Merge pull request #671 from jameshulse/patch-1

Backport cache fix to v3

Author: rubenvanassche

src/Support/Caching/CachedDataConfig.php

@@ -20,7 +20,21 @@ public function __construct()
 
     public function getDataClass(string $class): DataClass
     {
-        return $this->cache?->getDataClass($class) ?? parent::getDataClass($class);
+        if (array_key_exists($class, $this->dataClasses)) {
+            return $this->dataClasses[$class];
+        }
+
+        if ($this->cache === null) {
+            return parent::getDataClass($class);
+        }
+
+        $dataClass = $this->cache->getDataClass($class);
+
+        if ($dataClass === null) {
+            return parent::getDataClass($class);
+        }
+
+        return $this->dataClasses[$class] = $dataClass;
     }
 
     public function setCache(DataStructureCache $cache): self