[BUGFIX] Prevent memory leak when fetching a lot of database records

When fetching a lot of records from database the memory is nearly
doubled in the fetchAll function. It seems php keeps references or
creates an array copy that could not be garbage collected. Enforcing
a manuell gc_collect_cycles does not help either.

Resolves: #102986
Releases: main, 12.4, 11.5
Change-Id: I2da5f1e0126aa1dc867c8fb3074be4a11491f8f3
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/82725


Tested-by: core-ci <typo3@b13.com>
Reviewed-by: Benjamin Franzke <ben@bnf.dev>
Tested-by: Benjamin Franzke <ben@bnf.dev>

typo3/sysext/core/Classes/Database/Driver/DriverResult.php

@@ -156,15 +156,11 @@ class DriverResult implements ResultInterface
     protected function mapResourceToString($record)
     {
         if (is_array($record)) {
-            return array_map(
-                static function ($value) {
-                    if (is_resource($value)) {
-                        $value = stream_get_contents($value);
-                    }
-                    return $value;
-                },
-                $record
-            );
+            foreach ($record as $k => $value) {
+                if (is_resource($value)) {
+                    $record[$k] = stream_get_contents($value);
+                }
+            }
         }
 
         return $record;