Issue #1982776 by netsensei, Dave Reid, plopesc: Formatters do not support weights like widgets do.

core/lib/Drupal/Core/Field/Annotation/FieldFormatter.php

@@ -74,4 +74,13 @@ class FieldFormatter extends Plugin {
    */
   public $settings = array();
 
+  /**
+   * An integer to determine the weight of this formatter relative to other
+   * formatter in the Field UI when selecting a formatter for a given field
+   * instance.
+   *
+   * @var int optional
+   */
+  public $weight = NULL;
+
 }

core/lib/Drupal/Core/Field/FormatterPluginManager.php

@@ -167,13 +167,15 @@ public function prepareConfiguration($field_type, array $configuration) {
    */
   public function getOptions($field_type = NULL) {
     if (!isset($this->formatterOptions)) {
-      $field_types = $this->fieldTypeManager->getDefinitions();
       $options = array();
-      foreach ($this->getDefinitions() as $name => $formatter) {
-        foreach ($formatter['field_types'] as $formatter_field_type) {
+      $field_types = $this->fieldTypeManager->getDefinitions();
+      $formatter_types = $this->getDefinitions();
+      uasort($formatter_types, array('Drupal\Component\Utility\SortArray', 'sortByWeightElement'));
+      foreach ($formatter_types as $name => $formatter_type) {
+        foreach ($formatter_type['field_types'] as $formatter_field_type) {
           // Check that the field type exists.
           if (isset($field_types[$formatter_field_type])) {
-            $options[$formatter_field_type][$name] = $formatter['label'];
+            $options[$formatter_field_type][$name] = $formatter_type['label'];
           }
         }
       }

core/modules/field/tests/modules/field_test/lib/Drupal/field_test/Plugin/Field/FieldFormatter/TestFieldDefaultFormatter.php

@@ -22,7 +22,8 @@
  *   },
  *   settings = {
  *     "test_formatter_setting" = "dummy test string"
- *   }
+ *   },
+ *   weight = 1
  * )
  */
 class TestFieldDefaultFormatter extends FormatterBase {

core/modules/field/tests/modules/field_test/lib/Drupal/field_test/Plugin/Field/FieldFormatter/TestFieldEmptyFormatter.php

@@ -21,7 +21,8 @@
  *   },
  *   settings = {
  *     "test_empty_string" = "**EMPTY FIELD**"
- *   }
+ *   },
+ *   weight = -5
  * )
  */
 class TestFieldEmptyFormatter extends FormatterBase {

core/modules/field/tests/modules/field_test/lib/Drupal/field_test/Plugin/Field/FieldFormatter/TestFieldEmptySettingFormatter.php

@@ -21,7 +21,8 @@
  *   },
  *   settings = {
  *     "field_empty_setting" = ""
- *   }
+ *   },
+ *   weight = -1
  * )
  */
 class TestFieldEmptySettingFormatter extends FormatterBase {

core/modules/field/tests/modules/field_test/lib/Drupal/field_test/Plugin/Field/FieldFormatter/TestFieldMultipleFormatter.php

@@ -22,7 +22,8 @@
  *   },
  *   settings = {
  *     "test_formatter_setting_multiple" = "dummy test string"
- *   }
+ *   },
+ *   weight = 5
  * )
  */
 class TestFieldMultipleFormatter extends FormatterBase {

core/modules/field/tests/modules/field_test/lib/Drupal/field_test/Plugin/Field/FieldFormatter/TestFieldNoSettingsFormatter.php

@@ -19,6 +19,7 @@
  *   field_types = {
  *     "test_field",
  *   },
+ *   weight = -10
  * )
  */
 class TestFieldNoSettingsFormatter extends FormatterBase {

core/modules/field/tests/modules/field_test/lib/Drupal/field_test/Plugin/Field/FieldFormatter/TestFieldPrepareViewFormatter.php

@@ -22,7 +22,8 @@
  *   },
  *   settings = {
  *     "test_formatter_setting_additional" = "dummy test string"
- *   }
+ *   },
+ *   weight = 10
  * )
  */
 class TestFieldPrepareViewFormatter extends FormatterBase {

core/modules/field/tests/modules/field_test/lib/Drupal/field_test/Plugin/Field/FieldWidget/TestFieldWidget.php

@@ -23,7 +23,8 @@
  *   },
  *   settings = {
  *     "test_widget_setting" = "dummy test string"
- *   }
+ *   },
+ *   weight = -10
  * )
  */
 class TestFieldWidget extends WidgetBase {

core/modules/field/tests/modules/field_test/lib/Drupal/field_test/Plugin/Field/FieldWidget/TestFieldWidgetMultiple.php

@@ -25,7 +25,8 @@
  *   settings = {
  *     "test_widget_setting_multiple" = "dummy test string"
  *   },
- *   multiple_values = TRUE
+ *   multiple_values = TRUE,
+ *   weight = 10
  * )
  */
 class TestFieldWidgetMultiple extends WidgetBase {

core/modules/field_ui/lib/Drupal/field_ui/Tests/ManageDisplayTest.php

@@ -51,12 +51,28 @@ function testFormatterUI() {
     $setting_name = key($default_settings);
     $setting_value = $display_options['settings'][$setting_name];
 
-    // Display the "Manage display" screen and check that the expected formatter is
-    // selected.
+    // Display the "Manage display" screen and check that the expected formatter
+    // is selected.
     $this->drupalGet($manage_display);
     $this->assertFieldByName('fields[field_test][type]', $format, 'The expected formatter is selected.');
     $this->assertText("$setting_name: $setting_value", 'The expected summary is displayed.');
 
+    // Check whether formatter weights are respected.
+    $result = $this->xpath('//select[@id=:id]/option', array(':id' => 'edit-fields-field-test-type'));
+    $options = array_map(function($item) {
+      return (string) $item->attributes()->value[0];
+    }, $result);
+    $expected_options = array (
+      'field_no_settings',
+      'field_empty_test',
+      'field_empty_setting',
+      'field_test_default',
+      'field_test_multiple',
+      'field_test_with_prepare_view',
+      'hidden',
+    );
+    $this->assertEqual($options, $expected_options, 'The expected formatter ordering is respected.');
+
     // Change the formatter and check that the summary is updated.
     $edit = array('fields[field_test][type]' => 'field_test_multiple', 'refresh_rows' => 'field_test');
     $this->drupalPostAjaxForm(NULL, $edit, array('op' => t('Refresh')));
@@ -139,6 +155,18 @@ public function testWidgetUI() {
     $this->assertFieldByName('fields[field_test][type]', $widget_type, 'The expected widget is selected.');
     $this->assertText("$setting_name: $setting_value", 'The expected summary is displayed.');
 
+    // Check whether widget weights are respected.
+    $result = $this->xpath('//select[@id=:id]/option', array(':id' => 'edit-fields-field-test-type'));
+    $options = array_map(function($item) {
+      return (string) $item->attributes()->value[0];
+    }, $result);
+    $expected_options = array (
+      'test_field_widget',
+      'test_field_widget_multiple',
+      'hidden',
+    );
+    $this->assertEqual($options, $expected_options, 'The expected widget ordering is respected.');
+
     // Change the widget and check that the summary is updated.
     $edit = array('fields[field_test][type]' => 'test_field_widget_multiple', 'refresh_rows' => 'field_test');
     $this->drupalPostAjaxForm(NULL, $edit, array('op' => t('Refresh')));