diff -u b/diff.views.inc b/diff.views.inc
--- b/diff.views.inc
+++ b/diff.views.inc
@@ -1,4 +1,5 @@
 <?php
+
 use Drupal\Core\Entity\EntityTypeInterface;
 
 /**
@@ -6,30 +7,28 @@
  */
 function diff_views_data() {
   $data = [];
-  $entity_types = \Drupal::entityTypeManager()->getDefinitions();
-  $revisionable_entity_types = array_filter($entity_types, function (EntityTypeInterface $entity_type) {
-    return $entity_type->isRevisionable();
-  });
 
   /** @var \Drupal\Core\Entity\EntityTypeInterface $entity_type */
-  foreach ($revisionable_entity_types as $entity_type) {
-    $revision_base_table = $entity_type->getRevisionDataTable() ?: $entity_type->getRevisionTable();
-
-    $data[$revision_base_table]['diff_from'] = [
-      'title' => t('Diff from'),
-      'help' => '',
-      'field' => [
-        'id' => 'diff__from',
-      ],
-    ];
+  foreach (\Drupal::entityTypeManager()->getDefinitions() as $entity_type) {
+    // Add the diff_from and diff_to fields to every revisionable entity type.
+    if ($entity_type->isRevisionable()) {
+      $revision_base_table = $entity_type->getRevisionDataTable() ?: $entity_type->getRevisionTable();
 
-    $data[$revision_base_table]['diff_to'] = [
-      'title' => t('Diff to'),
-      'help' => '',
-      'field' => [
-        'id' => 'diff__to',
-      ],
-    ];
+      $data[$revision_base_table]['diff_from'] = [
+        'title' => t('Diff from'),
+        'help' => '',
+        'field' => [
+          'id' => 'diff__from',
+        ],
+      ];
+      $data[$revision_base_table]['diff_to'] = [
+        'title' => t('Diff to'),
+        'help' => '',
+        'field' => [
+          'id' => 'diff__to',
+        ],
+      ];
+    }
   }
 
   return $data;
diff -u b/src/Plugin/views/field/DiffFrom.php b/src/Plugin/views/field/DiffFrom.php
--- b/src/Plugin/views/field/DiffFrom.php
+++ b/src/Plugin/views/field/DiffFrom.php
@@ -35,28 +35,22 @@
   public function viewsForm(&$form, FormStateInterface $form_state) {
     // Replace the form submit button label.
     $form['actions']['submit']['#value'] = $this->t('Compare');
-
-    $use_revision = array_key_exists('revision', $this->view->getQuery()->getEntityTableInfo());
-    if (!empty($this->view->result)) {
-      $form[$this->options['id']]['#tree'] = TRUE;
-      foreach ($this->view->result as $row_index => $row) {
-        $entity = $row->_entity;
-        $form[$this->options['id']][$row_index] = [
-          '#type' => 'radio',
-          '#parents' => [$this->options['id']],
-          '#title' => $this->t('Compare this item'),
-          '#title_display' => 'invisible',
-          '#return_value' => $this->calculateEntityDiffFormKey($entity, $use_revision),
-        ];
-      }
-    }
+    parent::viewsForm($form, $form_state);
   }
 
+  /**
+   * Returns the diff_to field ID.
+   *
+   * @return string
+   *   The diff_to field ID, or null if the field was not found on the view.
+   */
   protected function getToFieldId() {
-    $to_fields = array_filter($this->view->field, function (FieldPluginBase $field) {
-      return $field instanceof DiffTo;
-    });
-    return array_keys($to_fields)[0];
+    /** @var FieldPluginBase $field */
+    foreach ($this->view->field as $id => $field) {
+      if ($field instanceof DiffTo) {
+        return $id;
+      }
+    }
   }
 
   /**
@@ -78,12 +72,18 @@
       $diff_to = $form_state->getValue($this->getToFieldId());
       $diff_to_entity = $this->loadEntityFromDiffFormKey($diff_to);
 
+      // We need both entities, so quietly abort if neither can be loaded for
+      // any reason.
+      // TODO: Should we throw an exception instead?
+      if (empty($diff_from_entity) || empty($diff_to_entity)) {
+        return;
+      }
+
       $options = array(
         'query' => $this->getDestinationArray(),
       );
       $entity_type_id = $diff_from_entity->getEntityTypeId();
 
-
       if ($diff_from_entity instanceof NodeInterface) {
         $form_state->setRedirect('diff.revisions_diff', [$entity_type_id => $diff_from_entity->id(),'left_vid' => $diff_from_entity->getRevisionId(), 'right_vid' => $diff_to_entity->getRevisionId()], $options);
       }
diff -u b/src/Plugin/views/field/DiffPluginBase.php b/src/Plugin/views/field/DiffPluginBase.php
--- b/src/Plugin/views/field/DiffPluginBase.php
+++ b/src/Plugin/views/field/DiffPluginBase.php
@@ -7,9 +7,11 @@
 
 namespace Drupal\diff\Plugin\views\field;
 
+use Drupal\Component\Serialization\Json;
 use Drupal\Core\Entity\EntityInterface;
 use Drupal\Core\Entity\EntityTypeManagerInterface;
 use Drupal\Core\Entity\RevisionableInterface;
+use Drupal\Core\Form\FormStateInterface;
 use Drupal\Core\TypedData\TranslatableInterface;
 use Drupal\views\Plugin\views\field\FieldPluginBase;
 use Drupal\views\Plugin\views\field\UncacheableFieldHandlerTrait;
@@ -64,6 +66,12 @@
     $this->ensureMyTable();
   }
 
+  /**
+   * Returns the maximum possible age of cache items for this plugin.
+   *
+   * @return int
+   *   The maximum cache age in seconds.
+   */
   public function getCacheMaxAge() {
     return 0;
   }
@@ -76,6 +84,25 @@
   }
 
   /**
+   * {@inheritdoc}
+   */
+  public function viewsForm(&$form, FormStateInterface $form_state) {
+    if (!empty($this->view->result)) {
+      $form[$this->options['id']]['#tree'] = TRUE;
+      foreach ($this->view->result as $row_index => $row) {
+        $entity = $row->_entity;
+        $form[$this->options['id']][$row_index] = [
+          '#type' => 'radio',
+          '#parents' => [$this->options['id']],
+          '#title' => $this->t('Compare this item'),
+          '#title_display' => 'invisible',
+          '#return_value' => $this->calculateEntityDiffFormKey($entity),
+        ];
+      }
+    }
+  }
+
+  /**
    * Calculates a diff form key.
    *
    * This generates a key that is used as the checkbox return value when
@@ -101,11 +128,10 @@
     // An entity ID could be an arbitrary string (although they are typically
     // numeric). JSON then Base64 encoding ensures the diff_form_key is
     // safe to use in HTML, and that the key parts can be retrieved.
-    $key = json_encode($key_parts);
+    $key = Json::encode($key_parts);
     return base64_encode($key);
   }
 
-
   /**
    * Loads an entity based on a diff form key.
    *
@@ -119,7 +145,7 @@
    */
   protected function loadEntityFromDiffFormKey($diff_form_key) {
     $key = base64_decode($diff_form_key);
-    $key_parts = json_decode($key);
+    $key_parts = Json::decode($key);
     $revision_id = NULL;
 
     // If there are 3 items, vid will be last.
diff -u b/src/Plugin/views/field/DiffTo.php b/src/Plugin/views/field/DiffTo.php
--- b/src/Plugin/views/field/DiffTo.php
+++ b/src/Plugin/views/field/DiffTo.php
@@ -26,23 +26,2 @@
 
-  /**
-   * {@inheritdoc}
-   */
-  public function viewsForm(&$form, FormStateInterface $form_state) {
-    $use_revision = array_key_exists('revision', $this->view->getQuery()->getEntityTableInfo());
-
-    if (!empty($this->view->result)) {
-      $form[$this->options['id']]['#tree'] = TRUE;
-      foreach ($this->view->result as $row_index => $row) {
-        $entity = $row->_entity;
-        $form[$this->options['id']][$row_index] = [
-          '#type' => 'radio',
-          '#parents' => [$this->options['id']],
-          '#title' => $this->t('Compare this item'),
-          '#title_display' => 'invisible',
-          '#return_value' => $this->calculateEntityDiffFormKey($entity, $use_revision),
-        ];
-      }
-    }
-  }
-
 }
diff -u b/src/Tests/DiffViewsTest.php b/src/Tests/DiffViewsTest.php
--- b/src/Tests/DiffViewsTest.php
+++ b/src/Tests/DiffViewsTest.php
@@ -24,6 +24,9 @@
    */
   public static $modules = ['node', 'diff', 'user', 'diff_test'];
 
+  /**
+   * Tests the behavior of a view that uses the diff_from and diff_to fields.
+   */
   public function testDiffView() {
     $node_type = NodeType::create([
       'type' => 'article',
@@ -57,7 +60,7 @@
       'diff_to' => $to_second,
     ];
     $this->drupalPostForm(NULL, $edit, t('Compare'));
-    $this->assertUrl(Url::fromRoute('diff.revisions_diff', ['left_vid' => 1, 'right_vid' => 2]), ['query' => ['destination' => '/node/1/diff-views']]);
+    $this->assertUrl(Url::fromRoute('diff.revisions_diff', ['node' => $node->id(), 'left_vid' => 1, 'right_vid' => 2]), ['query' => ['destination' => '/node/1/diff-views']]);
     $this->assertRaw('<td class="diff-context diff-deletedline">Test article: <span class="diffchange">giraffe</span></td>');
     $this->assertRaw('<td class="diff-context diff-addedline">Test article: <span class="diffchange">llama</span></td>');
   }