Allow db:prepare to load schema if database already exists but is empty; also dumps schema after migrations

activerecord/CHANGELOG.md

@@ -1,3 +1,7 @@
+*   Update `db:prepare` task to load schema when an uninitialized database exists, and dump schema after migrations.
+
+    *Ben Sheldon*
+
 *   Fix supporting timezone awareness for `tsrange` and `tstzrange` array columns.
 
     ```ruby

activerecord/lib/active_record/tasks/database_tasks.rb

@@ -192,27 +192,25 @@ module ActiveRecord
           ActiveRecord::Base.establish_connection(db_config)
 
           begin
-            # Skipped when no database
-            migrate
-
-            if ActiveRecord.dump_schema_after_migration
-              dump_schema(db_config, ActiveRecord.schema_format)
-            end
+            database_initialized = ActiveRecord::SchemaMigration.table_exists?
           rescue ActiveRecord::NoDatabaseError
             create(db_config)
+            retry
+          end
 
+          unless database_initialized
             if File.exist?(schema_dump_path(db_config))
               load_schema(
                 db_config,
                 ActiveRecord.schema_format,
                 nil
               )
-            else
-              migrate
             end
-
             seed = true
           end
+
+          migrate
+          dump_schema(db_config) if ActiveRecord.dump_schema_after_migration
         end
 
         ActiveRecord::Base.establish_connection

railties/test/application/rake/dbs_test.rb

@@ -687,35 +687,54 @@ module ApplicationTests
         end
       end
 
-      test "db:prepare setup the database" do
+      test "db:prepare loads schema, runs pending migrations, and updates schema" do
         Dir.chdir(app_path) do
           rails "generate", "model", "book", "title:string"
           output = rails("db:prepare")
           assert_match(/CreateBooks: migrated/, output)
+          assert_match(/create_table "books"/, File.read("db/schema.rb"))
 
           output = rails("db:drop")
           assert_match(/Dropped database/, output)
 
           rails "generate", "model", "recipe", "title:string"
           output = rails("db:prepare")
-          assert_match(/CreateBooks: migrated/, output)
+          assert_no_match(/CreateBooks: migrated/, output) # loaded from schema
           assert_match(/CreateRecipes: migrated/, output)
+
+          schema = File.read("db/schema.rb")
+          assert_match(/create_table "books"/, schema)
+          assert_match(/create_table "recipes"/, schema)
+
+          tables = rails("runner", "p ActiveRecord::Base.connection.tables.sort").strip
+          assert_equal('["ar_internal_metadata", "books", "recipes", "schema_migrations"]', tables)
         end
       end
 
-      test "db:prepare does not touch schema when dumping is disabled" do
+      test "db:prepare loads schema when database exists but is empty" do
+        rails "generate", "model", "book", "title:string"
+        rails("db:prepare", "db:drop", "db:create")
+
+        output = rails("db:prepare")
+        assert_no_match(/CreateBooks: migrated/, output)
+
+        tables = rails("runner", "p ActiveRecord::Base.connection.tables.sort").strip
+        assert_equal('["ar_internal_metadata", "books", "schema_migrations"]', tables)
+      end
+
+      test "db:prepare does not dump schema when dumping is disabled" do
         Dir.chdir(app_path) do
           rails "generate", "model", "book", "title:string"
           rails "db:create", "db:migrate"
 
-          app_file "db/schema.rb", "Not touched"
+          app_file "db/schema.rb", "# Not touched"
           app_file "config/initializers/disable_dumping_schema.rb", <<-RUBY
             Rails.application.config.active_record.dump_schema_after_migration = false
           RUBY
 
           rails "db:prepare"
 
-          assert_equal("Not touched", File.read("db/schema.rb").strip)
+          assert_equal("# Not touched", File.read("db/schema.rb").strip)
         end
       end