Issue #2508866 by paulocs, slashrsm, raman.b, vakulrai, justanothermark,...

Issue #2508866 by paulocs, slashrsm, raman.b, vakulrai, justanothermark, kishor_kolekar, KapilV, ranjith_kumar_k_u, Rinku Jacob 13, AndrewTur, quietone, pameeela, alexpott, catch: Field description is not displayed with Timestamp datetime widget

core/lib/Drupal/Core/Datetime/Plugin/Field/FieldWidget/TimestampDatetimeWidget.php

@@ -35,7 +35,11 @@ public function formElement(FieldItemListInterface $items, $delta, array $elemen
       '#default_value' => $default_value,
       '#date_year_range' => '1902:2037',
     ];
-    $element['value']['#description'] = $this->t('Format: %format. Leave blank to use the time of form submission.', ['%format' => Datetime::formatExample($date_format . ' ' . $time_format)]);
+
+    $element['value']['#description'] = $element['#description'] !== ''
+    ? $element['#description']
+    : $this->t('Format: %format. Leave blank to use the time of form submission.',
+    ['%format' => Datetime::formatExample($date_format . ' ' . $time_format)]);
 
     return $element;
   }

core/tests/Drupal/FunctionalTests/Datetime/TimestampTest.php

@@ -79,6 +79,7 @@ protected function setUp(): void {
       'field_storage' => $this->fieldStorage,
       'bundle' => 'entity_test',
       'required' => TRUE,
+      'description' => 'Description for timestamp field.',
     ]);
     $this->field->save();
 
@@ -114,6 +115,9 @@ public function testWidget() {
     // Display creation form.
     $this->drupalGet('entity_test/add');
 
+    // Make sure the field description is properly displayed.
+    $this->assertSession()->pageTextContains('Description for timestamp field.');
+
     // Make sure the "datetime_timestamp" widget is on the page.
     $this->assertSession()->elementsCount('xpath', '//div[contains(@class, "field--widget-datetime-timestamp") and @id="edit-field-timestamp-wrapper"]', 1);