Fixed PHP IteratorAggregate, ArrayAccess and Countable-related deprec…

…ation notices

- Ping #164

(cherry picked from commit 37ed4ab36bb6e43f71010245850b8940c21682f6)

CheckoutManager.php

@@ -194,22 +194,22 @@ public function dimension(): ?Dimension
         return $this->store->dimension();
     }
 
-    public function offsetExists(mixed $offset)
+    public function offsetExists(mixed $offset): bool
     {
         return $this->store->offsetExists($offset);
     }
 
-    public function offsetGet(mixed $offset)
+    public function offsetGet(mixed $offset): mixed
     {
         return $this->store->offsetGet($offset);
     }
 
-    public function offsetSet(mixed $offset, mixed $value)
+    public function offsetSet(mixed $offset, mixed $value): void
     {
         $this->store->offsetSet($offset, $value);
     }
 
-    public function offsetUnset(mixed $offset)
+    public function offsetUnset(mixed $offset): void
     {
         $this->store->offsetUnset($offset);
     }

Drivers/BaseCheckoutStore.php

@@ -188,7 +188,7 @@ public function dimension(): ?Dimension
         return null;
     }
 
-    public function offsetSet(mixed $offset, mixed $value)
+    public function offsetSet(mixed $offset, mixed $value): void
     {
         if ($this->isRegularAttribute($offset)) {
             $this->setAttribute($offset, $value);
@@ -197,7 +197,7 @@ public function offsetSet(mixed $offset, mixed $value)
         }
     }
 
-    public function offsetGet(mixed $offset)
+    public function offsetGet(mixed $offset): mixed
     {
         if ($this->isRegularAttribute($offset)) {
             return $this->getAttribute($offset);

Drivers/RequestStore.php

@@ -154,12 +154,12 @@ public function clear(): void
         $this->request->replace([]);
     }
 
-    public function offsetExists(mixed $offset)
+    public function offsetExists(mixed $offset): bool
     {
         return $this->request->has($offset);
     }
 
-    public function offsetUnset(mixed $offset)
+    public function offsetUnset(mixed $offset): void
     {
         $this->request->offsetUnset($offset);
     }

Drivers/SessionStore.php

@@ -113,7 +113,7 @@ public function getCustomAttributes(): array
         return $this->readRawDataFromStore(static::CUSTOM_ATTRIBUTES_KEY) ?? [];
     }
 
-    public function offsetExists(mixed $offset)
+    public function offsetExists(mixed $offset): bool
     {
         if ($this->isAnAliasAttribute($offset)) {
             $offset = $this->getTargetOfAlias($offset);
@@ -122,7 +122,7 @@ public function offsetExists(mixed $offset)
         return in_array($offset, array_merge($this->attributesPlain, $this->attributesViaGetterSetter));
     }
 
-    public function offsetUnset(mixed $offset)
+    public function offsetUnset(mixed $offset): void
     {
         $this->session->forget($offset);
     }