SolrConnectorPluginBase leaks Solarium\Client instances on re-instantiation

Setup

• Solr version: 8.11.3
• Drupal Core version: 11.3.5
• Search API version: 1.40.0
• Search API Solr version: 4.3.10
• Configured Solr Connector: standard

Issue

SolrConnectorPluginBase::connect() creates a new Solarium\Client each time the connector is reinstantiated, but the old client is never freed. In long-lived PHP processes such as a full Behat test suite run, Solarium\Client instances accumulate indefinitely in memory and are never garbage-collected.

Solarium\Plugin\CustomizeRequest registers itself as a listener on the injected event dispatcher when first used, creating a circular reference: event dispatcher → CustomizeRequest → Solarium\Client → event dispatcher

PHP's reference counting cannot break this cycle, so every discarded client stays in memory for the lifetime of the process. In long-lived processes (Behat, Drush, migrations), this causes unbounded accumulation.

Proposed resolution

Implement __destruct() on SolrConnectorPluginBase to call Client::removePlugin()` on each plugin, which triggers deinitPlugin() and removes the listener, breaking the cycle:

public function __destruct() {
  if ($this->solr) {
    foreach (array_keys($this->solr->getPlugins()) as $key) {
      $this->solr->removePlugin($key);
    }
  }
}