Issue #3015199: Allow SkipOnValue to include a message in the MigrateSkipRowException.

Closes #3015199

src/Plugin/migrate/process/SkipOnValue.php

@@ -24,6 +24,9 @@ use Drupal\migrate\Row;
  *   configuration key value. Possible values:
  *   - row: Skips the entire row.
  *   - process: Prevents further processing of the input property
+ * - message: (optional) A message to be logged in the {migrate_message_*} table
+ *   for this row. Messages are only logged for the 'row' method. If not set,
+ *   nothing is logged in the message table.
  *
  * @codingStandardsIgnoreStart
  *
@@ -50,9 +53,11 @@ use Drupal\migrate\Row;
  *     value:
  *       - article
  *       - testimonial
+ *     message: 'Not an article nor a testimonial content type'
  * @endcode
  * The above example will skip processing any row for which the source row's
- * content type field is not "article" or "testimonial".
+ * content type field is not "article" or "testimonial", and log the message 'Not
+ * an article nor a testimonial content type' to the message table.
  *
  * @codingStandardsIgnoreEnd
  */
@@ -65,7 +70,6 @@ class SkipOnValue extends ProcessPluginBase {
     if (empty($configuration['value']) && !array_key_exists('value', $configuration)) {
       throw new \InvalidArgumentException('Skip on value plugin is missing value configuration.');
     }
-
     parent::__construct($configuration, $plugin_id, $plugin_definition);
   }
 
@@ -73,6 +77,8 @@ class SkipOnValue extends ProcessPluginBase {
    * {@inheritdoc}
    */
   public function row($value, MigrateExecutableInterface $migrate_executable, Row $row, $destination_property) {
+    $message = !empty($this->configuration['message']) ? $this->configuration['message'] : '';
+
     if (is_array($this->configuration['value'])) {
       $value_in_array = FALSE;
       $not_equals = isset($this->configuration['not_equals']);
@@ -82,11 +88,11 @@ class SkipOnValue extends ProcessPluginBase {
       }
 
       if (($not_equals && !$value_in_array) || (!$not_equals && $value_in_array)) {
-        throw new MigrateSkipRowException();
+        throw new MigrateSkipRowException($message);
       }
     }
     elseif ($this->compareValue($value, $this->configuration['value'], !isset($this->configuration['not_equals']))) {
-      throw new MigrateSkipRowException();
+      throw new MigrateSkipRowException($message);
     }
 
     return $value;