[TASK] Make getInstanceIdentifier() and getInstancePath() non-static

Convert protected static methods to protected instance methods and
mark as @internal. This allows subclasses to override these methods
for test isolation in parallel execution (Paratest), without making
them part of the public API.

Fixes: #708

Author: dkd-kaehm

Classes/Core/Functional/FunctionalTestCase.php

@@ -284,8 +284,8 @@ protected function setUp(): void
             self::markTestSkipped('Functional tests must be called through phpunit on CLI');
         }
 
-        $this->identifier = self::getInstanceIdentifier();
-        $this->instancePath = self::getInstancePath();
+        $this->identifier = $this->getInstanceIdentifier();
+        $this->instancePath = $this->getInstancePath();
         putenv('TYPO3_PATH_ROOT=' . $this->instancePath);
         putenv('TYPO3_PATH_APP=' . $this->instancePath);
 
@@ -1098,21 +1098,23 @@ protected function withDatabaseSnapshot(?callable $createCallback = null, ?calla
     }
 
     /**
-     * Uses a 7 char long hash of class name as identifier.
+     * Create a 7 char long hash of class name as identifier.
      *
+     * @internal
      * @return non-empty-string
      */
-    protected static function getInstanceIdentifier(): string
+    protected function getInstanceIdentifier(): string
     {
         return substr(sha1(static::class), 0, 7);
     }
 
     /**
+     * @internal Extensions functional tests should usually not fiddle with this. This may break anytime.
      * @return non-empty-string
      */
-    protected static function getInstancePath(): string
+    protected function getInstancePath(): string
     {
-        $identifier = self::getInstanceIdentifier();
+        $identifier = $this->getInstanceIdentifier();
         return ORIGINAL_ROOT . 'typo3temp/var/tests/functional-' . $identifier;
     }
 }