Issue #1668332 by rbayliss, Devin Carlson, sun: Added E-mail field type to core.

core/modules/field/modules/email/email.info

+name = E-mail
+description = Defines a field type for e-mail addresses.
+package = Core
+version = VERSION
+core = 8.x
+dependencies[] = field
+dependencies[] = text

core/modules/field/modules/email/email.install

+<?php
+
+/**
+ * @file
+ * Install, update and uninstall functions for the E-mail module.
+ */
+
+/**
+ * Implements hook_field_schema().
+ */
+function email_field_schema($field) {
+  $columns = array(
+    'value' => array(
+      'type' => 'varchar',
+      // The maximum length of an e-mail address is 254 characters. RFC 3696
+      // specifies a total length of 320 characters, but mentions that
+      // addresses longer than 256 characters are not normally useful. Erratum
+      // 1690 was then released which corrected this value to 254 characters.
+      // @see http://tools.ietf.org/html/rfc3696#section-3
+      // @see http://www.rfc-editor.org/errata_search.php?rfc=3696&eid=1690
+      'length' => 254,
+      'not null' => FALSE,
+    ),
+  );
+  return array(
+    'columns' => $columns,
+  );
+}

core/modules/field/modules/email/email.module

+<?php
+
+/**
+ * @file
+ * Defines a simple e-mail field type.
+ */
+
+/**
+ * Implements hook_help().
+ */
+function email_help($path, $arg) {
+  switch ($path) {
+    case 'admin/help#email':
+      $output = '';
+      $output .= '<h3>' . t('About') . '</h3>';
+      $output .= '<p>' . t('The E-mail module defines a field for storing e-mail addresses, for use with the Field module. E-mail addresses are validated to ensure they match the expected format. See the <a href="@field-help">Field module help page</a> for more information about fields.', array('@field-help' => url('admin/help/field'))) . '</p>';
+      return $output;
+  }
+}
+
+/**
+ * Implements hook_field_info().
+ */
+function email_field_info() {
+  return array(
+    'email' => array(
+      'label' => t('E-mail'),
+      'description' => t('This field stores an e-mail address in the database.'),
+      'default_widget' => 'email_default',
+      'default_formatter' => 'text_plain',
+    ),
+  );
+}
+
+/**
+ * Implements hook_field_is_empty().
+ */
+function email_field_is_empty($item, $field) {
+  return !isset($item['value']) || $item['value'] === '';
+}
+
+/**
+ * Implements hook_field_widget_info().
+ */
+function email_field_widget_info() {
+  return array(
+    'email_default' => array(
+      'label' => t('E-mail'),
+      'field types' => array('email'),
+    ),
+  );
+}
+
+/**
+ * Implements hook_field_widget_form().
+ */
+function email_field_widget_form(&$form, &$form_state, $field, $instance, $langcode, $items, $delta, $element) {
+  $element['value'] = $element + array(
+    '#type' => 'email',
+    '#default_value' => isset($items[$delta]['value']) ? $items[$delta]['value'] : NULL,
+  );
+  return $element;
+
+}
+
+/**
+ * Implements hook_field_formatter_info().
+ */
+function email_field_formatter_info() {
+  return array(
+    'email_mailto' => array(
+      'label' => t('Mailto link'),
+      'field types' => array('email'),
+    ),
+  );
+}
+
+/**
+ * Implements hook_field_formatter_info_alter().
+ */
+function email_field_formatter_info_alter(&$info) {
+  $info['text_plain']['field types'][] = 'email';
+}
+
+/**
+ * Implements hook_field_formatter_view().
+ */
+function email_field_formatter_view($entity_type, $entity, $field, $instance, $langcode, $items, $display) {
+  $element = array();
+  foreach ($items as $delta => $item) {
+    $element[$delta] = array(
+      '#type' => 'link',
+      '#title' => $item['value'],
+      '#href' => 'mailto:' . $item['value'],
+    );
+  }
+  return $element;
+}

core/modules/field/modules/email/lib/Drupal/email/Tests/EmailFieldTest.php

+<?php
+
+/**
+ * @file
+ * Definition of Drupal\email\Tests\EmailFieldTest.
+ */
+
+namespace Drupal\email\Tests;
+
+use Drupal\simpletest\WebTestBase;
+
+/**
+ * Tests e-mail field functionality.
+ */
+class EmailFieldTest extends WebTestBase {
+
+  /**
+   * Modules to enable.
+   *
+   * @var array
+   */
+  public static $modules = array('node', 'field_test', 'email', 'field_ui');
+
+  public static function getInfo() {
+    return array(
+      'name'  => 'E-mail field',
+      'description'  => 'Tests e-mail field functionality.',
+      'group' => 'Field types',
+    );
+  }
+
+  function setUp() {
+    parent::setUp();
+
+    $this->web_user = $this->drupalCreateUser(array(
+      'access field_test content',
+      'administer field_test content',
+      'administer content types',
+    ));
+    $this->drupalLogin($this->web_user);
+  }
+
+  /**
+   * Tests e-mail field.
+   */
+  function testEmailField() {
+    // Create a field with settings to validate.
+    $this->field = array(
+      'field_name' => drupal_strtolower($this->randomName()),
+      'type' => 'email',
+    );
+    field_create_field($this->field);
+    $this->instance = array(
+      'field_name' => $this->field['field_name'],
+      'entity_type' => 'test_entity',
+      'bundle' => 'test_bundle',
+      'widget' => array(
+        'type' => 'email_default',
+      ),
+      'display' => array(
+        'full' => array(
+          'type' => 'email_mailto',
+        ),
+      ),
+    );
+    field_create_instance($this->instance);
+
+    // Display creation form.
+    $this->drupalGet('test-entity/add/test_bundle');
+    $langcode = LANGUAGE_NOT_SPECIFIED;
+    $this->assertFieldByName("{$this->field['field_name']}[$langcode][0][value]", '', 'Widget found.');
+
+    // Submit a valid e-mail address and ensure it is accepted.
+    $value = 'test@example.com';
+    $edit = array(
+      "{$this->field['field_name']}[$langcode][0][value]" => $value,
+    );
+    $this->drupalPost(NULL, $edit, t('Save'));
+    preg_match('|test-entity/manage/(\d+)/edit|', $this->url, $match);
+    $id = $match[1];
+    $this->assertRaw(t('test_entity @id has been created.', array('@id' => $id)));
+    $this->assertRaw($value);
+
+    // Verify that a mailto link is displayed.
+    $entity = field_test_entity_test_load($id);
+    $entity->content = field_attach_view('test_entity', $entity, 'full');
+    $this->drupalSetContent(drupal_render($entity->content));
+    $this->assertLinkByHref('mailto:test@example.com');
+  }
+}