60,14 @@ class Rails::Command::DbSystemChangeTest < ActiveSupport::TestCase
     assert_match "gsub  Gemfile", output
   end
 
+  test "change works with no Dockerfile" do
+    remove_file("Dockerfile")
+
+    output = change_database(to: "sqlite3")
+
+    assert_match "gsub  Gemfile", output
+  end
+
   private
     def change_database(to:, **options)
       args = ["--to", to]