Merge pull request #18067 from kamipo/format_datetime_string_according_to_precision

Format the datetime string according to the precision of the datetime field.

Conflicts:
	activerecord/CHANGELOG.md

6 files changed, 225 insertions, 1 deletions

diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md
index d213d6afcf..88eb65aa4c 100644
--- a/activerecord/CHANGELOG.md
+++ b/activerecord/CHANGELOG.md
@@ -1,3 +1,18 @@
+*   Format the datetime string according to the precision of the datetime field.
+
+    Incompatible to rounding behavior between MySQL 5.6 and earlier.
+
+    In 5.5, when you insert `2014-08-17 12:30:00.999999` the fractional part
+    is ignored. In 5.6, it's rounded to `2014-08-17 12:30:01`:
+
+    http://bugs.mysql.com/bug.php?id=68760
+
+    *Ryuta Kamizono*
+
+*   Allow precision option for MySQL datetimes.
+
+    *Ryuta Kamizono*
+
 *   Fixed automatic inverse_of for models nested in module.
 
     *Andrew McCloud*
diff --git a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
index d083e413a5..03d30b5dd0 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
@@ -591,6 +591,13 @@ module ActiveRecord
           when 0x1000000..0xffffffff; 'longtext'
           else raise(ActiveRecordError, "No text type has character length #{limit}")
           end
+        when 'datetime'
+          return super unless precision
+
+          case precision
+            when 0..6; "datetime(#{precision})"
+            else raise(ActiveRecordError, "No datetime type has precision of #{precision}. The allowed range of precision is from 0 to 6.")
+          end
         else
           super
         end
@@ -679,6 +686,11 @@ module ActiveRecord
         m.alias_type %r(year)i,          'integer'
         m.alias_type %r(bit)i,           'binary'
 
+        m.register_type(%r(datetime)i) do |sql_type|
+          precision = extract_precision(sql_type)
+          MysqlDateTime.new(precision: precision)
+        end
+
         m.register_type(%r(enum)i) do |sql_type|
           limit = sql_type[/^enum\((.+)\)/i, 1]
             .split(',').map{|enum| enum.strip.length - 2}.max
@@ -872,6 +884,22 @@ module ActiveRecord
         TableDefinition.new(native_database_types, name, temporary, options, as)
       end
 
+      class MysqlDateTime < Type::DateTime # :nodoc:
+        def type_cast_for_database(value)
+          if value.acts_like?(:time) && value.respond_to?(:usec)
+            result = super.to_s(:db)
+            case precision
+            when 1..6
+              "#{result}.#{sprintf("%0#{precision}d", value.usec / 10 ** (6 - precision))}"
+            else
+              result
+            end
+          else
+            super
+          end
+        end
+      end
+
       class MysqlString < Type::String # :nodoc:
         def type_cast_for_database(value)
           case value
diff --git a/activerecord/test/cases/adapters/mysql/datetime_test.rb b/activerecord/test/cases/adapters/mysql/datetime_test.rb
new file mode 100644
index 0000000000..ae00f4e131
--- /dev/null
+++ b/activerecord/test/cases/adapters/mysql/datetime_test.rb
@@ -0,0 +1,87 @@
+require 'cases/helper'
+
+if mysql_56?
+  class DateTimeTest < ActiveRecord::TestCase
+    self.use_transactional_fixtures = false
+
+    class Foo < ActiveRecord::Base; end
+
+    def test_default_datetime_precision
+      ActiveRecord::Base.connection.create_table(:foos, force: true)
+      ActiveRecord::Base.connection.add_column :foos, :created_at, :datetime
+      ActiveRecord::Base.connection.add_column :foos, :updated_at, :datetime
+      assert_nil activerecord_column_option('foos', 'created_at', 'precision')
+    end
+
+    def test_datetime_data_type_with_precision
+      ActiveRecord::Base.connection.create_table(:foos, force: true)
+      ActiveRecord::Base.connection.add_column :foos, :created_at, :datetime, precision: 1
+      ActiveRecord::Base.connection.add_column :foos, :updated_at, :datetime, precision: 5
+      assert_equal 1, activerecord_column_option('foos', 'created_at', 'precision')
+      assert_equal 5, activerecord_column_option('foos', 'updated_at', 'precision')
+    end
+
+    def test_timestamps_helper_with_custom_precision
+      ActiveRecord::Base.connection.create_table(:foos, force: true) do |t|
+        t.timestamps null: true, precision: 4
+      end
+      assert_equal 4, activerecord_column_option('foos', 'created_at', 'precision')
+      assert_equal 4, activerecord_column_option('foos', 'updated_at', 'precision')
+    end
+
+    def test_passing_precision_to_datetime_does_not_set_limit
+      ActiveRecord::Base.connection.create_table(:foos, force: true) do |t|
+        t.timestamps null: true, precision: 4
+      end
+      assert_nil activerecord_column_option('foos', 'created_at', 'limit')
+      assert_nil activerecord_column_option('foos', 'updated_at', 'limit')
+    end
+
+    def test_invalid_datetime_precision_raises_error
+      assert_raises ActiveRecord::ActiveRecordError do
+        ActiveRecord::Base.connection.create_table(:foos, force: true) do |t|
+          t.timestamps null: true, precision: 7
+        end
+      end
+    end
+
+    def test_mysql_agrees_with_activerecord_about_precision
+      ActiveRecord::Base.connection.create_table(:foos, force: true) do |t|
+        t.timestamps null: true, precision: 4
+      end
+      assert_equal 4, mysql_datetime_precision('foos', 'created_at')
+      assert_equal 4, mysql_datetime_precision('foos', 'updated_at')
+    end
+
+    def test_formatting_datetime_according_to_precision
+      ActiveRecord::Base.connection.create_table(:foos, force: true) do |t|
+        t.datetime :created_at, precision: 0
+        t.datetime :updated_at, precision: 4
+      end
+      date = ::Time.utc(2014, 8, 17, 12, 30, 0, 999999)
+      Foo.create!(created_at: date, updated_at: date)
+      assert foo = Foo.find_by(created_at: date)
+      assert_equal date.to_s, foo.created_at.to_s
+      assert_equal date.to_s, foo.updated_at.to_s
+      assert_equal 000000, foo.created_at.usec
+      assert_equal 999900, foo.updated_at.usec
+    end
+
+    private
+
+    def mysql_datetime_precision(table_name, column_name)
+      results = ActiveRecord::Base.connection.exec_query("SELECT column_name, datetime_precision FROM information_schema.columns WHERE table_name = '#{table_name}'")
+      result = results.find do |result_hash|
+        result_hash["column_name"] == column_name
+      end
+      result && result["datetime_precision"]
+    end
+
+    def activerecord_column_option(tablename, column_name, option)
+      result = ActiveRecord::Base.connection.columns(tablename).find do |column|
+        column.name == column_name
+      end
+      result && result.send(option)
+    end
+  end
+end
diff --git a/activerecord/test/cases/adapters/mysql2/datetime_test.rb b/activerecord/test/cases/adapters/mysql2/datetime_test.rb
new file mode 100644
index 0000000000..ae00f4e131
--- /dev/null
+++ b/activerecord/test/cases/adapters/mysql2/datetime_test.rb
@@ -0,0 +1,87 @@
+require 'cases/helper'
+
+if mysql_56?
+  class DateTimeTest < ActiveRecord::TestCase
+    self.use_transactional_fixtures = false
+
+    class Foo < ActiveRecord::Base; end
+
+    def test_default_datetime_precision
+      ActiveRecord::Base.connection.create_table(:foos, force: true)
+      ActiveRecord::Base.connection.add_column :foos, :created_at, :datetime
+      ActiveRecord::Base.connection.add_column :foos, :updated_at, :datetime
+      assert_nil activerecord_column_option('foos', 'created_at', 'precision')
+    end
+
+    def test_datetime_data_type_with_precision
+      ActiveRecord::Base.connection.create_table(:foos, force: true)
+      ActiveRecord::Base.connection.add_column :foos, :created_at, :datetime, precision: 1
+      ActiveRecord::Base.connection.add_column :foos, :updated_at, :datetime, precision: 5
+      assert_equal 1, activerecord_column_option('foos', 'created_at', 'precision')
+      assert_equal 5, activerecord_column_option('foos', 'updated_at', 'precision')
+    end
+
+    def test_timestamps_helper_with_custom_precision
+      ActiveRecord::Base.connection.create_table(:foos, force: true) do |t|
+        t.timestamps null: true, precision: 4
+      end
+      assert_equal 4, activerecord_column_option('foos', 'created_at', 'precision')
+      assert_equal 4, activerecord_column_option('foos', 'updated_at', 'precision')
+    end
+
+    def test_passing_precision_to_datetime_does_not_set_limit
+      ActiveRecord::Base.connection.create_table(:foos, force: true) do |t|
+        t.timestamps null: true, precision: 4
+      end
+      assert_nil activerecord_column_option('foos', 'created_at', 'limit')
+      assert_nil activerecord_column_option('foos', 'updated_at', 'limit')
+    end
+
+    def test_invalid_datetime_precision_raises_error
+      assert_raises ActiveRecord::ActiveRecordError do
+        ActiveRecord::Base.connection.create_table(:foos, force: true) do |t|
+          t.timestamps null: true, precision: 7
+        end
+      end
+    end
+
+    def test_mysql_agrees_with_activerecord_about_precision
+      ActiveRecord::Base.connection.create_table(:foos, force: true) do |t|
+        t.timestamps null: true, precision: 4
+      end
+      assert_equal 4, mysql_datetime_precision('foos', 'created_at')
+      assert_equal 4, mysql_datetime_precision('foos', 'updated_at')
+    end
+
+    def test_formatting_datetime_according_to_precision
+      ActiveRecord::Base.connection.create_table(:foos, force: true) do |t|
+        t.datetime :created_at, precision: 0
+        t.datetime :updated_at, precision: 4
+      end
+      date = ::Time.utc(2014, 8, 17, 12, 30, 0, 999999)
+      Foo.create!(created_at: date, updated_at: date)
+      assert foo = Foo.find_by(created_at: date)
+      assert_equal date.to_s, foo.created_at.to_s
+      assert_equal date.to_s, foo.updated_at.to_s
+      assert_equal 000000, foo.created_at.usec
+      assert_equal 999900, foo.updated_at.usec
+    end
+
+    private
+
+    def mysql_datetime_precision(table_name, column_name)
+      results = ActiveRecord::Base.connection.exec_query("SELECT column_name, datetime_precision FROM information_schema.columns WHERE table_name = '#{table_name}'")
+      result = results.find do |result_hash|
+        result_hash["column_name"] == column_name
+      end
+      result && result["datetime_precision"]
+    end
+
+    def activerecord_column_option(tablename, column_name, option)
+      result = ActiveRecord::Base.connection.columns(tablename).find do |column|
+        column.name == column_name
+      end
+      result && result.send(option)
+    end
+  end
+end
diff --git a/activerecord/test/cases/schema_dumper_test.rb b/activerecord/test/cases/schema_dumper_test.rb
index a094136766..57b7346503 100644
--- a/activerecord/test/cases/schema_dumper_test.rb
+++ b/activerecord/test/cases/schema_dumper_test.rb
@@ -232,6 +232,13 @@ class SchemaDumperTest < ActiveRecord::TestCase
     end
   end
 
+  if mysql_56?
+    def test_schema_dump_includes_datetime_precision
+      output = standard_dump
+      assert_match %r{t.datetime\s+"written_on",\s+precision: 6$}, output
+    end
+  end
+
   def test_schema_dump_includes_decimal_options
     output = dump_all_table_schema([/^[^n]/])
     assert_match %r{precision: 3,[[:space:]]+scale: 2,[[:space:]]+default: 2.78}, output
diff --git a/activerecord/test/schema/schema.rb b/activerecord/test/schema/schema.rb
index a9c2b1d112..5907d6ef97 100644
--- a/activerecord/test/schema/schema.rb
+++ b/activerecord/test/schema/schema.rb
@@ -726,7 +726,7 @@ ActiveRecord::Schema.define do
     t.string   :author_name
     t.string   :author_email_address
     if mysql_56?
-      t.datetime :written_on, limit: 6
+      t.datetime :written_on, precision: 6
     else
       t.datetime :written_on
     end