EntityQuery PHP issue when assigning the query to a variable

Question

I am very confused about this behavior of EntityQuery, or maybe I am just missing something basic about PHP.

Here is the query I am working with:

$entity_query_points1 = \Drupal::entityQuery($entity_type_id)
  ->condition($entity_type->getKey('bundle'), $entity_type_bundle)
  ->condition($entity_type->getKey('uid'), $uid)
  ->condition('field_int_points', 1, '=');
return $entity_query_points1;

This is fine.

But if this query returns no results, I wanted to immediately execute another query. So I made a switch statement and wrote code like this:

$entity_query_points1 = \Drupal::entityQuery($entity_type_id)
  ->condition($entity_type->getKey('bundle'), $entity_type_bundle)
  ->condition($entity_type->getKey('uid'), $uid)
  ->condition('field_int_points', 1, '=');
$entity_query = $entity_query_points1;
$count = $entity_query->count()->execute();
if ($count >= 1) {
  return $entity_query_points1;
}

This fails with a WSOD (I am using this code with the JSON:API Resources module):

TypeError: Argument 2 passed to Drupal\jsonapi_resources\Resource\EntityQueryResourceBase::loadResourceObjectsByEntityIds() must be of the type array, string given, called in /app/web/modules/contrib/jsonapi_resources/src/Resource/EntityQueryResourceBase.php on line 97 in Drupal\jsonapi_resources\Resource\EntityQueryResourceBase->loadResourceObjectsByEntityIds() (line 125 of modules/contrib/jsonapi_resources/src/Resource/EntityQueryResourceBase.php).

If I use the following code, it works (query resolved correctly, no WSOD):

$entity_query_points1 = \Drupal::entityQuery($entity_type_id)
  ->condition($entity_type->getKey('bundle'), $entity_type_bundle)
  ->condition($entity_type->getKey('uid'), $uid)
  ->condition('field_int_points', 1, '=');
$entity_query = $entity_query_points1;
$count = $entity_query->count()->execute();
if ($count >= 1) {
  $entity_query_score1 = \Drupal::entityQuery($entity_type_id)
    ->condition($entity_type->getKey('bundle'), $entity_type_bundle)
    ->condition($entity_type->getKey('uid'), $uid)
    ->condition('field_int_points', 1, '=');
  return $entity_query_points1;
}

But... why? I executed the count on $entity_query, but I have to redefine $entity_query_score1 to return the query as expected. I know having to redefine the query means I have screwed up somehow, but I don't know what my mistake is.

Answer 1

Objects work differently than regular variables in PHP. They are "assigned by reference", generally speaking. The Objects and References page in the PHP manual goes into some detail about this. Basically, your = is not working as you expect. $entity_query and $entity_query_points1 are "the same object".

As noted by @baikho in the comments, you'll need to use clone to achieve what you're trying to do.

$entity_query = clone $entity_query_points1;