Preventing execution boxes to be optimized.

Author: Martin Krulis

app/helpers/ExerciseConfig/Compilation/BoxesOptimizer.php

@@ -79,6 +79,11 @@ private static function canNodesBeOptimized(Node $first, Node $second): bool {
       return false;
     }
 
+    // check whether both boxes can be optimized
+    if (!$firstBox->isOptimizable() || !$secondBox->isOptimizable()) {
+      return false;
+    }
+
     // check ports counts
     if (count($firstBox->getInputPorts()) !== count($secondBox->getInputPorts()) ||
         count($firstBox->getOutputPorts()) !== count($secondBox->getOutputPorts())) {

app/helpers/ExerciseConfig/Pipeline/Box/Box.php

@@ -77,6 +77,17 @@ public abstract function getType(): string;
    */
   public abstract function getCategory(): string;
 
+
+  /**
+   * Whether the box can be optimized (merged with another box with equal functionality).
+   * Boxes are optimizable by default, but specific boxes may prevent this behavior if necessary.
+   * @return bool
+   */
+  public function isOptimizable(): bool
+  {
+    return true;
+  }
+
   /**
    * Compile box into set of low-level tasks.
    * @param CompilationParams $params

app/helpers/ExerciseConfig/Pipeline/Box/Boxes/base/ExecutionBox.php

@@ -45,6 +45,11 @@ public function getCategory(): string {
     return BoxCategories::$EXECUTION;
   }
 
+  public function isOptimizable(): bool
+  {
+    return false; // execution boxes are not optimizable, all executions must be performed
+  }
+
   /**
    * Base compilation which creates task, set its type to execution and create
    * sandbox configuration. Stdin and stdout are also handled here.