fix: null-safe dereferencing of record-typed variables fields via the…

… `<fieldValue>` operand
oat-sa · Jan 20, 2025 · dba0c71 · dba0c71
1 parent 2336405
commit dba0c71
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Showing 2 changed files with 16 additions and 10 deletions.
diff --git a/src/qtism/runtime/expressions/operators/FieldValueProcessor.php b/src/qtism/runtime/expressions/operators/FieldValueProcessor.php
@@ -24,6 +24,7 @@
 namespace qtism\runtime\expressions\operators;
 
 use qtism\data\expressions\operators\FieldValue;
+use qtism\runtime\common\RecordContainer;
 
 /**
  * The FieldValueProcessor class aims at processing FieldValue expressions.
@@ -45,16 +46,20 @@ class FieldValueProcessor extends OperatorProcessor
     #[\ReturnTypeWillChange]
     public function process()
     {
-        $operands = $this->getOperands();
+        $operand = $this->getOperands()[0];
 
-        if ($operands->exclusivelyRecord() === false) {
+        if ($operand === null) {
+            return null;
+        }
+
+        if (!$operand instanceof RecordContainer) {
             $msg = 'The FieldValue operator only accepts operands with a cardinality of record.';
             throw new OperatorProcessingException($msg, $this, OperatorProcessingException::WRONG_CARDINALITY);
         }
 
         $fieldIdentifier = $this->getExpression()->getFieldIdentifier();
 
-        return $operands[0][$fieldIdentifier];
+        return $operand[$fieldIdentifier];
     }
 
     /**

diff --git a/test/qtismtest/runtime/expressions/operators/FieldValueProcessorTest.php b/test/qtismtest/runtime/expressions/operators/FieldValueProcessorTest.php
@@ -5,6 +5,7 @@
 use qtism\common\datatypes\QtiInteger;
 use qtism\common\datatypes\QtiPoint;
 use qtism\common\enums\BaseType;
+use qtism\data\expressions\Expression;
 use qtism\data\QtiComponent;
 use qtism\data\storage\xml\marshalling\MarshallerNotFoundException;
 use qtism\runtime\common\MultipleContainer;
@@ -24,7 +25,7 @@ public function testNotEnoughOperands(): void
         $expression = $this->createFakeExpression();
         $operands = new OperandsCollection();
         $this->expectException(ExpressionProcessingException::class);
-        $processor = new FieldValueProcessor($expression, $operands);
+        new FieldValueProcessor($expression, $operands);
     }
 
     public function testTooMuchOperands(): void
@@ -34,7 +35,7 @@ public function testTooMuchOperands(): void
         $operands[] = new RecordContainer();
         $operands[] = new RecordContainer();
         $this->expectException(ExpressionProcessingException::class);
-        $processor = new FieldValueProcessor($expression, $operands);
+        new FieldValueProcessor($expression, $operands);
     }
 
     public function testNullOne(): void
@@ -55,9 +56,9 @@ public function testNullTwo(): void
         $operands = new OperandsCollection();
         // null value as operand.
         $operands[] = null;
-        $this->expectException(ExpressionProcessingException::class);
         $processor = new FieldValueProcessor($expression, $operands);
         $result = $processor->process();
+        $this::assertNull($result);
     }
 
     public function testWrongCardinalityOne(): void
@@ -68,7 +69,7 @@ public function testWrongCardinalityOne(): void
         $operands[] = new QtiInteger(10);
         $processor = new FieldValueProcessor($expression, $operands);
         $this->expectException(ExpressionProcessingException::class);
-        $result = $processor->process();
+        $processor->process();
     }
 
     public function testWrongCardinalityTwo(): void
@@ -79,7 +80,7 @@ public function testWrongCardinalityTwo(): void
         $operands[] = new QtiPoint(1, 2);
         $processor = new FieldValueProcessor($expression, $operands);
         $this->expectException(ExpressionProcessingException::class);
-        $result = $processor->process();
+        $processor->process();
     }
 
     public function testWrongCardinalityThree(): void
@@ -91,7 +92,7 @@ public function testWrongCardinalityThree(): void
         // Wrong container (Multiple, Ordered)
         $processor = new FieldValueProcessor($expression, $operands);
         $this->expectException(ExpressionProcessingException::class);
-        $result = $processor->process();
+        $processor->process();
     }
 
     public function testFieldValue(): void
@@ -116,7 +117,7 @@ public function testFieldValue(): void
      * @return QtiComponent
      * @throws MarshallerNotFoundException
      */
-    public function createFakeExpression($identifier = ''): QtiComponent
+    public function createFakeExpression($identifier = ''): Expression
     {
         // The following XML Component creation
         // underlines the need of a <record> operator... :)