Refactor obtaining discriminator values for a class

src/Mapping/ClassMetadata.php

@@ -2199,6 +2199,35 @@ public function addDiscriminatorMapClass(int|string $name, string $className): v
         $this->addSubClass($className);
     }
 
+    /**
+     * @internal
+     *
+     * @return list<int|string>
+     *
+     * @psalm-internal Doctrine\ORM
+     */
+    public function getDiscriminatorValuesForClassAndSubclasses(): array
+    {
+        $values       = [];
+        $valueByClass = array_flip($this->discriminatorMap);
+
+        // Even if this class is part of an inheritance hierarchy, the discriminator
+        // value may be null in case the class is abstract.
+        if ($this->discriminatorValue !== null) {
+            $values[] = $this->discriminatorValue;
+        }
+
+        foreach ($this->subClasses as $subClass) {
+            // Abstract entity classes show up in the list of subClasses,
+            // but may be omitted from the discriminator map.
+            if (isset($valueByClass[$subClass])) {
+                $values[] = $valueByClass[$subClass];
+            }
+        }
+
+        return $values;
+    }
+
     /** @param array<class-string> $classes */
     public function addSubClasses(array $classes): void
     {

src/Persisters/Entity/SingleTablePersister.php

@@ -10,10 +10,7 @@
 use Doctrine\ORM\Mapping\ClassMetadata;
 use Doctrine\ORM\Utility\PersisterHelper;
 
-use function array_flip;
-use function array_intersect;
 use function array_map;
-use function array_unshift;
 use function implode;
 use function strval;
 
@@ -138,19 +135,12 @@ protected function getSelectConditionCriteriaSQL(Criteria $criteria): string
 
     protected function getSelectConditionDiscriminatorValueSQL(): string
     {
-        $values = array_map($this->conn->quote(...), array_map(
-            strval(...),
-            array_flip(array_intersect($this->class->discriminatorMap, $this->class->subClasses)),
-        ));
-
-        if ($this->class->discriminatorValue !== null) { // discriminators can be 0
-            array_unshift($values, $this->conn->quote((string) $this->class->discriminatorValue));
-        }
-
+        $tableAlias     = $this->getSQLTableAlias($this->class->name);
         $discColumnName = $this->class->getDiscriminatorColumn()->name;
-
-        $values     = implode(', ', $values);
-        $tableAlias = $this->getSQLTableAlias($this->class->name);
+        $values         = implode(', ', array_map(
+            $this->conn->quote(...),
+            array_map(strval(...), $this->class->getDiscriminatorValuesForClassAndSubclasses())
+        ));
 
         return $tableAlias . '.' . $discColumnName . ' IN (' . $values . ')';
     }

src/Query/SqlWalker.php

@@ -368,6 +368,7 @@ private function generateOrderedCollectionOrderByItems(): string
     private function generateDiscriminatorColumnConditionSQL(array $dqlAliases): string
     {
         $sqlParts = [];
+        $conn     = $this->em->getConnection();
 
         foreach ($dqlAliases as $dqlAlias) {
             $class = $this->getMetadataForDqlAlias($dqlAlias);
@@ -376,22 +377,20 @@ private function generateDiscriminatorColumnConditionSQL(array $dqlAliases): str
                 continue;
             }
 
-            $conn   = $this->em->getConnection();
-            $values = [];
-
-            if ($class->discriminatorValue !== null) { // discriminators can be 0
-                $values[] = $conn->quote($class->discriminatorValue);
-            }
-
-            foreach ($class->subClasses as $subclassName) {
-                $values[] = $conn->quote((string) $this->em->getClassMetadata($subclassName)->discriminatorValue);
-            }
-
             $sqlTableAlias = $this->useSqlTableAliases
                 ? $this->getSQLTableAlias($class->getTableName(), $dqlAlias) . '.'
                 : '';
 
-            $sqlParts[] = $sqlTableAlias . $class->getDiscriminatorColumn()->name . ' IN (' . implode(', ', $values) . ')';
+            $discriminatorValues = array_map(
+                $conn->quote(...),
+                array_map(strval(...), $class->getDiscriminatorValuesForClassAndSubclasses())
+            );
+
+            if ($discriminatorValues !== []) {
+                $sqlParts[] = $sqlTableAlias . $class->getDiscriminatorColumn()->name . ' IN (' . implode(', ', $discriminatorValues) . ')';
+            } else {
+                $sqlParts[] = '1=0'; // impossible condition
+            }
         }
 
         $sql = implode(' AND ', $sqlParts);