Dump schema only for a specific db for rollback/up/down tasks for multiple dbs

activerecord/lib/active_record/railties/databases.rake

@@ -204,7 +204,7 @@ db_namespace = namespace :db do
             conn.migration_context.run(:up, ActiveRecord::Tasks::DatabaseTasks.target_version)
           end
 
-          db_namespace["_dump"].invoke
+          db_namespace["_dump:#{name}"].invoke
         end
       end
     end
@@ -235,7 +235,7 @@ db_namespace = namespace :db do
             conn.migration_context.run(:down, ActiveRecord::Tasks::DatabaseTasks.target_version)
           end
 
-          db_namespace["_dump"].invoke
+          db_namespace["_dump:#{name}"].invoke
         end
       end
     end
@@ -269,7 +269,7 @@ db_namespace = namespace :db do
           conn.migration_context.rollback(step)
         end
 
-        db_namespace["_dump"].invoke
+        db_namespace["_dump:#{name}"].invoke
       end
     end
   end

railties/test/application/rake/multi_dbs_test.rb

@@ -692,6 +692,28 @@ class TwoMigration < ActiveRecord::Migration::Current
         db_up_and_down "02", "animals"
       end
 
+      test "db:migrate:down:namespace and db:migrate:up:namespace dumps schema only for specific database" do
+        require "#{app_path}/config/environment"
+
+        app_file "db/migrate/01_one_migration.rb", <<-MIGRATION
+          class OneMigration < ActiveRecord::Migration::Current
+          end
+        MIGRATION
+
+        app_file "db/animals_migrate/02_two_migration.rb", <<-MIGRATION
+          class TwoMigration < ActiveRecord::Migration::Current
+          end
+        MIGRATION
+
+        Dir.chdir(app_path) do
+          rails("db:migrate:up:primary", "VERSION=01")
+          rails("db:migrate:down:primary", "VERSION=01")
+
+          assert File.exist?("db/schema.rb"), "should dump schema for primary database"
+          assert_not File.exist?("db/animals_schema.rb"), "should not dump schema for animals database"
+        end
+      end
+
       test "db:migrate:redo raises in a multi-db application" do
         require "#{app_path}/config/environment"
         db_migrate_redo
@@ -742,6 +764,20 @@ class TwoMigration < ActiveRecord::Migration::Current
         db_migrate_and_rollback "animals"
       end
 
+      test "db:rollback:namespace dumps schema only for specific database" do
+        Dir.chdir(app_path) do
+          rails "generate", "model", "book", "title:string"
+          rails "generate", "model", "dog", "name:string", "--database animals"
+          rails "db:migrate"
+          File.delete("db/animals_schema.rb")
+
+          rails "db:rollback:primary"
+
+          assert File.exist?("db/schema.rb"), "should dump schema for primary database"
+          assert_not File.exist?("db/animals_schema.rb"), "should not dump schema for animals database"
+        end
+      end
+
       test "db:migrate:status works on all databases" do
         require "#{app_path}/config/environment"
         db_migrate_and_migrate_status