Move AbstractAdapter#valid_type? to a class method

since this method only needs access to a constant, and does not
actually need a live connection.

Continue to support instance methods `#valid_type?` and
`#native_database_types`, but both of these methods now forward to a
class method of the same name. (All the concrete adapters now
implement a class method `.native_database_types`.)

This allows code without a connection to check the column type without
leasing a connection.

Author: flavorjones

activerecord/CHANGELOG.md

@@ -1,3 +1,7 @@
+*   Model generator no longer needs a database connection to validate column types.
+
+    *Mike Dalessio*
+
 *   Allow signed ID verifiers to be configurable via `Rails.application.message_verifiers`
 
     Prior to this change, the primary way to configure signed ID verifiers was

activerecord/lib/active_record/connection_adapters/abstract_adapter.rb

@@ -260,7 +260,11 @@ def to_s
       end
 
       def valid_type?(type) # :nodoc:
-        !native_database_types[type].nil?
+        self.class.valid_type?(type)
+      end
+
+      def native_database_types # :nodoc:
+        self.class.native_database_types
       end
 
       # this method must only be called while holding connection pool's mutex
@@ -886,6 +890,10 @@ def extended_type_map(default_timezone:) # :nodoc:
           end
         end
 
+        def valid_type?(type) # :nodoc:
+          !native_database_types[type].nil?
+        end
+
         private
           def initialize_type_map(m)
             register_class_with_limit m, %r(boolean)i,       Type::Boolean

activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb

@@ -81,6 +81,10 @@ def dbconsole(config, options = {})
 
           find_cmd_and_exec(ActiveRecord.database_cli[:mysql], *args)
         end
+
+        def native_database_types # :nodoc:
+          NATIVE_DATABASE_TYPES
+        end
       end
 
       def get_database_version # :nodoc:
@@ -196,10 +200,6 @@ def release_advisory_lock(lock_name) # :nodoc:
         query_value("SELECT RELEASE_LOCK(#{quote(lock_name.to_s)})") == 1
       end
 
-      def native_database_types
-        NATIVE_DATABASE_TYPES
-      end
-
       def index_algorithms
         {
           default: "ALGORITHM = DEFAULT",

activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb

@@ -397,10 +397,6 @@ def discard! # :nodoc:
         @raw_connection = nil
       end
 
-      def native_database_types # :nodoc:
-        self.class.native_database_types
-      end
-
       def self.native_database_types # :nodoc:
         @native_database_types ||= begin
           types = NATIVE_DATABASE_TYPES.dup

activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb

@@ -66,6 +66,10 @@ def dbconsole(config, options = {})
 
           find_cmd_and_exec(ActiveRecord.database_cli[:sqlite], *args)
         end
+
+        def native_database_types # :nodoc:
+          NATIVE_DATABASE_TYPES
+        end
       end
 
       include SQLite3::Quoting
@@ -258,10 +262,6 @@ def supports_index_sort_order?
         true
       end
 
-      def native_database_types # :nodoc:
-        NATIVE_DATABASE_TYPES
-      end
-
       # Returns the current database encoding format as a string, e.g. 'UTF-8'
       def encoding
         any_raw_connection.encoding.to_s

activerecord/test/cases/adapter_test.rb

@@ -48,11 +48,13 @@ def test_create_record_with_pk_as_zero
     def test_valid_column
       @connection.native_database_types.each_key do |type|
         assert @connection.valid_type?(type)
+        assert @connection.class.valid_type?(type)
       end
     end
 
     def test_invalid_column
       assert_not @connection.valid_type?(:foobar)
+      assert_not @connection.class.valid_type?(:foobar)
     end
 
     def test_tables

railties/lib/rails/generators/generated_attribute.rb

@@ -73,7 +73,7 @@ def dangerous_name?(name)
         def valid_type?(type)
           DEFAULT_TYPES.include?(type.to_s) ||
             !defined?(ActiveRecord::Base) ||
-            ActiveRecord::Base.lease_connection.valid_type?(type)
+            ActiveRecord::Base.connection_db_config.adapter_class.valid_type?(type)
         end
 
         def valid_index_type?(index_type)