FEATURE: Introduce EEL tracer for handling Neos9 deprecations

Neos.Eel/Classes/Context.php

@@ -26,17 +26,13 @@
  */
 class Context
 {
-    /**
-     * @var mixed
-     */
-    protected $value;
-
     /**
      * @param mixed $value
      */
-    public function __construct($value = null)
-    {
-        $this->value = $value;
+    public function __construct(
+        protected mixed $value = null,
+        private ?EelInvocationTracerInterface $tracer = null
+    ) {
     }
 
     /**
@@ -62,6 +58,7 @@ public function get($path)
             if (is_array($this->value)) {
                 return array_key_exists($path, $this->value) ? $this->value[$path] : null;
             } elseif (is_object($this->value)) {
+                $this->tracer?->recordPropertyAccess($this->value, $path);
                 try {
                     return ObjectAccess::getProperty($this->value, $path);
                 } catch (PropertyNotAccessibleException $exception) {
@@ -115,6 +112,14 @@ public function call($method, array $arguments = [])
                 $arguments[$i] = $arguments[$i]->unwrap();
             }
         }
+        if ($this->tracer !== null) {
+            // optional experimental tracing
+            if (is_object($this->value)) {
+                $this->tracer->recordMethodCall($this->value, $method, $arguments);
+            } else {
+                $this->tracer->recordFunctionCall($callback, $method, $arguments);
+            }
+        }
         return call_user_func_array($callback, $arguments);
     }
 
@@ -139,7 +144,7 @@ public function callAndWrap($method, array $arguments = [])
     public function wrap($value)
     {
         if (!$value instanceof Context) {
-            return new static($value);
+            return new static($value, $this->tracer);
         } else {
             return $value;
         }

Neos.Eel/Classes/EelInvocationTracerInterface.php

@@ -0,0 +1,21 @@
+<?php
+
+namespace Neos\Eel;
+
+/**
+ * @internal experimental tracer for eel. Could be used for example to collect and log deprecations.
+ */
+interface EelInvocationTracerInterface
+{
+    public function recordPropertyAccess(object $object, string $propertyName): void;
+
+    /**
+     * @param array<int, mixed> $arguments
+     */
+    public function recordMethodCall(object $object, string $methodName, array $arguments): void;
+
+    /**
+     * @param array<int, mixed> $arguments
+     */
+    public function recordFunctionCall(callable $function, string $functionName, array $arguments): void;
+}

Neos.Eel/Classes/Utility.php

@@ -90,7 +90,7 @@ private static function createClosureFromConfiguration(string $objectConfigurati
      * @return mixed
      * @throws Exception
      */
-    public static function evaluateEelExpression($expression, EelEvaluatorInterface $eelEvaluator, array $contextVariables, array $defaultContextConfiguration = [])
+    public static function evaluateEelExpression($expression, EelEvaluatorInterface $eelEvaluator, array $contextVariables, array $defaultContextConfiguration = [], ?EelInvocationTracerInterface $tracer = null)
     {
         $eelExpression = self::parseEelExpression($expression);
         if ($eelExpression === null) {
@@ -100,7 +100,7 @@ public static function evaluateEelExpression($expression, EelEvaluatorInterface
         $defaultContextVariables = self::getDefaultContextVariables($defaultContextConfiguration);
         $contextVariables = array_merge($defaultContextVariables, $contextVariables);
 
-        $context = new ProtectedContext($contextVariables);
+        $context = new ProtectedContext($contextVariables, $tracer);
         $context->allow('q');
 
         // Allow functions on the uppermost context level to allow calling them without