Issue #2825860: Fix Notice: Undefined index: value in Drupal\views\Plugin\views\filter\NumericFilter->acceptExposedInput()

This MR combines:

• Tests introduced in https://www.drupal.org/project/drupal/issues/2825860#comment-14911701
• Solution proposed in https://www.drupal.org/project/drupal/issues/2825860#comment-14927726

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

@@ -125,11 +125,12 @@ protected function setUp($import_test_views = TRUE, $modules = ['views_test_conf
    */
   public function testExposedGroupedFilters() {
     // Expose the empty and not empty operators in a grouped filter.
-    $this->drupalGet('admin/structure/views/nojs/handler/test_filter_datetime/default/filter/' . $this->fieldName . '_value');
+    $filter_identifier = $this->fieldName . '_value';
+    $this->drupalGet('admin/structure/views/nojs/handler/test_filter_datetime/default/filter/' . $filter_identifier);
     $this->submitForm([], 'Expose filter');
     $this->submitForm([], 'Grouped filters');
 
-    // Test operators with different amount of expected values.
+    // Create groups with different amount of expected values.
     $edit = [];
     // No values are required.
     $edit['options[group_info][group_items][1][title]'] = 'empty';
@@ -162,24 +163,37 @@ public function testExposedGroupedFilters() {
     $this->drupalGet($path);
 
     // Filter the Preview by 'empty'.
-    $this->getSession()->getPage()->findField($this->fieldName . '_value')->selectOption('1');
+    $this->getSession()->getPage()->findField($filter_identifier)->selectOption('1');
     $this->getSession()->getPage()->pressButton('Apply');
     $this->assertIds([4]);
 
     // Filter the Preview by 'not empty'.
-    $this->getSession()->getPage()->findField($this->fieldName . '_value')->selectOption('2');
+    $this->getSession()->getPage()->findField($filter_identifier)->selectOption('2');
     $this->getSession()->getPage()->pressButton('Apply');
     $this->assertIds([1, 2, 3]);
 
     // Filter the Preview by 'less than'.
-    $this->getSession()->getPage()->findField($this->fieldName . '_value')->selectOption('3');
+    $this->getSession()->getPage()->findField($filter_identifier)->selectOption('3');
     $this->getSession()->getPage()->pressButton('Apply');
     $this->assertIds([2, 3]);
 
     // Filter the Preview by 'between'.
-    $this->getSession()->getPage()->findField($this->fieldName . '_value')->selectOption('4');
+    $this->getSession()->getPage()->findField($filter_identifier)->selectOption('4');
     $this->getSession()->getPage()->pressButton('Apply');
     $this->assertIds([2]);
+
+    // Change the identifier for grouped exposed filter.
+    $this->drupalGet('admin/structure/views/nojs/handler/test_filter_datetime/default/filter/' . $filter_identifier);
+    $filter_identifier = 'date';
+    $edit['options[group_info][identifier]'] = $filter_identifier;
+    $this->submitForm($edit, 'Apply');
+    $this->submitForm([], 'Save');
+
+    // Filter results again using a new filter identifier.
+    $this->drupalGet($path);
+    $this->getSession()->getPage()->findField($filter_identifier)->selectOption(2);
+    $this->getSession()->getPage()->pressButton('Apply');
+    $this->assertIds([1, 2, 3]);
   }
 
   /**
@@ -205,7 +219,8 @@ protected function assertIds(array $expected_ids = []): void {
    */
   public function testExposedFilterWithPager() {
     // Expose the empty and not empty operators in a grouped filter.
-    $this->drupalGet('admin/structure/views/nojs/handler/test_filter_datetime/default/filter/' . $this->fieldName . '_value');
+    $filter_identifier = $this->fieldName . '_value';
+    $this->drupalGet('admin/structure/views/nojs/handler/test_filter_datetime/default/filter/' . $filter_identifier);
     $this->submitForm([], t('Expose filter'));
 
     $edit = [];
@@ -232,7 +247,7 @@ public function testExposedFilterWithPager() {
     // Assert the page with filter in the future, one results without pager.
     $page = $this->getSession()->getPage();
     $now = \Drupal::time()->getRequestTime();
-    $page->fillField($this->fieldName . '_value', DrupalDateTime::createFromTimestamp($now + 1)->format('Y-m-d H:i:s'));
+    $page->fillField($filter_identifier, DrupalDateTime::createFromTimestamp($now + 1)->format('Y-m-d H:i:s'));
     $page->pressButton('Apply');
 
     $results = $this->cssSelect('.views-row');
@@ -240,7 +255,7 @@ public function testExposedFilterWithPager() {
     $this->assertSession()->pageTextNotContains('Next');
 
     // Assert the page with filter in the past, 3 results with pager.
-    $page->fillField($this->fieldName . '_value', DrupalDateTime::createFromTimestamp($now - 1000000)->format('Y-m-d H:i:s'));
+    $page->fillField($filter_identifier, DrupalDateTime::createFromTimestamp($now - 1000000)->format('Y-m-d H:i:s'));
     $this->getSession()->getPage()->pressButton('Apply');
     $results = $this->cssSelect('.views-row');
     $this->assertCount(2, $results);