EntityQuery AND condition groups do not work for fields with unlimited cardinality after #2875033

Problem/Motivation

#2875033 optimized joins and table selection in the SQL entity query implementation.

As part of that change, special handling was added for multi-value fields used in separate andConditionGroup()conditions. Separate condition groups need separate joins so that different values can be matched on different items of the same multi-value field.

For example:

$query = \Drupal::entityTypeManager()
  ->getStorage('node')
  ->getQuery()
  ->accessCheck(FALSE);

$query->condition(
  $query->andConditionGroup()
    ->condition('field_tags.target_id', $tag1_tid)
);

$query->condition(
  $query->andConditionGroup()
    ->condition('field_tags.target_id', $tag2_tid)
);

$result = $query->execute();

This should find entities where field_tags contains both $tag1_tid and $tag2_tid.

The implementation added by #2875033 contains the following condition in Drupal\Core\Entity\Query\Sql\Tables:

if ($index_prefix === '' && $field_storage->getCardinality() > 1) {
  $index_prefix = $condition_prefix;
}

This works when a multi-value field has a finite cardinality greater than 1, for example 2, 3, etc.

However, it does not work when the field has unlimited cardinality.

Drupal represents unlimited cardinality using:

FieldStorageDefinitionInterface::CARDINALITY_UNLIMITED

which has the value `-1`.

Therefore:

$field_storage->getCardinality() > 1

evaluates to FALSE for an unlimited field.

As a result, an unlimited field is not treated as multi-value by this logic. The same field table alias can be reused for separate andConditionGroup() conditions instead of creating the separate joins required to match values on different field items.

This causes an EntityQuery that should match entities containing both values to return no results.

This appears to be a regression introduced by #2875033.

Steps to reproduce

1. Create a content type with a multi-value entity reference field, for example field_tags.
2. Set the field cardinality to **Unlimited**.
3. Create an entity where field_tags contains two different values, for example term IDs 1 and 2.
4. Execute an EntityQuery using separate andConditionGroup() conditions:

$query = \Drupal::entityTypeManager()
  ->getStorage('node')
  ->getQuery()
  ->accessCheck(FALSE);

$query->condition(
  $query->andConditionGroup()
    ->condition('field_tags.target_id', 1)
);

$query->condition(
  $query->andConditionGroup()
    ->condition('field_tags.target_id', 2)
);

$result = $query->execute();

5. Observe that the query does not create separate joins for the two conditions and the entity is not returned.
6. Change the field cardinality from Unlimited to a finite value greater than 1.
7. Run the same query again.
8. Observe that separate joins are generated and the entity is returned as expected.

Proposed resolution

Use the field storage definition's isMultiple() method instead of checking whether the cardinality is greater than 1.

Change:

if ($index_prefix === '' && $field_storage->getCardinality() > 1) {
  $index_prefix = $condition_prefix;
}

to:

if ($index_prefix === '' && $field_storage->isMultiple()) {
  $index_prefix = $condition_prefix;
}

isMultiple() correctly handles both finite multi-value cardinalities and CARDINALITY_UNLIMITED.

Add test coverage for separate andConditionGroup() conditions on a field whose cardinality is FieldStorageDefinitionInterface::CARDINALITY_UNLIMITED.