Issue #3500045 by nikathone: Text filter is hiding everything when no value is passed

config/schema/views_csv_source.views.schema.yml

@@ -18,6 +18,19 @@ views.filter.views_csv_source_filter:
     key:
       type: string
       label: 'Column name key'
+    expose:
+      type: mapping
+      label: 'Exposed'
+      mapping:
+        required:
+          type: boolean
+          label: 'Required'
+        placeholder:
+          type: label
+          label: 'Placeholder'
+    value:
+      type: string
+      label: 'Value'
 
 views.filter.views_csv_source_filter_select:
   type: views_filter

src/Plugin/views/filter/ViewsCsvFilter.php

@@ -18,6 +18,47 @@ class ViewsCsvFilter extends FilterPluginBase {
   use ColumnSelectorTrait;
   use ViewsCsvFilterTrait;
 
+  /**
+   * Exposed filter options.
+   *
+   * @var bool
+   */
+  protected $alwaysMultiple = TRUE;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function defineOptions() {
+    $options = parent::defineOptions();
+
+    $options['expose']['contains']['required'] = ['default' => FALSE];
+    $options['expose']['contains']['placeholder'] = ['default' => ''];
+
+    return $options;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function defaultExposeOptions() {
+    parent::defaultExposeOptions();
+    $this->options['expose']['placeholder'] = NULL;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function buildExposeForm(&$form, FormStateInterface $form_state) {
+    parent::buildExposeForm($form, $form_state);
+    $form['expose']['placeholder'] = [
+      '#type' => 'textfield',
+      '#default_value' => $this->options['expose']['placeholder'],
+      '#title' => $this->t('Placeholder'),
+      '#size' => 40,
+      '#description' => $this->t('Hint text that appears inside the field when empty.'),
+    ];
+  }
+
   /**
    * Operators.
    *

tests/modules/views_csv_source_test/test_views/views.view.test_views_csv_source.yml

@@ -70,6 +70,34 @@ display:
           request_body: ''
           show_errors: true
           header_index: 0
+      filters:
+        value:
+          id: value
+          table: csv
+          field: value
+          relationship: none
+          group_type: group
+          admin_label: ''
+          plugin_id: views_csv_source_filter
+          operator: '='
+          value: ''
+          group: 1
+          exposed: true
+          expose:
+            operator_id: value_op
+            label: 'Filter by Geography name'
+            description: ''
+            use_operator: false
+            operator: value_op
+            operator_limit_selection: false
+            operator_list: {}
+            identifier: geography_name
+            required: false
+            remember: false
+            multiple: false
+            remember_roles:
+              authenticated: authenticated
+          key: 'Geography name'
   page_1:
     id: page_1
     display_title: 'Page display'

tests/src/Unit/Query/SelectTest.php

@@ -526,10 +526,10 @@ class SelectTest extends UnitTestCase {
     $count = 7;
     $header_index_overrides = [
       'header_index' => 1,
-      'csv_file' => $this->retrieveResource('/views_csv_data_with_header_index_moved_test.csv')
+      'csv_file' => $this->retrieveResource('/views_csv_data_with_header_index_moved_test.csv'),
     ];
     return [
-      'no_overrides' => [[],  $count, 4, []],
+      'no_overrides' => [[], $count, 4, []],
       'header_index_overrides' => [
         $header_index_overrides,
         $count,