fix: throw better error message if a user doesn't have a key even though it should have

Signed-off-by: Robin Appelman <robin@icewind.nl>

Author: icewind1991

lib/private/Config/UserConfig.php

@@ -1171,7 +1171,10 @@ private function setTypedValue(
 		}
 
 		$oldValue = null;
+		$updateReason = '';
 		if ($this->hasKey($userId, $app, $key, $lazy)) {
+			$updateReason = 'key exists';
+
 			/**
 			 * no update if key is already known with set lazy status and value is
 			 * not different, unless sensitivity is switched from false to true.
@@ -1206,6 +1209,7 @@ private function setTypedValue(
 					// TODO: throw exception or just log and returns false !?
 					throw $e;
 				}
+				$updateReason = 'inserted raised a duplicate contraint';
 			}
 		}
 
@@ -1216,7 +1220,11 @@ private function setTypedValue(
 			$currType = $this->valueDetails[$userId][$app][$key]['type'] ?? null;
 			if ($currType === null) { // this might happen when switching lazy loading status
 				$this->loadConfigAll($userId);
-				$currType = $this->valueDetails[$userId][$app][$key]['type'];
+
+				if (!isset($this->valueDetails[$userId][$app][$key])) {
+					throw new UnknownKeyException("unknown key $app $key for $userId even though $updateReason");
+				}
+				$currType = $this->valueDetails[$userId][$app][$key]['type'] ?? null;
 			}
 
 			/**