[PHP 8.4] Fixes for implicit nullability deprecation (#1297)

Author: andypost

Propagation/NoopTextMapPropagator.php

@@ -25,12 +25,12 @@ public function fields(): array
         return [];
     }
 
-    public function extract($carrier, PropagationGetterInterface $getter = null, ContextInterface $context = null): ContextInterface
+    public function extract($carrier, ?PropagationGetterInterface $getter = null, ?ContextInterface $context = null): ContextInterface
     {
         return $context ?? Context::getCurrent();
     }
 
-    public function inject(&$carrier, PropagationSetterInterface $setter = null, ContextInterface $context = null): void
+    public function inject(&$carrier, ?PropagationSetterInterface $setter = null, ?ContextInterface $context = null): void
     {
     }
 }

Propagation/TextMapPropagatorInterface.php

@@ -26,13 +26,13 @@ public function fields() : array;
      *
      * @see https://github.com/open-telemetry/opentelemetry-specification/blob/v1.6.1/specification/context/api-propagators.md#textmap-inject
      */
-    public function inject(mixed &$carrier, PropagationSetterInterface $setter = null, ContextInterface $context = null): void;
+    public function inject(mixed &$carrier, ?PropagationSetterInterface $setter = null, ?ContextInterface $context = null): void;
 
     /**
      * Extracts specific values from the provided carrier into the provided {@see ContextInterface}
      * via an {@see PropagationGetterInterface}.
      *
      * @see https://github.com/open-telemetry/opentelemetry-specification/blob/v1.6.1/specification/context/api-propagators.md#textmap-extract
      */
-    public function extract($carrier, PropagationGetterInterface $getter = null, ContextInterface $context = null): ContextInterface;
+    public function extract($carrier, ?PropagationGetterInterface $getter = null, ?ContextInterface $context = null): ContextInterface;
 }