feature #30902 [Workflow] The TransitionEvent is able to modify the context (lyrixx)

This PR was merged into the 4.3-dev branch.

Discussion
----------

[Workflow] The TransitionEvent is able to modify the context

| Q             | A
| ------------- | ---
| Branch?       | master
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets |
| License       | MIT
| Doc PR        |

EUFOSSA

ping @HeahDude

Commits
-------

62ab775154 [Workflow] The TransitionEvent is able to modify the context

src/Symfony/Component/Workflow/CHANGELOG.md

@@ -6,6 +6,7 @@ CHANGELOG
 
  * Trigger `entered` event for subject entering in the Workflow for the first time.
  * Added a context to `Workflow::apply()`. The `MethodMarkingStore` could be used to leverage this feature.
+ * The `TransitionEvent` is able to modify the context.
  * Add style to transitions by declaring metadata:
 
     use Symfony\Component\Workflow\Definition;

src/Symfony/Component/Workflow/Event/TransitionEvent.php

@@ -13,4 +13,15 @@ namespace Symfony\Component\Workflow\Event;
 
 class TransitionEvent extends Event
 {
+    private $context;
+
+    public function setContext(array $context)
+    {
+        $this->context = $context;
+    }
+
+    public function getContext(): array
+    {
+        return $this->context;
+    }
 }

src/Symfony/Component/Workflow/Tests/Subject.php

@@ -5,10 +5,12 @@ namespace Symfony\Component\Workflow\Tests;
 final class Subject
 {
     private $marking;
+    private $context;
 
     public function __construct($marking = null)
     {
         $this->marking = $marking;
+        $this->context = [];
     }
 
     public function getMarking()
@@ -16,8 +18,14 @@ final class Subject
         return $this->marking;
     }
 
-    public function setMarking($marking)
+    public function setMarking($marking, array $context = [])
     {
         $this->marking = $marking;
+        $this->context = $context;
+    }
+
+    public function getContext(): array
+    {
+        return $this->context;
     }
 }

src/Symfony/Component/Workflow/Tests/WorkflowTest.php

@@ -7,6 +7,7 @@ use Symfony\Component\EventDispatcher\EventDispatcher;
 use Symfony\Component\Workflow\Definition;
 use Symfony\Component\Workflow\Event\Event;
 use Symfony\Component\Workflow\Event\GuardEvent;
+use Symfony\Component\Workflow\Event\TransitionEvent;
 use Symfony\Component\Workflow\Exception\NotEnabledTransitionException;
 use Symfony\Component\Workflow\Marking;
 use Symfony\Component\Workflow\MarkingStore\MarkingStoreInterface;
@@ -418,6 +419,21 @@ class WorkflowTest extends TestCase
         $this->assertSame($eventNameExpected, $eventDispatcher->dispatchedEvents);
     }
 
+    public function testApplyWithContext()
+    {
+        $definition = $this->createComplexWorkflowDefinition();
+        $subject = new Subject();
+        $eventDispatcher = new EventDispatcher();
+        $eventDispatcher->addListener('workflow.transition', function (TransitionEvent $event) {
+            $event->setContext(array_merge($event->getContext(), ['user' => 'admin']));
+        });
+        $workflow = new Workflow($definition, new MethodMarkingStore(), $eventDispatcher);
+
+        $workflow->apply($subject, 't1', ['foo' => 'bar']);
+
+        $this->assertSame(['foo' => 'bar', 'user' => 'admin'], $subject->getContext());
+    }
+
     public function testEventName()
     {
         $definition = $this->createComplexWorkflowDefinition();

src/Symfony/Component/Workflow/Workflow.php

@@ -176,7 +176,7 @@ class Workflow implements WorkflowInterface
 
             $this->leave($subject, $transition, $marking);
 
-            $this->transition($subject, $transition, $marking);
+            $context = $this->transition($subject, $transition, $marking, $context);
 
             $this->enter($subject, $transition, $marking);
 
@@ -308,17 +308,20 @@ class Workflow implements WorkflowInterface
         }
     }
 
-    private function transition($subject, Transition $transition, Marking $marking): void
+    private function transition($subject, Transition $transition, Marking $marking, array $context): array
     {
         if (null === $this->dispatcher) {
-            return;
+            return $context;
         }
 
         $event = new TransitionEvent($subject, $marking, $transition, $this);
+        $event->setContext($context);
 
         $this->dispatcher->dispatch($event, WorkflowEvents::TRANSITION);
         $this->dispatcher->dispatch($event, sprintf('workflow.%s.transition', $this->name));
         $this->dispatcher->dispatch($event, sprintf('workflow.%s.transition.%s', $this->name, $transition->getName()));
+
+        return $event->getContext();
     }
 
     private function enter($subject, Transition $transition, Marking $marking): void