Abstract high precision timestamp in rb schema

activerecord/lib/active_record/connection_adapters/abstract/schema_dumper.rb

@@ -96,7 +96,13 @@ def schema_default(column)
         end
 
         def schema_expression(column)
-          "-> { #{column.default_function.inspect} }" if column.default_function
+          return unless column.default_function
+
+          if column.default_function == @connection.high_precision_current_timestamp
+            "-> { high_precision_current_timestamp } "
+          else
+            "-> { #{column.default_function.inspect} }"
+          end
         end
 
         def schema_collation(column)

activerecord/test/cases/schema_dumper_test.rb

@@ -931,12 +931,14 @@ class SchemaDumperDefaultsTest < ActiveRecord::TestCase
 
   setup do
     @connection = ActiveRecord::Base.lease_connection
+    high_precision_timestamp_function = @connection.high_precision_current_timestamp
     @connection.create_table :dump_defaults, force: true do |t|
       t.string   :string_with_default,   default: "Hello!"
       t.date     :date_with_default,     default: "2014-06-05"
       t.datetime :datetime_with_default, default: "2014-06-05 07:17:04"
       t.time     :time_with_default,     default: "07:17:04"
       t.decimal  :decimal_with_default,  default: "1234567890.0123456789", precision: 20, scale: 10
+      t.timestamp :high_precision_published_at, default: -> { high_precision_timestamp_function }
 
       if supports_text_column_with_default?
         t.text :text_with_default, default: "John' Doe"
@@ -965,6 +967,11 @@ class SchemaDumperDefaultsTest < ActiveRecord::TestCase
     @connection.drop_table "dump_defaults", if_exists: true
   end
 
+  def test_schema_dump_abstracts_high_precision_current_timestamp
+    output = dump_table_schema("dump_defaults")
+    assert_match %r{t\.datetime\s+"high_precision_published_at",\s+default: -> \{ high_precision_current_timestamp \}}, output
+  end
+
   def test_schema_dump_defaults_with_universally_supported_types
     output = dump_table_schema("dump_defaults")
 

activerecord/test/schema/schema.rb

@@ -61,6 +61,7 @@
     t.integer :wheels_count, default: 0, null: false
     t.datetime :wheels_owned_at
     t.timestamp :manufactured_at, default: -> { "CURRENT_TIMESTAMP" }
+    t.datetime :manufactured_precicely_at, default: -> { high_precision_current_timestamp }
   end
 
   create_table :articles, force: true do |t|