Issue #2826404 by mpdonadio, Jo Fitzgerald, jhedstrom, larowlan: Create...

Issue #2826404 by mpdonadio, Jo Fitzgerald, jhedstrom, larowlan: Create DateTimeItemInterface and deprecate global constants in datetime.module

core/modules/datetime/datetime.module

@@ -9,16 +9,34 @@
 
 /**
  * Defines the timezone that dates should be stored in.
+ *
+ * @deprecated in Drupal 8.5.x and will be removed before Drupal 9.0.x. Use
+ * \Drupal\datetime\Plugin\Field\FieldType\DateTimeItemInterface::STORAGE_TIMEZONE
+ * instead.
+ *
+ * @see https://www.drupal.org/node/2912980
  */
 const DATETIME_STORAGE_TIMEZONE = 'UTC';
 
 /**
  * Defines the format that date and time should be stored in.
+ *
+ * @deprecated in Drupal 8.5.x and will be removed before Drupal 9.0.x. Use
+ * \Drupal\datetime\Plugin\Field\FieldType\DateTimeItemInterface::DATETIME_STORAGE_FORMAT
+ * instead.
+ *
+ * @see https://www.drupal.org/node/2912980
  */
 const DATETIME_DATETIME_STORAGE_FORMAT = 'Y-m-d\TH:i:s';
 
 /**
  * Defines the format that dates should be stored in.
+ *
+ * @deprecated in Drupal 8.5.x and will be removed before Drupal 9.0.x. Use
+ * \Drupal\datetime\Plugin\Field\FieldType\DateTimeItemInterface::DATE_STORAGE_FORMAT
+ * instead.
+ *
+ * @see https://www.drupal.org/node/2912980
  */
 const DATETIME_DATE_STORAGE_FORMAT = 'Y-m-d';
 

core/modules/datetime/src/DateTimeComputed.php

@@ -7,6 +7,7 @@
 use Drupal\Core\TypedData\DataDefinitionInterface;
 use Drupal\Core\TypedData\TypedDataInterface;
 use Drupal\Core\TypedData\TypedData;
+use Drupal\datetime\Plugin\Field\FieldType\DateTimeItemInterface;
 
 /**
  * A computed property for dates of date time field items.
@@ -46,9 +47,9 @@ public function getValue($langcode = NULL) {
     $value = $item->{($this->definition->getSetting('date source'))};
 
     $datetime_type = $item->getFieldDefinition()->getSetting('datetime_type');
-    $storage_format = $datetime_type === DateTimeItem::DATETIME_TYPE_DATE ? DATETIME_DATE_STORAGE_FORMAT : DATETIME_DATETIME_STORAGE_FORMAT;
+    $storage_format = $datetime_type === DateTimeItem::DATETIME_TYPE_DATE ? DateTimeItemInterface::DATE_STORAGE_FORMAT : DateTimeItemInterface::DATETIME_STORAGE_FORMAT;
     try {
-      $date = DrupalDateTime::createFromFormat($storage_format, $value, DATETIME_STORAGE_TIMEZONE);
+      $date = DrupalDateTime::createFromFormat($storage_format, $value, DateTimeItemInterface::STORAGE_TIMEZONE);
       if ($date instanceof DrupalDateTime && !$date->hasErrors()) {
         $this->date = $date;
         // If the format did not include an explicit time portion, then the

core/modules/datetime/src/Plugin/Field/FieldFormatter/DateTimeCustomFormatter.php

@@ -5,6 +5,7 @@
 use Drupal\Core\Datetime\DrupalDateTime;
 use Drupal\Core\Field\FieldItemListInterface;
 use Drupal\Core\Form\FormStateInterface;
+use Drupal\datetime\Plugin\Field\FieldType\DateTimeItemInterface;
 
 /**
  * Plugin implementation of the 'Custom' formatter for 'datetime' fields.
@@ -24,7 +25,7 @@ class DateTimeCustomFormatter extends DateTimeFormatterBase {
    */
   public static function defaultSettings() {
     return [
-      'date_format' => DATETIME_DATETIME_STORAGE_FORMAT,
+      'date_format' => DateTimeItemInterface::DATETIME_STORAGE_FORMAT,
     ] + parent::defaultSettings();
   }
 

core/modules/datetime/src/Plugin/Field/FieldFormatter/DateTimeFormatterBase.php

@@ -11,6 +11,7 @@
 use Drupal\Core\Form\FormStateInterface;
 use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
 use Drupal\datetime\Plugin\Field\FieldType\DateTimeItem;
+use Drupal\datetime\Plugin\Field\FieldType\DateTimeItemInterface;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 
 /**
@@ -167,7 +168,7 @@ public function viewElements(FieldItemListInterface $items, $langcode) {
   protected function setTimeZone(DrupalDateTime $date) {
     if ($this->getFieldSetting('datetime_type') === DateTimeItem::DATETIME_TYPE_DATE) {
       // A date without time has no timezone conversion.
-      $timezone = DATETIME_STORAGE_TIMEZONE;
+      $timezone = DateTimeItemInterface::STORAGE_TIMEZONE;
     }
     else {
       $timezone = drupal_get_user_timezone();

core/modules/datetime/src/Plugin/Field/FieldFormatter/DateTimePlainFormatter.php

@@ -4,6 +4,7 @@
 
 use Drupal\Core\Field\FieldItemListInterface;
 use Drupal\datetime\Plugin\Field\FieldType\DateTimeItem;
+use Drupal\datetime\Plugin\Field\FieldType\DateTimeItemInterface;
 
 /**
  * Plugin implementation of the 'Plain' formatter for 'datetime' fields.
@@ -40,7 +41,7 @@ public function viewElements(FieldItemListInterface $items, $langcode) {
    * {@inheritdoc}
    */
   protected function formatDate($date) {
-    $format = $this->getFieldSetting('datetime_type') == DateTimeItem::DATETIME_TYPE_DATE ? DATETIME_DATE_STORAGE_FORMAT : DATETIME_DATETIME_STORAGE_FORMAT;
+    $format = $this->getFieldSetting('datetime_type') == DateTimeItem::DATETIME_TYPE_DATE ? DateTimeItemInterface::DATE_STORAGE_FORMAT : DateTimeItemInterface::DATETIME_STORAGE_FORMAT;
     $timezone = $this->getSetting('timezone_override');
     return $this->dateFormatter->format($date->getTimestamp(), 'custom', $format, $timezone != '' ? $timezone : NULL);
   }

core/modules/datetime/src/Plugin/Field/FieldType/DateTimeFieldItemList.php

@@ -96,13 +96,13 @@ public static function processDefaultValue($default_value, FieldableEntityInterf
         // A default date only value should be in the format used for date
         // storage but in the user's local timezone.
         $date = new DrupalDateTime($default_value[0]['default_date'], drupal_get_user_timezone());
-        $format = DATETIME_DATE_STORAGE_FORMAT;
+        $format = DateTimeItemInterface::DATE_STORAGE_FORMAT;
       }
       else {
         // A default date+time value should be in the format and timezone used
         // for date storage.
-        $date = new DrupalDateTime($default_value[0]['default_date'], DATETIME_STORAGE_TIMEZONE);
-        $format = DATETIME_DATETIME_STORAGE_FORMAT;
+        $date = new DrupalDateTime($default_value[0]['default_date'], DateTimeItemInterface::STORAGE_TIMEZONE);
+        $format = DateTimeItemInterface::DATETIME_STORAGE_FORMAT;
       }
       $value = $date->format($format);
       // We only provide a default value for the first item, as do all fields.

core/modules/datetime/src/Plugin/Field/FieldType/DateTimeItem.php

@@ -21,7 +21,7 @@
  *   constraints = {"DateTimeFormat" = {}}
  * )
  */
-class DateTimeItem extends FieldItemBase {
+class DateTimeItem extends FieldItemBase implements DateTimeItemInterface {
 
   /**
    * {@inheritdoc}
@@ -109,10 +109,10 @@ public static function generateSampleValue(FieldDefinitionInterface $field_defin
     // type.
     $timestamp = REQUEST_TIME - mt_rand(0, 86400 * 365);
     if ($type == DateTimeItem::DATETIME_TYPE_DATE) {
-      $values['value'] = gmdate(DATETIME_DATE_STORAGE_FORMAT, $timestamp);
+      $values['value'] = gmdate(static::DATE_STORAGE_FORMAT, $timestamp);
     }
     else {
-      $values['value'] = gmdate(DATETIME_DATETIME_STORAGE_FORMAT, $timestamp);
+      $values['value'] = gmdate(static::DATETIME_STORAGE_FORMAT, $timestamp);
     }
     return $values;
   }

core/modules/datetime/src/Plugin/Field/FieldType/DateTimeItemInterface.php

+<?php
+
+namespace Drupal\datetime\Plugin\Field\FieldType;
+
+/**
+ * Interface definition for Datetime items.
+ */
+interface DateTimeItemInterface {
+
+  /**
+   * Defines the timezone that dates should be stored in.
+   */
+  const STORAGE_TIMEZONE = 'UTC';
+
+  /**
+   * Defines the format that date and time should be stored in.
+   */
+  const DATETIME_STORAGE_FORMAT = 'Y-m-d\TH:i:s';
+
+  /**
+   * Defines the format that dates should be stored in.
+   */
+  const DATE_STORAGE_FORMAT = 'Y-m-d';
+
+}

core/modules/datetime/src/Plugin/Field/FieldWidget/DateTimeWidgetBase.php

@@ -7,6 +7,7 @@
 use Drupal\Core\Field\WidgetBase;
 use Drupal\Core\Form\FormStateInterface;
 use Drupal\datetime\Plugin\Field\FieldType\DateTimeItem;
+use Drupal\datetime\Plugin\Field\FieldType\DateTimeItemInterface;
 
 /**
  * Base class for the 'datetime_*' widgets.
@@ -28,7 +29,7 @@ public function formElement(FieldItemListInterface $items, $delta, array $elemen
     if ($this->getFieldSetting('datetime_type') == DateTimeItem::DATETIME_TYPE_DATE) {
       // A date-only field should have no timezone conversion performed, so
       // use the same timezone as for storage.
-      $element['value']['#date_timezone'] = DATETIME_STORAGE_TIMEZONE;
+      $element['value']['#date_timezone'] = DateTimeItemInterface::STORAGE_TIMEZONE;
     }
 
     if ($items[$delta]->date) {
@@ -54,15 +55,15 @@ public function massageFormValues(array $values, array $form, FormStateInterface
         $date = $item['value'];
         switch ($this->getFieldSetting('datetime_type')) {
           case DateTimeItem::DATETIME_TYPE_DATE:
-            $format = DATETIME_DATE_STORAGE_FORMAT;
+            $format = DateTimeItemInterface::DATE_STORAGE_FORMAT;
             break;
 
           default:
-            $format = DATETIME_DATETIME_STORAGE_FORMAT;
+            $format = DateTimeItemInterface::DATETIME_STORAGE_FORMAT;
             break;
         }
         // Adjust the date for storage.
-        $date->setTimezone(new \DateTimezone(DATETIME_STORAGE_TIMEZONE));
+        $date->setTimezone(new \DateTimezone(DateTimeItemInterface::STORAGE_TIMEZONE));
         $item['value'] = $date->format($format);
       }
     }

core/modules/datetime/src/Plugin/Validation/Constraint/DateTimeFormatConstraintValidator.php

@@ -4,6 +4,7 @@
 
 use Drupal\Component\Datetime\DateTimePlus;
 use Drupal\datetime\Plugin\Field\FieldType\DateTimeItem;
+use Drupal\datetime\Plugin\Field\FieldType\DateTimeItemInterface;
 use Symfony\Component\Validator\Constraint;
 use Symfony\Component\Validator\ConstraintValidator;
 
@@ -24,10 +25,10 @@ public function validate($item, Constraint $constraint) {
       }
       else {
         $datetime_type = $item->getFieldDefinition()->getSetting('datetime_type');
-        $format = $datetime_type === DateTimeItem::DATETIME_TYPE_DATE ? DATETIME_DATE_STORAGE_FORMAT : DATETIME_DATETIME_STORAGE_FORMAT;
+        $format = $datetime_type === DateTimeItem::DATETIME_TYPE_DATE ? DateTimeItemInterface::DATE_STORAGE_FORMAT : DateTimeItemInterface::DATETIME_STORAGE_FORMAT;
         $date = NULL;
         try {
-          $date = DateTimePlus::createFromFormat($format, $value, new \DateTimeZone(DATETIME_STORAGE_TIMEZONE));
+          $date = DateTimePlus::createFromFormat($format, $value, new \DateTimeZone(DateTimeItemInterface::STORAGE_TIMEZONE));
         }
         catch (\InvalidArgumentException $e) {
           $this->context->addViolation($constraint->badFormat, [

core/modules/datetime/src/Plugin/views/filter/Date.php

@@ -5,6 +5,7 @@
 use Drupal\Core\Datetime\DateFormatterInterface;
 use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
 use Drupal\datetime\Plugin\Field\FieldType\DateTimeItem;
+use Drupal\datetime\Plugin\Field\FieldType\DateTimeItemInterface;
 use Drupal\views\FieldAPIHandlerTrait;
 use Drupal\views\Plugin\views\filter\Date as NumericDate;
 use Symfony\Component\DependencyInjection\ContainerInterface;
@@ -38,7 +39,7 @@ class Date extends NumericDate implements ContainerFactoryPluginInterface {
    *
    * @see \Drupal\views\Plugin\views\query\Sql::getDateFormat()
    */
-  protected $dateFormat = DATETIME_DATETIME_STORAGE_FORMAT;
+  protected $dateFormat = DateTimeItemInterface::DATETIME_STORAGE_FORMAT;
 
   /**
    * The request stack used to determin current time.
@@ -69,7 +70,7 @@ public function __construct(array $configuration, $plugin_id, $plugin_definition
     // Date format depends on field storage format.
     $definition = $this->getFieldStorageDefinition();
     if ($definition->getSetting('datetime_type') === DateTimeItem::DATETIME_TYPE_DATE) {
-      $this->dateFormat = DATETIME_DATE_STORAGE_FORMAT;
+      $this->dateFormat = DateTimeItemInterface::DATE_STORAGE_FORMAT;
     }
   }
 
@@ -99,8 +100,8 @@ protected function opBetween($field) {
 
     // Convert to ISO format and format for query. UTC timezone is used since
     // dates are stored in UTC.
-    $a = $this->query->getDateFormat("'" . $this->dateFormatter->format($a, 'custom', DATETIME_DATETIME_STORAGE_FORMAT, DATETIME_STORAGE_TIMEZONE) . "'", $this->dateFormat, TRUE);
-    $b = $this->query->getDateFormat("'" . $this->dateFormatter->format($b, 'custom', DATETIME_DATETIME_STORAGE_FORMAT, DATETIME_STORAGE_TIMEZONE) . "'", $this->dateFormat, TRUE);
+    $a = $this->query->getDateFormat("'" . $this->dateFormatter->format($a, 'custom', DateTimeItemInterface::DATETIME_STORAGE_FORMAT, DateTimeItemInterface::STORAGE_TIMEZONE) . "'", $this->dateFormat, TRUE);
+    $b = $this->query->getDateFormat("'" . $this->dateFormatter->format($b, 'custom', DateTimeItemInterface::DATETIME_STORAGE_FORMAT, DateTimeItemInterface::STORAGE_TIMEZONE) . "'", $this->dateFormat, TRUE);
 
     // This is safe because we are manually scrubbing the values.
     $operator = strtoupper($this->operator);
@@ -116,7 +117,7 @@ protected function opSimple($field) {
     $value = intval(strtotime($this->value['value'], $origin));
 
     // Convert to ISO. UTC is used since dates are stored in UTC.
-    $value = $this->query->getDateFormat("'" . $this->dateFormatter->format($value, 'custom', DATETIME_DATETIME_STORAGE_FORMAT, DATETIME_STORAGE_TIMEZONE) . "'", $this->dateFormat, TRUE);
+    $value = $this->query->getDateFormat("'" . $this->dateFormatter->format($value, 'custom', DateTimeItemInterface::DATETIME_STORAGE_FORMAT, DateTimeItemInterface::STORAGE_TIMEZONE) . "'", $this->dateFormat, TRUE);
 
     // This is safe because we are manually scrubbing the value.
     $field = $this->query->getDateFormat($field, $this->dateFormat, TRUE);

core/modules/datetime/tests/src/Functional/DateTimeFieldTest.php

@@ -7,6 +7,7 @@
 use Drupal\Component\Utility\Unicode;
 use Drupal\Core\Datetime\DrupalDateTime;
 use Drupal\Core\Datetime\Entity\DateFormat;
+use Drupal\datetime\Plugin\Field\FieldType\DateTimeItemInterface;
 use Drupal\entity_test\Entity\EntityTest;
 use Drupal\field\Entity\FieldConfig;
 use Drupal\field\Entity\FieldStorageConfig;
@@ -58,7 +59,7 @@ public function testDateField() {
       // mimic the user in a different timezone simply entering '2012-12-31' via
       // the UI.
       $value = '2012-12-31 00:00:00';
-      $date = new DrupalDateTime($value, DATETIME_STORAGE_TIMEZONE);
+      $date = new DrupalDateTime($value, DateTimeItemInterface::STORAGE_TIMEZONE);
 
       // Submit a valid date and ensure it is accepted.
       $date_format = DateFormat::load('html_date')->getPattern();
@@ -114,8 +115,8 @@ public function testDateField() {
             case 'format_type':
               // Verify that a date is displayed. Since this is a date-only
               // field, it is expected to display the time as 00:00:00.
-              $expected = format_date($date->getTimestamp(), $new_value, '', DATETIME_STORAGE_TIMEZONE);
-              $expected_iso = format_date($date->getTimestamp(), 'custom', 'Y-m-d\TH:i:s\Z', DATETIME_STORAGE_TIMEZONE);
+              $expected = format_date($date->getTimestamp(), $new_value, '', DateTimeItemInterface::STORAGE_TIMEZONE);
+              $expected_iso = format_date($date->getTimestamp(), 'custom', 'Y-m-d\TH:i:s\Z', DateTimeItemInterface::STORAGE_TIMEZONE);
               $output = $this->renderTestEntity($id);
               $expected_markup = '<time datetime="' . $expected_iso . '" class="datetime">' . $expected . '</time>';
               $this->assertContains($expected_markup, $output, new FormattableMarkup('Formatted date field using %value format displayed as %expected with %expected_iso attribute in %timezone.', [
@@ -135,7 +136,7 @@ public function testDateField() {
       entity_get_display($this->field->getTargetEntityTypeId(), $this->field->getTargetBundle(), 'full')
         ->setComponent($field_name, $this->displayOptions)
         ->save();
-      $expected = $date->format(DATETIME_DATE_STORAGE_FORMAT);
+      $expected = $date->format(DateTimeItemInterface::DATE_STORAGE_FORMAT);
       $output = $this->renderTestEntity($id);
       $this->assertContains($expected, $output, new FormattableMarkup('Formatted date field using plain format displayed as %expected in %timezone.', [
         '%expected' => $expected,
@@ -296,7 +297,7 @@ public function testDatetimeField() {
     entity_get_display($this->field->getTargetEntityTypeId(), $this->field->getTargetBundle(), 'full')
       ->setComponent($field_name, $this->displayOptions)
       ->save();
-    $expected = $date->format(DATETIME_DATETIME_STORAGE_FORMAT);
+    $expected = $date->format(DateTimeItemInterface::DATETIME_STORAGE_FORMAT);
     $output = $this->renderTestEntity($id);
     $this->assertContains($expected, $output, SafeMarkup::format('Formatted date field using plain format displayed as %expected.', ['%expected' => $expected]));
 
@@ -329,7 +330,7 @@ public function testDatetimeField() {
     $entity = EntityTest::load($id);
     $field_name = $this->fieldStorage->getName();
     $date = DrupalDateTime::createFromTimestamp($timestamp, 'UTC');
-    $entity->{$field_name}->value = $date->format(DATETIME_DATETIME_STORAGE_FORMAT);
+    $entity->{$field_name}->value = $date->format(DateTimeItemInterface::DATETIME_STORAGE_FORMAT);
     $entity->save();
 
     $this->displayOptions['type'] = 'datetime_time_ago';
@@ -356,7 +357,7 @@ public function testDatetimeField() {
     $entity = EntityTest::load($id);
     $field_name = $this->fieldStorage->getName();
     $date = DrupalDateTime::createFromTimestamp($timestamp, 'UTC');
-    $entity->{$field_name}->value = $date->format(DATETIME_DATETIME_STORAGE_FORMAT);
+    $entity->{$field_name}->value = $date->format(DateTimeItemInterface::DATETIME_STORAGE_FORMAT);
     $entity->save();
 
     entity_get_display($this->field->getTargetEntityTypeId(), $this->field->getTargetBundle(), 'full')
@@ -695,7 +696,7 @@ public function testDefaultValue() {
       $new_node = Node::create(['type' => 'date_content']);
       $expected_date = new DrupalDateTime('now', drupal_get_user_timezone());
       $this->assertEqual($new_node->get($field_name)
-        ->offsetGet(0)->value, $expected_date->format(DATETIME_DATE_STORAGE_FORMAT));
+        ->offsetGet(0)->value, $expected_date->format(DateTimeItemInterface::DATE_STORAGE_FORMAT));
 
       // Set an invalid relative default_value to test validation.
       $field_edit = [
@@ -734,7 +735,7 @@ public function testDefaultValue() {
       $new_node = Node::create(['type' => 'date_content']);
       $expected_date = new DrupalDateTime('+90 days', drupal_get_user_timezone());
       $this->assertEqual($new_node->get($field_name)
-        ->offsetGet(0)->value, $expected_date->format(DATETIME_DATE_STORAGE_FORMAT));
+        ->offsetGet(0)->value, $expected_date->format(DateTimeItemInterface::DATE_STORAGE_FORMAT));
 
       // Remove default value.
       $field_edit = [

core/modules/datetime/tests/src/Kernel/DateTimeItemTest.php

@@ -5,6 +5,7 @@
 use Drupal\Core\Field\FieldItemListInterface;
 use Drupal\Core\Field\FieldItemInterface;
 use Drupal\datetime\Plugin\Field\FieldType\DateTimeItem;
+use Drupal\datetime\Plugin\Field\FieldType\DateTimeItemInterface;
 use Drupal\entity_test\Entity\EntityTest;
 use Drupal\field\Entity\FieldConfig;
 use Drupal\Tests\field\Kernel\FieldKernelTestBase;
@@ -80,19 +81,19 @@ public function testDateTime() {
     $this->assertTrue($entity->field_datetime[0] instanceof FieldItemInterface, 'Field item implements interface.');
     $this->assertEqual($entity->field_datetime->value, $value);
     $this->assertEqual($entity->field_datetime[0]->value, $value);
-    $this->assertEquals(DATETIME_STORAGE_TIMEZONE, $entity->field_datetime->date->getTimeZone()->getName());
+    $this->assertEquals(DateTimeItemInterface::STORAGE_TIMEZONE, $entity->field_datetime->date->getTimeZone()->getName());
 
     // Verify changing the date value.
     $new_value = '2016-11-04T00:21:00';
     $entity->field_datetime->value = $new_value;
     $this->assertEqual($entity->field_datetime->value, $new_value);
-    $this->assertEquals(DATETIME_STORAGE_TIMEZONE, $entity->field_datetime->date->getTimeZone()->getName());
+    $this->assertEquals(DateTimeItemInterface::STORAGE_TIMEZONE, $entity->field_datetime->date->getTimeZone()->getName());
 
     // Read changed entity and assert changed values.
     $this->entityValidateAndSave($entity);
     $entity = EntityTest::load($id);
     $this->assertEqual($entity->field_datetime->value, $new_value);
-    $this->assertEquals(DATETIME_STORAGE_TIMEZONE, $entity->field_datetime->date->getTimeZone()->getName());
+    $this->assertEquals(DateTimeItemInterface::STORAGE_TIMEZONE, $entity->field_datetime->date->getTimeZone()->getName());
 
     // Test the generateSampleValue() method.
     $entity = EntityTest::create();
@@ -121,7 +122,7 @@ public function testDateOnly() {
     $this->assertTrue($entity->field_datetime[0] instanceof FieldItemInterface, 'Field item implements interface.');
     $this->assertEqual($entity->field_datetime->value, $value);
     $this->assertEqual($entity->field_datetime[0]->value, $value);
-    $this->assertEquals(DATETIME_STORAGE_TIMEZONE, $entity->field_datetime->date->getTimeZone()->getName());
+    $this->assertEquals(DateTimeItemInterface::STORAGE_TIMEZONE, $entity->field_datetime->date->getTimeZone()->getName());
     $this->assertEquals('12:00:00', $entity->field_datetime->date->format('H:i:s'));
     $entity->field_datetime->date->setDefaultDateTime();
     $this->assertEquals('12:00:00', $entity->field_datetime->date->format('H:i:s'));
@@ -130,7 +131,7 @@ public function testDateOnly() {
     $new_value = '2016-11-04';
     $entity->field_datetime->value = $new_value;
     $this->assertEqual($entity->field_datetime->value, $new_value);
-    $this->assertEquals(DATETIME_STORAGE_TIMEZONE, $entity->field_datetime->date->getTimeZone()->getName());
+    $this->assertEquals(DateTimeItemInterface::STORAGE_TIMEZONE, $entity->field_datetime->date->getTimeZone()->getName());
     $this->assertEquals('12:00:00', $entity->field_datetime->date->format('H:i:s'));
     $entity->field_datetime->date->setDefaultDateTime();
     $this->assertEquals('12:00:00', $entity->field_datetime->date->format('H:i:s'));
@@ -139,7 +140,7 @@ public function testDateOnly() {
     $this->entityValidateAndSave($entity);
     $entity = EntityTest::load($id);
     $this->assertEqual($entity->field_datetime->value, $new_value);
-    $this->assertEquals(DATETIME_STORAGE_TIMEZONE, $entity->field_datetime->date->getTimeZone()->getName());
+    $this->assertEquals(DateTimeItemInterface::STORAGE_TIMEZONE, $entity->field_datetime->date->getTimeZone()->getName());
     $this->assertEquals('12:00:00', $entity->field_datetime->date->format('H:i:s'));
     $entity->field_datetime->date->setDefaultDateTime();
     $this->assertEquals('12:00:00', $entity->field_datetime->date->format('H:i:s'));
@@ -170,7 +171,7 @@ public function testSetValue() {
     $id = $entity->id();
     $entity = EntityTest::load($id);
     $this->assertEqual($entity->field_datetime[0]->value, $value, 'DateTimeItem::setValue() works with string value.');
-    $this->assertEquals(DATETIME_STORAGE_TIMEZONE, $entity->field_datetime->date->getTimeZone()->getName());
+    $this->assertEquals(DateTimeItemInterface::STORAGE_TIMEZONE, $entity->field_datetime->date->getTimeZone()->getName());
 
     // Test DateTimeItem::setValue() using property array.
     $entity = EntityTest::create();
@@ -181,7 +182,7 @@ public function testSetValue() {
     $id = $entity->id();
     $entity = EntityTest::load($id);
     $this->assertEqual($entity->field_datetime[0]->value, $value, 'DateTimeItem::setValue() works with array value.');
-    $this->assertEquals(DATETIME_STORAGE_TIMEZONE, $entity->field_datetime->date->getTimeZone()->getName());
+    $this->assertEquals(DateTimeItemInterface::STORAGE_TIMEZONE, $entity->field_datetime->date->getTimeZone()->getName());
 
     // Test a date-only field.
     $this->fieldStorage->setSetting('datetime_type', DateTimeItem::DATETIME_TYPE_DATE);
@@ -196,7 +197,7 @@ public function testSetValue() {
     $id = $entity->id();
     $entity = EntityTest::load($id);
     $this->assertEqual($entity->field_datetime[0]->value, $value, 'DateTimeItem::setValue() works with string value.');
-    $this->assertEquals(DATETIME_STORAGE_TIMEZONE, $entity->field_datetime->date->getTimeZone()->getName());
+    $this->assertEquals(DateTimeItemInterface::STORAGE_TIMEZONE, $entity->field_datetime->date->getTimeZone()->getName());
 
     // Test DateTimeItem::setValue() using property array.
     $entity = EntityTest::create();
@@ -207,7 +208,7 @@ public function testSetValue() {
     $id = $entity->id();
     $entity = EntityTest::load($id);
     $this->assertEqual($entity->field_datetime[0]->value, $value, 'DateTimeItem::setValue() works with array value.');
-    $this->assertEquals(DATETIME_STORAGE_TIMEZONE, $entity->field_datetime->date->getTimeZone()->getName());
+    $this->assertEquals(DateTimeItemInterface::STORAGE_TIMEZONE, $entity->field_datetime->date->getTimeZone()->getName());
   }
 
   /**
@@ -227,7 +228,7 @@ public function testSetValueProperty() {
     $id = $entity->id();
     $entity = EntityTest::load($id);
     $this->assertEqual($entity->field_datetime[0]->value, $value, '"Value" property can be set directly.');
-    $this->assertEquals(DATETIME_STORAGE_TIMEZONE, $entity->field_datetime->date->getTimeZone()->getName());
+    $this->assertEquals(DateTimeItemInterface::STORAGE_TIMEZONE, $entity->field_datetime->date->getTimeZone()->getName());
 
     // Test Date::setValue() with a date-only field.
     // Test a date+time field.
@@ -242,7 +243,7 @@ public function testSetValueProperty() {
     $id = $entity->id();
     $entity = EntityTest::load($id);
     $this->assertEqual($entity->field_datetime[0]->value, $value, '"Value" property can be set directly.');
-    $this->assertEquals(DATETIME_STORAGE_TIMEZONE, $entity->field_datetime->date->getTimeZone()->getName());
+    $this->assertEquals(DateTimeItemInterface::STORAGE_TIMEZONE, $entity->field_datetime->date->getTimeZone()->getName());
   }
 
   /**

core/modules/datetime/tests/src/Kernel/Views/FilterDateTest.php

@@ -3,6 +3,7 @@
 namespace Drupal\Tests\datetime\Kernel\Views;
 
 use Drupal\datetime\Plugin\Field\FieldType\DateTimeItem;
+use Drupal\datetime\Plugin\Field\FieldType\DateTimeItemInterface;
 use Drupal\field\Entity\FieldStorageConfig;
 use Drupal\node\Entity\Node;
 use Drupal\views\Views;
@@ -42,11 +43,11 @@ protected function setUp($import_test_views = TRUE) {
 
     $dates = [
       // Tomorrow.
-      \Drupal::service('date.formatter')->format(static::$date + 86400, 'custom', DATETIME_DATE_STORAGE_FORMAT, DATETIME_STORAGE_TIMEZONE),
+      \Drupal::service('date.formatter')->format(static::$date + 86400, 'custom', DateTimeItemInterface::DATE_STORAGE_FORMAT, DateTimeItemInterface::STORAGE_TIMEZONE),
       // Today.
-      \Drupal::service('date.formatter')->format(static::$date, 'custom', DATETIME_DATE_STORAGE_FORMAT, DATETIME_STORAGE_TIMEZONE),
+      \Drupal::service('date.formatter')->format(static::$date, 'custom', DateTimeItemInterface::DATE_STORAGE_FORMAT, DateTimeItemInterface::STORAGE_TIMEZONE),
       // Yesterday.
-      \Drupal::service('date.formatter')->format(static::$date - 86400, 'custom', DATETIME_DATE_STORAGE_FORMAT, DATETIME_STORAGE_TIMEZONE),
+      \Drupal::service('date.formatter')->format(static::$date - 86400, 'custom', DateTimeItemInterface::DATE_STORAGE_FORMAT, DateTimeItemInterface::STORAGE_TIMEZONE),
     ];
 
     foreach ($dates as $date) {

core/modules/datetime/tests/src/Kernel/Views/FilterDateTimeTest.php

@@ -2,6 +2,7 @@
 
 namespace Drupal\Tests\datetime\Kernel\Views;
 
+use Drupal\datetime\Plugin\Field\FieldType\DateTimeItemInterface;
 use Drupal\node\Entity\Node;
 use Drupal\views\Views;
 
@@ -45,7 +46,7 @@ protected function setUp($import_test_views = TRUE) {
       '2002-10-10T14:14:14',
       // The date storage timezone is used (this mimics the steps taken in the
       // widget: \Drupal\datetime\Plugin\Field\FieldWidget::messageFormValues().
-      \Drupal::service('date.formatter')->format(static::$date, 'custom', DATETIME_DATETIME_STORAGE_FORMAT, DATETIME_STORAGE_TIMEZONE),
+      \Drupal::service('date.formatter')->format(static::$date, 'custom', DateTimeItemInterface::DATETIME_STORAGE_FORMAT, DateTimeItemInterface::STORAGE_TIMEZONE),
     ];
     foreach ($dates as $date) {
       $node = Node::create([
@@ -181,7 +182,7 @@ protected function _testExact() {
     $view->filter[$field]->value['max'] = '';
     // Use the date from node 3. Use the site timezone (mimics a value entered
     // through the UI).
-    $view->filter[$field]->value['value'] = \Drupal::service('date.formatter')->format(static::$date, 'custom', DATETIME_DATETIME_STORAGE_FORMAT, static::$timezone);
+    $view->filter[$field]->value['value'] = \Drupal::service('date.formatter')->format(static::$date, 'custom', DateTimeItemInterface::DATETIME_STORAGE_FORMAT, static::$timezone);
     $view->setDisplay('default');
     $this->executeView($view);
     $expected_result = [

core/modules/datetime_range/src/Plugin/Field/FieldType/DateRangeFieldItemList.php

@@ -8,6 +8,7 @@
 use Drupal\Core\Field\FieldItemList;
 use Drupal\Core\Form\FormStateInterface;
 use Drupal\datetime\Plugin\Field\FieldType\DateTimeFieldItemList;
+use Drupal\datetime\Plugin\Field\FieldType\DateTimeItemInterface;
 
 /**
  * Represents a configurable entity daterange field.
@@ -105,18 +106,18 @@ public static function processDefaultValue($default_value, FieldableEntityInterf
       // only provide a default value for the first item, as do all fields.
       // Otherwise, there is no way to clear out unwanted values on multiple
       // value fields.
-      $storage_format = $definition->getSetting('datetime_type') == DateRangeItem::DATETIME_TYPE_DATE ? DATETIME_DATE_STORAGE_FORMAT : DATETIME_DATETIME_STORAGE_FORMAT;
+      $storage_format = $definition->getSetting('datetime_type') == DateRangeItem::DATETIME_TYPE_DATE ? DateTimeItemInterface::DATE_STORAGE_FORMAT : DateTimeItemInterface::DATETIME_STORAGE_FORMAT;
       $default_values = [[]];
 
       if (!empty($default_value[0]['default_date_type'])) {
-        $start_date = new DrupalDateTime($default_value[0]['default_date'], DATETIME_STORAGE_TIMEZONE);
+        $start_date = new DrupalDateTime($default_value[0]['default_date'], DateTimeItemInterface::STORAGE_TIMEZONE);
         $start_value = $start_date->format($storage_format);
         $default_values[0]['value'] = $start_value;
         $default_values[0]['start_date'] = $start_date;
       }
 
       if (!empty($default_value[0]['default_end_date_type'])) {
-        $end_date = new DrupalDateTime($default_value[0]['default_end_date'], DATETIME_STORAGE_TIMEZONE);
+        $end_date = new DrupalDateTime($default_value[0]['default_end_date'], DateTimeItemInterface::STORAGE_TIMEZONE);
         $end_value = $end_date->format($storage_format);
         $default_values[0]['end_value'] = $end_value;
         $default_values[0]['end_date'] = $end_date;

core/modules/datetime_range/src/Plugin/Field/FieldType/DateRangeItem.php

@@ -8,6 +8,7 @@
 use Drupal\Core\TypedData\DataDefinition;
 use Drupal\datetime\DateTimeComputed;
 use Drupal\datetime\Plugin\Field\FieldType\DateTimeItem;
+use Drupal\datetime\Plugin\Field\FieldType\DateTimeItemInterface;
 
 /**
  * Plugin implementation of the 'daterange' field type.
@@ -96,12 +97,12 @@ public static function generateSampleValue(FieldDefinitionInterface $field_defin
     $start = REQUEST_TIME - mt_rand(0, 86400 * 365) - 86400;
     $end = $start + 86400;
     if ($type == static::DATETIME_TYPE_DATETIME) {
-      $values['value'] = gmdate(DATETIME_DATETIME_STORAGE_FORMAT, $start);
-      $values['end_value'] = gmdate(DATETIME_DATETIME_STORAGE_FORMAT, $end);
+      $values['value'] = gmdate(DateTimeItemInterface::DATETIME_STORAGE_FORMAT, $start);
+      $values['end_value'] = gmdate(DateTimeItemInterface::DATETIME_STORAGE_FORMAT, $end);
     }
     else {
-      $values['value'] = gmdate(DATETIME_DATE_STORAGE_FORMAT, $start);
-      $values['end_value'] = gmdate(DATETIME_DATE_STORAGE_FORMAT, $end);
+      $values['value'] = gmdate(DateTimeItemInterface::DATE_STORAGE_FORMAT, $start);
+      $values['end_value'] = gmdate(DateTimeItemInterface::DATE_STORAGE_FORMAT, $end);
     }
     return $values;
   }

core/modules/datetime_range/src/Plugin/Field/FieldWidget/DateRangeWidgetBase.php

@@ -5,6 +5,7 @@
 use Drupal\Core\Datetime\DrupalDateTime;
 use Drupal\Core\Field\FieldItemListInterface;
 use Drupal\Core\Form\FormStateInterface;
+use Drupal\datetime\Plugin\Field\FieldType\DateTimeItemInterface;
 use Drupal\datetime\Plugin\Field\FieldWidget\DateTimeWidgetBase;
 use Drupal\datetime_range\Plugin\Field\FieldType\DateRangeItem;
 
@@ -57,7 +58,7 @@ public function massageFormValues(array $values, array $form, FormStateInterface
         $start_date = $item['value'];
         switch ($this->getFieldSetting('datetime_type')) {
           case DateRangeItem::DATETIME_TYPE_DATE:
-            $format = DATETIME_DATE_STORAGE_FORMAT;
+            $format = DateTimeItemInterface::DATE_STORAGE_FORMAT;
             break;
 
           case DateRangeItem::DATETIME_TYPE_ALLDAY:
@@ -67,15 +68,15 @@ public function massageFormValues(array $values, array $form, FormStateInterface
             // we need to explicitly set the timezone.
             $start_date->setTimeZone(timezone_open(drupal_get_user_timezone()));
             $start_date->setTime(0, 0, 0);
-            $format = DATETIME_DATETIME_STORAGE_FORMAT;
+            $format = DateTimeItemInterface::DATETIME_STORAGE_FORMAT;
             break;
 
           default:
-            $format = DATETIME_DATETIME_STORAGE_FORMAT;
+            $format = DateTimeItemInterface::DATETIME_STORAGE_FORMAT;
             break;
         }
         // Adjust the date for storage.
-        $start_date->setTimezone(new \DateTimezone(DATETIME_STORAGE_TIMEZONE));
+        $start_date->setTimezone(new \DateTimezone(DateTimeItemInterface::STORAGE_TIMEZONE));
         $item['value'] = $start_date->format($format);
       }
 
@@ -84,7 +85,7 @@ public function massageFormValues(array $values, array $form, FormStateInterface
         $end_date = $item['end_value'];
         switch ($this->getFieldSetting('datetime_type')) {
           case DateRangeItem::DATETIME_TYPE_DATE:
-            $format = DATETIME_DATE_STORAGE_FORMAT;
+            $format = DateTimeItemInterface::DATE_STORAGE_FORMAT;
             break;
 
           case DateRangeItem::DATETIME_TYPE_ALLDAY:
@@ -94,15 +95,15 @@ public function massageFormValues(array $values, array $form, FormStateInterface
             // we need to explicitly set the timezone.
             $end_date->setTimeZone(timezone_open(drupal_get_user_timezone()));
             $end_date->setTime(23, 59, 59);
-            $format = DATETIME_DATETIME_STORAGE_FORMAT;
+            $format = DateTimeItemInterface::DATETIME_STORAGE_FORMAT;
             break;
 
           default:
-            $format = DATETIME_DATETIME_STORAGE_FORMAT;
+            $format = DateTimeItemInterface::DATETIME_STORAGE_FORMAT;
             break;
         }
         // Adjust the date for storage.
-        $end_date->setTimezone(new \DateTimezone(DATETIME_STORAGE_TIMEZONE));
+        $end_date->setTimezone(new \DateTimezone(DateTimeItemInterface::STORAGE_TIMEZONE));
         $item['end_value'] = $end_date->format($format);
       }
     }

core/modules/migrate/src/Plugin/migrate/process/FormatDate.php

@@ -21,7 +21,8 @@
  *
  * Examples:
  *
- * Example usage for date only fields (DATETIME_DATE_STORAGE_FORMAT):
+ * Example usage for date only fields
+ * (DateTimeItemInterface::DATE_STORAGE_FORMAT):
  * @code
  * process:
  *   field_date:
@@ -34,7 +35,8 @@
  * If the source value was '01/05/1955' the transformed value would be
  * 1955-01-05.
  *
- * Example usage for datetime fields (DATETIME_DATETIME_STORAGE_FORMAT):
+ * Example usage for datetime fields
+ * (DateTimeItemInterface::DATETIME_STORAGE_FORMAT):
  * @code
  * process:
  *   field_time:
@@ -65,6 +67,7 @@
  *
  * @see \DateTime::createFromFormat()
  * @see \Drupal\Component\Datetime\DateTimePlus::__construct()
+ * @see \Drupal\datetime\Plugin\Field\FieldType\DateTimeItemInterface
  * @see \Drupal\migrate\Plugin\MigrateProcessInterface
  *
  * @MigrateProcessPlugin(