Merge pull request rails#52700 from ngan/fix-db-prepare-schema-dump

Dump schema only once after database prepare

Author: rafaelfranca

activerecord/lib/active_record/tasks/database_tasks.rb

@@ -175,6 +175,7 @@ def create_current(environment = env, name = nil)
 
       def prepare_all
         seed = false
+        dump_db_configs = []
 
         each_current_configuration(env) do |db_config|
           with_temporary_pool(db_config) do
@@ -197,15 +198,23 @@ def prepare_all
 
         each_current_environment(env) do |environment|
           db_configs_with_versions(environment).sort.each do |version, db_configs|
+            dump_db_configs |= db_configs
+
             db_configs.each do |db_config|
               with_temporary_pool(db_config) do
                 migrate(version)
-                dump_schema(db_config) if ActiveRecord.dump_schema_after_migration
               end
             end
           end
         end
 
+        # Dump schema for databases that were migrated.
+        if ActiveRecord.dump_schema_after_migration
+          dump_db_configs.each do |db_config|
+            dump_schema(db_config)
+          end
+        end
+
         load_seed if seed
       end
 

railties/test/application/rake/multi_dbs_test.rb

@@ -556,7 +556,6 @@ class ThreeMigration < ActiveRecord::Migration::Current
           end
         MIGRATION
 
-
         Dir.chdir(app_path) do
           rails "db:migrate:up:primary", "VERSION=01_one_migration.rb"
           rails "db:migrate:up:primary", "VERSION=03_three_migration.rb"
@@ -595,6 +594,46 @@ class ThreeMigration < ActiveRecord::Migration::Current
         end
       end
 
+      test "db:prepare only dumps schema for migrated databases" 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
+
+        primary_mtime = nil
+        animals_mtime = nil
+
+        Dir.chdir(app_path) do
+          # Run the first two migrations to get the schema files.
+          rails "db:prepare"
+
+          assert File.exist?("db/schema.rb")
+          assert File.exist?("db/animals_schema.rb")
+
+          primary_mtime = File.mtime("db/schema.rb")
+          animals_mtime = File.mtime("db/animals_schema.rb")
+        end
+
+        app_file "db/animals_migrate/03_three_migration.rb", <<-MIGRATION
+          class ThreeMigration < ActiveRecord::Migration::Current
+          end
+        MIGRATION
+
+        Dir.chdir(app_path) do
+          # Run the new migration and assert that only the animals schema was updated.
+          rails "db:prepare"
+
+          assert_equal primary_mtime, File.mtime("db/schema.rb")
+          assert_not_equal animals_mtime, File.mtime("db/animals_schema.rb")
+        end
+      end
+
       test "migrations in different directories can have the same timestamp" do
         require "#{app_path}/config/environment"
         app_file "db/migrate/01_one_migration.rb", <<-MIGRATION