fix: overloading behaviour

features/access.feature

@@ -33,3 +33,11 @@ Feature: Session access
   Scenario: Iterate over non-populated session
     When data does not exist
     Then data is not iterated
+  Scenario: Overload existing array
+    When empty array for overload exists
+    Then overloading using property access succeeds
+    And overloading using property access succeeds
+  Scenario: Overload non existing array
+    When data does not exist
+    Then overloading using array access fails
+    And overloading using property access fails

src/Session.php

@@ -8,6 +8,7 @@
 use Countable;
 use ArrayAccess;
 use RuntimeException;
+use Stringable;
 
 class Session implements ArrayAccess, Iterator, Countable
 {
@@ -46,13 +47,17 @@ public function __construct(string $name, ?string $id = null, array $contents =
      *
      * @throws RuntimeException if not initialized
      */
-    public function __get(string $name)
+    public function &__get(string $name)
     {
         if (!$this->isInitialized()) {
             throw new RuntimeException('Session not initialized');
         }
 
-        // @phpstan-ignore-next-line
+        if(!isset($this->contents[$name])){
+            \trigger_error("Array key not found: '$name'", \E_USER_NOTICE);
+            return null;
+        }
+
         return $this->contents[$name];
     }
 
@@ -133,13 +138,20 @@ public function offsetUnset($name): void
         unset($this->contents[$name]);
     }
 
-    public function offsetGet($name): mixed
+    public function &offsetGet($name): mixed
     {
         if (!$this->isInitialized()) {
             throw new RuntimeException('Session not initialized');
         }
 
-        // @phpstan-ignore-next-line
+
+        if(!isset($this->contents[$name])){
+            if($name === null || \is_scalar($name) || $name instanceof Stringable){
+                \trigger_error("Array key not found: '$name'", \E_USER_NOTICE);
+            }
+            return null;
+        }
+
         return $this->contents[$name];
     }
 

tests/behavior/AccessContext.php

@@ -34,6 +34,16 @@ public function dataExists(): void
         Assert::assertCount(1, $this->session);
     }
 
+    /**
+     * @When empty array for overload exists
+     */
+    public function emptyArrayForOverloadExists(): void
+    {
+        $this->session = new Session('foo', 'bar', ['foo' => []]);
+        Assert::assertTrue($this->session->isWriteable());
+        Assert::assertCount(1, $this->session);
+    }
+
     /**
      * @Then property check returns false
      */
@@ -199,4 +209,58 @@ public function iteratorFails(): void
 
         Assert::assertSame(0, $counter);
     }
+
+    /**
+     * @Then overloading using array access succeeds
+     */
+    public function arrayOverloadSucceeds(): void
+    {
+        // @phpstan-ignore-next-line
+        $this->session['foo'][] = 'baz';
+        // @phpstan-ignore-next-line
+        Assert::assertSame('baz', $this->session['foo'][0]);
+    }
+
+    /**
+     * @Then overloading using property access succeeds
+     */
+    public function objectOverloadSucceeds(): void
+    {
+        // @phpstan-ignore-next-line
+        $this->session->foo[] = 'baz';
+        // @phpstan-ignore-next-line
+        Assert::assertSame('baz', $this->session->foo[0]);
+    }
+
+    /**
+     * @Then overloading using array access fails
+     */
+    public function arrayOverloadFails(): void
+    {
+        try {
+            $errorThrown = false;
+            // @phpstan-ignore-next-line
+            $this->session['foo'][] = 'baz';
+        } catch (Throwable $e) {
+            $errorThrown = true;
+        } finally {
+            Assert::assertTrue($errorThrown);
+        }
+    }
+
+    /**
+     * @Then overloading using property access fails
+     */
+    public function objectOverloadFails(): void
+    {
+        try {
+            $errorThrown = false;
+            // @phpstan-ignore-next-line
+            $this->session->foo[] = 'baz';
+        } catch (Throwable $e) {
+            $errorThrown = true;
+        } finally {
+            Assert::assertTrue($errorThrown);
+        }
+    }
 }