another bulk of composer updates

(cherry picked from commit 6685381fd8db507493c3d7c1793f8c05c681bbce)

24 files changed, 452 insertions, 483 deletions

diff --git a/vendor/sabre/xml/.gitignore b/vendor/sabre/xml/.gitignore
index accb586c7..51fc188bf 100644
--- a/vendor/sabre/xml/.gitignore
+++ b/vendor/sabre/xml/.gitignore
@@ -2,6 +2,7 @@ vendor
 composer.lock
 tests/cov
 .*.swp
+.php_cs.cache
 
 # Composer binaries
 bin/phpunit
diff --git a/vendor/sabre/xml/.php_cs.dist b/vendor/sabre/xml/.php_cs.dist
new file mode 100644
index 000000000..8d61ee259
--- /dev/null
+++ b/vendor/sabre/xml/.php_cs.dist
@@ -0,0 +1,12 @@
+<?php
+
+$config = PhpCsFixer\Config::create();
+$config->getFinder()
+    ->exclude('vendor')
+    ->in(__DIR__);
+$config->setRules([
+    '@PSR1' => true,
+    '@Symfony' =>true
+]);
+
+return $config;
\ No newline at end of file
diff --git a/vendor/sabre/xml/.travis.yml b/vendor/sabre/xml/.travis.yml
index 96396564e..49a0c9a22 100644
--- a/vendor/sabre/xml/.travis.yml
+++ b/vendor/sabre/xml/.travis.yml
@@ -1,26 +1,31 @@
 language: php
+sudo: required
+dist: xenial
 php:
-  - 5.5
-  - 5.6
   - 7.0
   - 7.1
+  - 7.2
+  - 7.3snapshot
+
+addons:
+  apt:
+    packages:
+    # required for php7.3
+    - libzip4
 
 matrix:
   fast_finish: true
 
-sudo: false
-
 cache:
   directories:
     - $HOME/.composer/cache
 
-before_install:
-  - phpenv config-rm xdebug.ini; true
-
 install:
   - composer install
 
 script:
-  - ./bin/phpunit --configuration tests/phpunit.xml.dist
-  - ./bin/sabre-cs-fixer fix . --dry-run --diff
+  - ./bin/phpunit --configuration tests/phpunit.xml.dist  --coverage-clover=coverage.xml
+
+after_success:
+- bash <(curl -s https://codecov.io/bash)
 
diff --git a/vendor/sabre/xml/CHANGELOG.md b/vendor/sabre/xml/CHANGELOG.md
index faeba20e5..1ad830124 100644
--- a/vendor/sabre/xml/CHANGELOG.md
+++ b/vendor/sabre/xml/CHANGELOG.md
@@ -1,11 +1,38 @@
 ChangeLog
 =========
 
-1.5.1 (2019-01-09)
+2.1.3 (2019-08-14)
+------------------
+
+* #166: Throw exception when empty inputs found
+
+2.1.2 (2019-01-09)
 ------------------
 
 * #161: Prevent infinite loop on empty xml elements
 
+2.1.1 (2018-10-09)
+------------------
+
+* #149: Properly detect xml parse errors in `parseCurrentElement()` edge-cases
+
+
+2.1.0 (2018-02-08)
+------------------
+
+* #112: Added a `mixedContent` deserializer function, which might be useful
+  if you're parsing HTML-like documents with elements that contain both text
+  and other elements as siblings. (@staabm).
+
+
+2.0.0 (2016-11-15)
+------------------
+
+* Now requires PHP 7.
+* Uses typehints everywhere.
+* Fixed some minor strict typing-related issues.
+* Removed workaround for PHP bug [64230](https://bugs.php.net/bug.php?id=64230).
+
 
 1.5.0 (2016-10-09)
 ------------------
diff --git a/vendor/sabre/xml/README.md b/vendor/sabre/xml/README.md
index e6fc4db5f..55af24fc6 100644
--- a/vendor/sabre/xml/README.md
+++ b/vendor/sabre/xml/README.md
@@ -1,7 +1,7 @@
 sabre/xml
 =========
 
-[![Build Status](https://secure.travis-ci.org/fruux/sabre-xml.svg?branch=master)](http://travis-ci.org/fruux/sabre-xml)
+[![Build Status](https://secure.travis-ci.org/sabre-io/xml.svg?branch=master)](http://travis-ci.org/sabre-io/xml)
 
 The sabre/xml library is a specialized XML reader and writer.
 
diff --git a/vendor/sabre/xml/composer.json b/vendor/sabre/xml/composer.json
index 1b5760393..c782dbc5e 100644
--- a/vendor/sabre/xml/composer.json
+++ b/vendor/sabre/xml/composer.json
@@ -5,7 +5,7 @@
     "homepage" : "https://sabre.io/xml/",
     "license" : "BSD-3-Clause",
     "require" : {
-        "php" : ">=5.5.5",
+        "php" : ">=7.0",
         "ext-xmlwriter" : "*",
         "ext-xmlreader" : "*",
         "ext-dom" : "*",
@@ -44,8 +44,7 @@
         }
     },
     "require-dev": {
-        "sabre/cs": "~1.0.0",
-        "phpunit/phpunit" : "~4.8|~5.7"
+        "phpunit/phpunit" : "^6"
     },
     "config" : {
         "bin-dir" : "bin/"
diff --git a/vendor/sabre/xml/lib/ContextStackTrait.php b/vendor/sabre/xml/lib/ContextStackTrait.php
index ee3a3baca..bc770ffad 100644
--- a/vendor/sabre/xml/lib/ContextStackTrait.php
+++ b/vendor/sabre/xml/lib/ContextStackTrait.php
@@ -1,9 +1,11 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Sabre\Xml;
 
 /**
- * Context Stack
+ * Context Stack.
  *
  * The Context maintains information about a document during either reading or
  * writing.
@@ -19,8 +21,8 @@ namespace Sabre\Xml;
  * @author Evert Pot (http://evertpot.com/)
  * @license http://sabre.io/license/ Modified BSD License
  */
-trait ContextStackTrait {
-
+trait ContextStackTrait
+{
     /**
      * This is the element map. It contains a list of XML elements (in clark
      * notation) as keys and PHP class names as values.
@@ -90,34 +92,27 @@ trait ContextStackTrait {
      * This allows you to safely modify the elementMap, contextUri or
      * namespaceMap. After you're done, you can restore the old data again
      * with popContext.
-     *
-     * @return null
      */
-    function pushContext() {
-
+    public function pushContext()
+    {
         $this->contextStack[] = [
             $this->elementMap,
             $this->contextUri,
             $this->namespaceMap,
-            $this->classMap
+            $this->classMap,
         ];
-
     }
 
     /**
      * Restore the previous "context".
-     *
-     * @return null
      */
-    function popContext() {
-
+    public function popContext()
+    {
         list(
             $this->elementMap,
             $this->contextUri,
             $this->namespaceMap,
             $this->classMap
         ) = array_pop($this->contextStack);
-
     }
-
 }
diff --git a/vendor/sabre/xml/lib/Deserializer/functions.php b/vendor/sabre/xml/lib/Deserializer/functions.php
index 07038d99a..0eff4b7e0 100644
--- a/vendor/sabre/xml/lib/Deserializer/functions.php
+++ b/vendor/sabre/xml/lib/Deserializer/functions.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Sabre\Xml\Deserializer;
 
 use Sabre\Xml\Reader;
@@ -52,17 +54,13 @@ use Sabre\Xml\Reader;
  *
  * Attributes will be removed from the top-level elements. If elements with
  * the same name appear twice in the list, only the last one will be kept.
- *
- *
- * @param Reader $reader
- * @param string $namespace
- * @return array
  */
-function keyValue(Reader $reader, $namespace = null) {
-
+function keyValue(Reader $reader, string $namespace = null): array
+{
     // If there's no children, we don't do anything.
     if ($reader->isEmptyElement) {
         $reader->next();
+
         return [];
     }
 
@@ -81,9 +79,8 @@ function keyValue(Reader $reader, $namespace = null) {
     $values = [];
 
     do {
-
-        if ($reader->nodeType === Reader::ELEMENT) {
-            if ($namespace !== null && $reader->namespaceURI === $namespace) {
+        if (Reader::ELEMENT === $reader->nodeType) {
+            if (null !== $namespace && $reader->namespaceURI === $namespace) {
                 $values[$reader->localName] = $reader->parseCurrentElement()['value'];
             } else {
                 $clark = $reader->getClark();
@@ -94,12 +91,11 @@ function keyValue(Reader $reader, $namespace = null) {
                 break;
             }
         }
-    } while ($reader->nodeType !== Reader::END_ELEMENT);
+    } while (Reader::END_ELEMENT !== $reader->nodeType);
 
     $reader->read();
 
     return $values;
-
 }
 
 /**
@@ -146,15 +142,14 @@ function keyValue(Reader $reader, $namespace = null) {
  *   "elem5",
  * ];
  *
- * @param Reader $reader
- * @param string $namespace
  * @return string[]
  */
-function enum(Reader $reader, $namespace = null) {
-
+function enum(Reader $reader, string $namespace = null): array
+{
     // If there's no children, we don't do anything.
     if ($reader->isEmptyElement) {
         $reader->next();
+
         return [];
     }
     if (!$reader->read()) {
@@ -172,8 +167,7 @@ function enum(Reader $reader, $namespace = null) {
 
     $values = [];
     do {
-
-        if ($reader->nodeType !== Reader::ELEMENT) {
+        if (Reader::ELEMENT !== $reader->nodeType) {
             continue;
         }
         if (!is_null($namespace) && $namespace === $reader->namespaceURI) {
@@ -181,12 +175,11 @@ function enum(Reader $reader, $namespace = null) {
         } else {
             $values[] = $reader->getClark();
         }
-
     } while ($reader->depth >= $currentDepth && $reader->next());
 
     $reader->next();
-    return $values;
 
+    return $values;
 }
 
 /**
@@ -196,16 +189,14 @@ function enum(Reader $reader, $namespace = null) {
  * This is primarily used by the mapValueObject function from the Service
  * class, but it can also easily be used for more specific situations.
  *
- * @param Reader $reader
- * @param string $className
- * @param string $namespace
  * @return object
  */
-function valueObject(Reader $reader, $className, $namespace) {
-
+function valueObject(Reader $reader, string $className, string $namespace)
+{
     $valueObject = new $className();
     if ($reader->isEmptyElement) {
         $reader->next();
+
         return $valueObject;
     }
 
@@ -213,9 +204,7 @@ function valueObject(Reader $reader, $className, $namespace) {
 
     $reader->read();
     do {
-
-        if ($reader->nodeType === Reader::ELEMENT && $reader->namespaceURI == $namespace) {
-
+        if (Reader::ELEMENT === $reader->nodeType && $reader->namespaceURI == $namespace) {
             if (property_exists($valueObject, $reader->localName)) {
                 if (is_array($defaultProperties[$reader->localName])) {
                     $valueObject->{$reader->localName}[] = $reader->parseCurrentElement()['value'];
@@ -231,16 +220,16 @@ function valueObject(Reader $reader, $className, $namespace) {
                 break;
             }
         }
-    } while ($reader->nodeType !== Reader::END_ELEMENT);
+    } while (Reader::END_ELEMENT !== $reader->nodeType);
 
     $reader->read();
-    return $valueObject;
 
+    return $valueObject;
 }
 
 /**
  * This deserializer helps you deserialize xml structures that look like
- * this:
+ * this:.
  *
  * <collection>
  *    <item>...</item>
@@ -248,7 +237,7 @@ function valueObject(Reader $reader, $className, $namespace) {
  *    <item>...</item>
  * </collection>
  *
- * Many XML documents use  patterns like that, and this deserializer
+ * Many XML documents use patterns like that, and this deserializer
  * allow you to get all the 'items' as an array.
  *
  * In that previous example, you would register the deserializer as such:
@@ -259,25 +248,71 @@ function valueObject(Reader $reader, $className, $namespace) {
  *
  * The repeatingElements deserializer simply returns everything as an array.
  *
- * @param Reader $reader
- * @param string $childElementName Element name in clark-notation
- * @return array
+ * $childElementName must either be a a clark-notation element name, or if no
+ * namespace is used, the bare element name.
  */
-function repeatingElements(Reader $reader, $childElementName) {
-
-    if ($childElementName[0] !== '{') {
-        $childElementName = '{}' . $childElementName;
+function repeatingElements(Reader $reader, string $childElementName): array
+{
+    if ('{' !== $childElementName[0]) {
+        $childElementName = '{}'.$childElementName;
     }
     $result = [];
 
     foreach ($reader->parseGetElements() as $element) {
-
         if ($element['name'] === $childElementName) {
             $result[] = $element['value'];
         }
-
     }
 
     return $result;
+}
+
+/**
+ * This deserializer helps you to deserialize structures which contain mixed content like this:.
+ *
+ * <p>some text <extref>and a inline tag</extref>and even more text</p>
+ *
+ * The above example will return
+ *
+ * [
+ *     'some text',
+ *     [
+ *         'name'       => '{}extref',
+ *         'value'      => 'and a inline tag',
+ *         'attributes' => []
+ *     ],
+ *     'and even more text'
+ * ]
+ *
+ * In strict XML documents you wont find this kind of markup but in html this is a quite common pattern.
+ */
+function mixedContent(Reader $reader): array
+{
+    // If there's no children, we don't do anything.
+    if ($reader->isEmptyElement) {
+        $reader->next();
+
+        return [];
+    }
+
+    $previousDepth = $reader->depth;
+
+    $content = [];
+    $reader->read();
+    while (true) {
+        if (Reader::ELEMENT == $reader->nodeType) {
+            $content[] = $reader->parseCurrentElement();
+        } elseif ($reader->depth >= $previousDepth && in_array($reader->nodeType, [Reader::TEXT, Reader::CDATA, Reader::WHITESPACE])) {
+            $content[] = $reader->value;
+            $reader->read();
+        } elseif (Reader::END_ELEMENT == $reader->nodeType) {
+            // Ensuring we are moving the cursor after the end element.
+            $reader->read();
+            break;
+        } else {
+            $reader->read();
+        }
+    }
 
+    return $content;
 }
diff --git a/vendor/sabre/xml/lib/Element.php b/vendor/sabre/xml/lib/Element.php
index dd89c5888..559eb54ea 100644
--- a/vendor/sabre/xml/lib/Element.php
+++ b/vendor/sabre/xml/lib/Element.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Sabre\Xml;
 
 /**
@@ -15,6 +17,6 @@ namespace Sabre\Xml;
  * @author Evert Pot (http://evertpot.com/)
  * @license http://sabre.io/license/ Modified BSD License
  */
-interface Element extends XmlSerializable, XmlDeserializable {
-
+interface Element extends XmlSerializable, XmlDeserializable
+{
 }
diff --git a/vendor/sabre/xml/lib/Element/Base.php b/vendor/sabre/xml/lib/Element/Base.php
index f59ba49a0..a1ce7ea5a 100644
--- a/vendor/sabre/xml/lib/Element/Base.php
+++ b/vendor/sabre/xml/lib/Element/Base.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Sabre\Xml\Element;
 
 use Sabre\Xml;
@@ -15,8 +17,8 @@ use Sabre\Xml;
  * @author Evert Pot (http://evertpot.com/)
  * @license http://sabre.io/license/ Modified BSD License
  */
-class Base implements Xml\Element {
-
+class Base implements Xml\Element
+{
     /**
      * PHP value to serialize.
      *
@@ -25,14 +27,11 @@ class Base implements Xml\Element {
     protected $value;
 
     /**
-     * Constructor
-     *
-     * @param mixed $value
+     * Constructor.
      */
-    function __construct($value = null) {
-
+    public function __construct($value = null)
+    {
         $this->value = $value;
-
     }
 
     /**
@@ -50,14 +49,10 @@ class Base implements Xml\Element {
      * This allows serializers to be re-used for different element names.
      *
      * If you are opening new elements, you must also close them again.
-     *
-     * @param Writer $writer
-     * @return void
      */
-    function xmlSerialize(Xml\Writer $writer) {
-
+    public function xmlSerialize(Xml\Writer $writer)
+    {
         $writer->write($this->value);
-
     }
 
     /**
@@ -78,14 +73,12 @@ class Base implements Xml\Element {
      * $reader->parseInnerTree() will parse the entire sub-tree, and advance to
      * the next element.
      *
-     * @param Xml\Reader $reader
      * @return mixed
      */
-    static function xmlDeserialize(Xml\Reader $reader) {
-
+    public static function xmlDeserialize(Xml\Reader $reader)
+    {
         $subTree = $reader->parseInnerTree();
-        return $subTree;
 
+        return $subTree;
     }
-
 }
diff --git a/vendor/sabre/xml/lib/Element/Cdata.php b/vendor/sabre/xml/lib/Element/Cdata.php
index 5f42c4c6e..61d3213ff 100644
--- a/vendor/sabre/xml/lib/Element/Cdata.php
+++ b/vendor/sabre/xml/lib/Element/Cdata.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Sabre\Xml\Element;
 
 use Sabre\Xml;
@@ -27,11 +29,9 @@ class Cdata implements Xml\XmlSerializable
     protected $value;
 
     /**
-     * Constructor
-     *
-     * @param string $value
+     * Constructor.
      */
-    function __construct($value)
+    public function __construct(string $value)
     {
         $this->value = $value;
     }
@@ -51,14 +51,9 @@ class Cdata implements Xml\XmlSerializable
      * This allows serializers to be re-used for different element names.
      *
      * If you are opening new elements, you must also close them again.
-     *
-     * @param Writer $writer
-     * @return void
      */
-    function xmlSerialize(Xml\Writer $writer) {
-
+    public function xmlSerialize(Xml\Writer $writer)
+    {
         $writer->writeCData($this->value);
-
     }
-
 }
diff --git a/vendor/sabre/xml/lib/Element/Elements.php b/vendor/sabre/xml/lib/Element/Elements.php
index 9eefd1bf8..e51179833 100644
--- a/vendor/sabre/xml/lib/Element/Elements.php
+++ b/vendor/sabre/xml/lib/Element/Elements.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Sabre\Xml\Element;
 
 use Sabre\Xml;
@@ -8,7 +10,7 @@ use Sabre\Xml\Serializer;
 
 /**
  * 'Elements' is a simple list of elements, without values or attributes.
- * For example, Elements will parse:
+ * For example, Elements will parse:.
  *
  * <?xml version="1.0"?>
  * <s:root xmlns:s="http://sabredav.org/ns">
@@ -33,24 +35,21 @@ use Sabre\Xml\Serializer;
  * @author Evert Pot (http://evertpot.com/)
  * @license http://sabre.io/license/ Modified BSD License
  */
-class Elements implements Xml\Element {
-
+class Elements implements Xml\Element
+{
     /**
-     * Value to serialize
+     * Value to serialize.
      *
      * @var array
      */
     protected $value;
 
     /**
-     * Constructor
-     *
-     * @param array $value
+     * Constructor.
      */
-    function __construct(array $value = []) {
-
+    public function __construct(array $value = [])
+    {
         $this->value = $value;
-
     }
 
     /**
@@ -68,14 +67,10 @@ class Elements implements Xml\Element {
      * This allows serializers to be re-used for different element names.
      *
      * If you are opening new elements, you must also close them again.
-     *
-     * @param Writer $writer
-     * @return void
      */
-    function xmlSerialize(Xml\Writer $writer) {
-
+    public function xmlSerialize(Xml\Writer $writer)
+    {
         Serializer\enum($writer, $this->value);
-
     }
 
     /**
@@ -96,13 +91,10 @@ class Elements implements Xml\Element {
      * $reader->parseSubTree() will parse the entire sub-tree, and advance to
      * the next element.
      *
-     * @param Xml\Reader $reader
      * @return mixed
      */
-    static function xmlDeserialize(Xml\Reader $reader) {
-
+    public static function xmlDeserialize(Xml\Reader $reader)
+    {
         return Deserializer\enum($reader);
-
     }
-
 }
diff --git a/vendor/sabre/xml/lib/Element/KeyValue.php b/vendor/sabre/xml/lib/Element/KeyValue.php
index 7ce53bf4c..dacee000a 100644
--- a/vendor/sabre/xml/lib/Element/KeyValue.php
+++ b/vendor/sabre/xml/lib/Element/KeyValue.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Sabre\Xml\Element;
 
 use Sabre\Xml;
@@ -33,24 +35,21 @@ use Sabre\Xml\Deserializer;
  * @author Evert Pot (http://evertpot.com/)
  * @license http://sabre.io/license/ Modified BSD License
  */
-class KeyValue implements Xml\Element {
-
+class KeyValue implements Xml\Element
+{
     /**
-     * Value to serialize
+     * Value to serialize.
      *
      * @var array
      */
     protected $value;
 
     /**
-     * Constructor
-     *
-     * @param array $value
+     * Constructor.
      */
-    function __construct(array $value = []) {
-
+    public function __construct(array $value = [])
+    {
         $this->value = $value;
-
     }
 
     /**
@@ -68,14 +67,10 @@ class KeyValue implements Xml\Element {
      * This allows serializers to be re-used for different element names.
      *
      * If you are opening new elements, you must also close them again.
-     *
-     * @param Writer $writer
-     * @return void
      */
-    function xmlSerialize(Xml\Writer $writer) {
-
+    public function xmlSerialize(Xml\Writer $writer)
+    {
         $writer->write($this->value);
-
     }
 
     /**
@@ -96,13 +91,10 @@ class KeyValue implements Xml\Element {
      * $reader->parseInnerTree() will parse the entire sub-tree, and advance to
      * the next element.
      *
-     * @param Xml\Reader $reader
      * @return mixed
      */
-    static function xmlDeserialize(Xml\Reader $reader) {
-
+    public static function xmlDeserialize(Xml\Reader $reader)
+    {
         return Deserializer\keyValue($reader);
-
     }
-
 }
diff --git a/vendor/sabre/xml/lib/Element/Uri.php b/vendor/sabre/xml/lib/Element/Uri.php
index 8f45c0027..898a26457 100644
--- a/vendor/sabre/xml/lib/Element/Uri.php
+++ b/vendor/sabre/xml/lib/Element/Uri.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Sabre\Xml\Element;
 
 use Sabre\Xml;
@@ -20,8 +22,8 @@ use Sabre\Xml;
  * @author Evert Pot (http://evertpot.com/)
  * @license http://sabre.io/license/ Modified BSD License
  */
-class Uri implements Xml\Element {
-
+class Uri implements Xml\Element
+{
     /**
      * Uri element value.
      *
@@ -30,11 +32,11 @@ class Uri implements Xml\Element {
     protected $value;
 
     /**
-     * Constructor
+     * Constructor.
      *
      * @param string $value
      */
-    function __construct($value)
+    public function __construct($value)
     {
         $this->value = $value;
     }
@@ -54,19 +56,15 @@ class Uri implements Xml\Element {
      * This allows serializers to be re-used for different element names.
      *
      * If you are opening new elements, you must also close them again.
-     *
-     * @param Writer $writer
-     * @return void
      */
-    function xmlSerialize(Xml\Writer $writer) {
-
+    public function xmlSerialize(Xml\Writer $writer)
+    {
         $writer->text(
             \Sabre\Uri\resolve(
                 $writer->contextUri,
                 $this->value
             )
         );
-
     }
 
     /**
@@ -87,18 +85,15 @@ class Uri implements Xml\Element {
      * $reader->parseSubTree() will parse the entire sub-tree, and advance to
      * the next element.
      *
-     * @param Xml\Reader $reader
      * @return mixed
      */
-    static function xmlDeserialize(Xml\Reader $reader) {
-
+    public static function xmlDeserialize(Xml\Reader $reader)
+    {
         return new self(
             \Sabre\Uri\resolve(
                 $reader->contextUri,
                 $reader->readText()
             )
         );
-
     }
-
 }
diff --git a/vendor/sabre/xml/lib/Element/XmlFragment.php b/vendor/sabre/xml/lib/Element/XmlFragment.php
index 642241ca4..413e0f106 100644
--- a/vendor/sabre/xml/lib/Element/XmlFragment.php
+++ b/vendor/sabre/xml/lib/Element/XmlFragment.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Sabre\Xml\Element;
 
 use Sabre\Xml\Element;
@@ -20,20 +22,29 @@ use Sabre\Xml\Writer;
  * 3. It will have all the relevant xmlns attributes.
  * 4. It may not have a root element.
  */
-class XmlFragment implements Element {
-
+class XmlFragment implements Element
+{
+    /**
+     * The inner XML value.
+     *
+     * @var string
+     */
     protected $xml;
 
-    function __construct($xml) {
-
+    /**
+     * Constructor.
+     */
+    public function __construct(string $xml)
+    {
         $this->xml = $xml;
-
     }
 
-    function getXml() {
-
+    /**
+     * Returns the inner XML document.
+     */
+    public function getXml(): string
+    {
         return $this->xml;
-
     }
 
     /**
@@ -51,12 +62,9 @@ class XmlFragment implements Element {
      * This allows serializers to be re-used for different element names.
      *
      * If you are opening new elements, you must also close them again.
-     *
-     * @param Writer $writer
-     * @return void
      */
-    function xmlSerialize(Writer $writer) {
-
+    public function xmlSerialize(Writer $writer)
+    {
         $reader = new Reader();
 
         // Wrapping the xml in a container, so root-less values can still be
@@ -69,28 +77,26 @@ XML;
         $reader->xml($xml);
 
         while ($reader->read()) {
-
             if ($reader->depth < 1) {
                 // Skipping the root node.
                 continue;
             }
 
             switch ($reader->nodeType) {
-
-                case Reader::ELEMENT :
+                case Reader::ELEMENT:
                     $writer->startElement(
                         $reader->getClark()
                     );
                     $empty = $reader->isEmptyElement;
                     while ($reader->moveToNextAttribute()) {
                         switch ($reader->namespaceURI) {
-                            case '' :
+                            case '':
                                 $writer->writeAttribute($reader->localName, $reader->value);
                                 break;
-                            case 'http://www.w3.org/2000/xmlns/' :
+                            case 'http://www.w3.org/2000/xmlns/':
                                 // Skip namespace declarations
                                 break;
-                            default :
+                            default:
                                 $writer->writeAttribute($reader->getClark(), $reader->value);
                                 break;
                         }
@@ -99,20 +105,17 @@ XML;
                         $writer->endElement();
                     }
                     break;
-                case Reader::CDATA :
-                case Reader::TEXT :
+                case Reader::CDATA:
+                case Reader::TEXT:
                     $writer->text(
                         $reader->value
                     );
                     break;
-                case Reader::END_ELEMENT :
+                case Reader::END_ELEMENT:
                     $writer->endElement();
                     break;
-
             }
-
         }
-
     }
 
     /**
@@ -133,15 +136,13 @@ XML;
      * $reader->parseInnerTree() will parse the entire sub-tree, and advance to
      * the next element.
      *
-     * @param Reader $reader
      * @return mixed
      */
-    static function xmlDeserialize(Reader $reader) {
-
+    public static function xmlDeserialize(Reader $reader)
+    {
         $result = new self($reader->readInnerXml());
         $reader->next();
-        return $result;
 
+        return $result;
     }
-
 }
diff --git a/vendor/sabre/xml/lib/LibXMLException.php b/vendor/sabre/xml/lib/LibXMLException.php
index f0190eb51..4701c304a 100644
--- a/vendor/sabre/xml/lib/LibXMLException.php
+++ b/vendor/sabre/xml/lib/LibXMLException.php
@@ -1,9 +1,11 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Sabre\Xml;
 
-use
-    LibXMLError;
+use LibXMLError;
+use Throwable;
 
 /**
  * This exception is thrown when the Readers runs into a parsing error.
@@ -14,12 +16,12 @@ use
  * @author Evert Pot (http://evertpot.com/)
  * @license http://sabre.io/license/ Modified BSD License
  */
-class LibXMLException extends ParseException {
-
+class LibXMLException extends ParseException
+{
     /**
      * The error list.
      *
-     * @var LibXMLError[]
+     * @var []LibXMLError
      */
     protected $errors;
 
@@ -28,26 +30,21 @@ class LibXMLException extends ParseException {
      *
      * You should pass a list of LibXMLError objects in its constructor.
      *
-     * @param LibXMLError[] $errors
-     * @param int $code
-     * @param Exception $previousException
+     * @param []LibXMLError $errors
+     * @param int           $code
+     * @param Throwable     $previousException
      */
-    function __construct(array $errors, $code = null, Exception $previousException = null) {
-
+    public function __construct(array $errors, int $code = 0, Throwable $previousException = null)
+    {
         $this->errors = $errors;
-        parent::__construct($errors[0]->message . ' on line ' . $errors[0]->line . ', column ' . $errors[0]->column, $code, $previousException);
-
+        parent::__construct($errors[0]->message.' on line '.$errors[0]->line.', column '.$errors[0]->column, $code, $previousException);
     }
 
     /**
-     * Returns the LibXML errors
-     *
-     * @return void
+     * Returns the LibXML errors.
      */
-    function getErrors() {
-
+    public function getErrors(): array
+    {
         return $this->errors;
-
     }
-
 }
diff --git a/vendor/sabre/xml/lib/ParseException.php b/vendor/sabre/xml/lib/ParseException.php
index 3a6883b2f..e237b8732 100644
--- a/vendor/sabre/xml/lib/ParseException.php
+++ b/vendor/sabre/xml/lib/ParseException.php
@@ -1,9 +1,10 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Sabre\Xml;
 
-use
-    Exception;
+use Exception;
 
 /**
  * This is a base exception for any exception related to parsing xml files.
@@ -12,6 +13,6 @@ use
  * @author Evert Pot (http://evertpot.com/)
  * @license http://sabre.io/license/ Modified BSD License
  */
-class ParseException extends Exception {
-
+class ParseException extends Exception
+{
 }
diff --git a/vendor/sabre/xml/lib/Reader.php b/vendor/sabre/xml/lib/Reader.php
index 92e5dba96..37e0c86dd 100644
--- a/vendor/sabre/xml/lib/Reader.php
+++ b/vendor/sabre/xml/lib/Reader.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Sabre\Xml;
 
 use XMLReader;
@@ -17,8 +19,8 @@ use XMLReader;
  * @author Evert Pot (http://evertpot.com/)
  * @license http://sabre.io/license/ Modified BSD License
  */
-class Reader extends XMLReader {
-
+class Reader extends XMLReader
+{
     use ContextStackTrait;
 
     /**
@@ -31,14 +33,13 @@ class Reader extends XMLReader {
      *
      * @return string|null
      */
-    function getClark() {
-
-        if (! $this->localName) {
+    public function getClark()
+    {
+        if (!$this->localName) {
             return null;
         }
 
-        return '{' . $this->namespaceURI . '}' . $this->localName;
-
+        return '{'.$this->namespaceURI.'}'.$this->localName;
     }
 
     /**
@@ -51,31 +52,30 @@ class Reader extends XMLReader {
      *
      * This function will also disable the standard libxml error handler (which
      * usually just results in PHP errors), and throw exceptions instead.
-     *
-     * @return array
      */
-    function parse() {
-
+    public function parse(): array
+    {
         $previousEntityState = libxml_disable_entity_loader(true);
         $previousSetting = libxml_use_internal_errors(true);
 
         try {
-
-            // Really sorry about the silence operator, seems like I have no
-            // choice. See:
-            //
-            // https://bugs.php.net/bug.php?id=64230
-            while ($this->nodeType !== self::ELEMENT && @$this->read()) {
-                // noop
+            while (self::ELEMENT !== $this->nodeType) {
+                if (!$this->read()) {
+                    $errors = libxml_get_errors();
+                    libxml_clear_errors();
+                    if ($errors) {
+                        throw new LibXMLException($errors);
+                    }
+                }
             }
             $result = $this->parseCurrentElement();
 
+            // last line of defense in case errors did occur above
             $errors = libxml_get_errors();
             libxml_clear_errors();
             if ($errors) {
                 throw new LibXMLException($errors);
             }
-
         } finally {
             libxml_use_internal_errors($previousSetting);
             libxml_disable_entity_loader($previousEntityState);
@@ -84,8 +84,6 @@ class Reader extends XMLReader {
         return $result;
     }
 
-
-
     /**
      * parseGetElements parses everything in the current sub-tree,
      * and returns a an array of elements.
@@ -98,18 +96,15 @@ class Reader extends XMLReader {
      *
      * If the $elementMap argument is specified, the existing elementMap will
      * be overridden while parsing the tree, and restored after this process.
-     *
-     * @param array $elementMap
-     * @return array
      */
-    function parseGetElements(array $elementMap = null) {
-
+    public function parseGetElements(array $elementMap = null): array
+    {
         $result = $this->parseInnerTree($elementMap);
         if (!is_array($result)) {
             return [];
         }
-        return $result;
 
+        return $result;
     }
 
     /**
@@ -123,17 +118,17 @@ class Reader extends XMLReader {
      * If the $elementMap argument is specified, the existing elementMap will
      * be overridden while parsing the tree, and restored after this process.
      *
-     * @param array $elementMap
      * @return array|string
      */
-    function parseInnerTree(array $elementMap = null) {
-
+    public function parseInnerTree(array $elementMap = null)
+    {
         $text = null;
         $elements = [];
 
-        if ($this->nodeType === self::ELEMENT && $this->isEmptyElement) {
+        if (self::ELEMENT === $this->nodeType && $this->isEmptyElement) {
             // Easy!
             $this->next();
+
             return null;
         }
 
@@ -143,12 +138,7 @@ class Reader extends XMLReader {
         }
 
         try {
-
-            // Really sorry about the silence operator, seems like I have no
-            // choice. See:
-            //
-            // https://bugs.php.net/bug.php?id=64230
-            if (!@$this->read()) {
+            if (!$this->read()) {
                 $errors = libxml_get_errors();
                 libxml_clear_errors();
                 if ($errors) {
@@ -158,9 +148,7 @@ class Reader extends XMLReader {
             }
 
             while (true) {
-
                 if (!$this->isValid()) {
-
                     $errors = libxml_get_errors();
 
                     if ($errors) {
@@ -170,46 +158,40 @@ class Reader extends XMLReader {
                 }
 
                 switch ($this->nodeType) {
-                    case self::ELEMENT :
+                    case self::ELEMENT:
                         $elements[] = $this->parseCurrentElement();
                         break;
-                    case self::TEXT :
-                    case self::CDATA :
+                    case self::TEXT:
+                    case self::CDATA:
                         $text .= $this->value;
                         $this->read();
                         break;
-                    case self::END_ELEMENT :
+                    case self::END_ELEMENT:
                         // Ensuring we are moving the cursor after the end element.
                         $this->read();
                         break 2;
-                    case self::NONE :
+                    case self::NONE:
                         throw new ParseException('We hit the end of the document prematurely. This likely means that some parser "eats" too many elements. Do not attempt to continue parsing.');
-                    default :
+                    default:
                         // Advance to the next element
                         $this->read();
                         break;
                 }
-
             }
-
         } finally {
-
             if (!is_null($elementMap)) {
                 $this->popContext();
             }
-
         }
-        return ($elements ? $elements : $text);
 
+        return $elements ? $elements : $text;
     }
 
     /**
      * Reads all text below the current element, and returns this as a string.
-     *
-     * @return string
      */
-    function readText() {
-
+    public function readText(): string
+    {
         $result = '';
         $previousDepth = $this->depth;
 
@@ -218,8 +200,8 @@ class Reader extends XMLReader {
                 $result .= $this->value;
             }
         }
-        return $result;
 
+        return $result;
     }
 
     /**
@@ -229,11 +211,9 @@ class Reader extends XMLReader {
      *   * name - A clark-notation XML element name.
      *   * value - The parsed value.
      *   * attributes - A key-value list of attributes.
-     *
-     * @return array
      */
-    function parseCurrentElement() {
-
+    public function parseCurrentElement(): array
+    {
         $name = $this->getClark();
 
         $attributes = [];
@@ -248,13 +228,12 @@ class Reader extends XMLReader {
         );
 
         return [
-            'name'       => $name,
-            'value'      => $value,
+            'name' => $name,
+            'value' => $value,
             'attributes' => $attributes,
         ];
     }
 
-
     /**
      * Grabs all the attributes from the current element, and returns them as a
      * key-value array.
@@ -262,24 +241,20 @@ class Reader extends XMLReader {
      * If the attributes are part of the same namespace, they will simply be
      * short keys. If they are defined on a different namespace, the attribute
      * name will be retured in clark-notation.
-     *
-     * @return array
      */
-    function parseAttributes() {
-
+    public function parseAttributes(): array
+    {
         $attributes = [];
 
         while ($this->moveToNextAttribute()) {
             if ($this->namespaceURI) {
-
                 // Ignoring 'xmlns', it doesn't make any sense.
-                if ($this->namespaceURI === 'http://www.w3.org/2000/xmlns/') {
+                if ('http://www.w3.org/2000/xmlns/' === $this->namespaceURI) {
                     continue;
                 }
 
                 $name = $this->getClark();
                 $attributes[$name] = $this->value;
-
             } else {
                 $attributes[$this->localName] = $this->value;
             }
@@ -287,21 +262,16 @@ class Reader extends XMLReader {
         $this->moveToElement();
 
         return $attributes;
-
     }
 
     /**
      * Returns the function that should be used to parse the element identified
      * by it's clark-notation name.
-     *
-     * @param string $name
-     * @return callable
      */
-    function getDeserializerForElementName($name) {
-
-
+    public function getDeserializerForElementName(string $name): callable
+    {
         if (!array_key_exists($name, $this->elementMap)) {
-            if (substr($name, 0, 2) == '{}' && array_key_exists(substr($name, 2), $this->elementMap)) {
+            if ('{}' == substr($name, 0, 2) && array_key_exists(substr($name, 2), $this->elementMap)) {
                 $name = substr($name, 2);
             } else {
                 return ['Sabre\\Xml\\Element\\Base', 'xmlDeserialize'];
@@ -318,13 +288,11 @@ class Reader extends XMLReader {
         }
 
         $type = gettype($deserializer);
-        if ($type === 'string') {
-            $type .= ' (' . $deserializer . ')';
-        } elseif ($type === 'object') {
-            $type .= ' (' . get_class($deserializer) . ')';
+        if ('string' === $type) {
+            $type .= ' ('.$deserializer.')';
+        } elseif ('object' === $type) {
+            $type .= ' ('.get_class($deserializer).')';
         }
-        throw new \LogicException('Could not use this type as a deserializer: ' . $type . ' for element: ' . $name);
-
+        throw new \LogicException('Could not use this type as a deserializer: '.$type.' for element: '.$name);
     }
-
 }
diff --git a/vendor/sabre/xml/lib/Serializer/functions.php b/vendor/sabre/xml/lib/Serializer/functions.php
index 21448017d..3694d9791 100644
--- a/vendor/sabre/xml/lib/Serializer/functions.php
+++ b/vendor/sabre/xml/lib/Serializer/functions.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Sabre\Xml\Serializer;
 
 use InvalidArgumentException;
@@ -34,12 +36,10 @@ use Sabre\Xml\XmlSerializable;
  * <s:elem4>content</s:elem4>
  * <s:elem5 attr="val" />
  *
- * @param Writer $writer
  * @param string[] $values
- * @return void
  */
-function enum(Writer $writer, array $values) {
-
+function enum(Writer $writer, array $values)
+{
     foreach ($values as $value) {
         $writer->writeElement($value);
     }
@@ -54,29 +54,26 @@ function enum(Writer $writer, array $values) {
  * Values that are set to null or an empty array are not serialized. To
  * serialize empty properties, you must specify them as an empty string.
  *
- * @param Writer $writer
  * @param object $valueObject
- * @param string $namespace
  */
-function valueObject(Writer $writer, $valueObject, $namespace) {
+function valueObject(Writer $writer, $valueObject, string $namespace)
+{
     foreach (get_object_vars($valueObject) as $key => $val) {
         if (is_array($val)) {
             // If $val is an array, it has a special meaning. We need to
             // generate one child element for each item in $val
             foreach ($val as $child) {
-                $writer->writeElement('{' . $namespace . '}' . $key, $child);
+                $writer->writeElement('{'.$namespace.'}'.$key, $child);
             }
-
-        } elseif ($val !== null) {
-            $writer->writeElement('{' . $namespace . '}' . $key, $val);
+        } elseif (null !== $val) {
+            $writer->writeElement('{'.$namespace.'}'.$key, $val);
         }
     }
 }
 
-
 /**
  * This serializer helps you serialize xml structures that look like
- * this:
+ * this:.
  *
  * <collection>
  *    <item>...</item>
@@ -88,18 +85,12 @@ function valueObject(Writer $writer, $valueObject, $namespace) {
  * and this could be called like this:
  *
  * repeatingElements($writer, $items, '{}item');
- *
- * @param Writer $writer
- * @param array $items A list of items sabre/xml can serialize.
- * @param string $childElementName Element name in clark-notation
- * @return void
  */
-function repeatingElements(Writer $writer, array $items, $childElementName) {
-
+function repeatingElements(Writer $writer, array $items, string $childElementName)
+{
     foreach ($items as $item) {
         $writer->writeElement($childElementName, $item);
     }
-
 }
 
 /**
@@ -157,38 +148,25 @@ function repeatingElements(Writer $writer, array $items, $childElementName) {
  *
  * You can even mix the two array syntaxes.
  *
- * @param Writer $writer
  * @param string|int|float|bool|array|object
- * @return void
  */
-function standardSerializer(Writer $writer, $value) {
-
+function standardSerializer(Writer $writer, $value)
+{
     if (is_scalar($value)) {
-
         // String, integer, float, boolean
-        $writer->text($value);
-
+        $writer->text((string) $value);
     } elseif ($value instanceof XmlSerializable) {
-
         // XmlSerializable classes or Element classes.
         $value->xmlSerialize($writer);
-
     } elseif (is_object($value) && isset($writer->classMap[get_class($value)])) {
-
         // It's an object which class appears in the classmap.
         $writer->classMap[get_class($value)]($writer, $value);
-
     } elseif (is_callable($value)) {
-
         // A callback
         $value($writer);
-
     } elseif (is_null($value)) {
-
         // nothing!
-
     } elseif (is_array($value) && array_key_exists('name', $value)) {
-
         // if the array had a 'name' element, we assume that this array
         // describes a 'name' and optionally 'attributes' and 'value'.
 
@@ -200,19 +178,13 @@ function standardSerializer(Writer $writer, $value) {
         $writer->writeAttributes($attributes);
         $writer->write($value);
         $writer->endElement();
-
     } elseif (is_array($value)) {
-
         foreach ($value as $name => $item) {
-
             if (is_int($name)) {
-
                 // This item has a numeric index. We just loop through the
                 // array and throw it back in the writer.
                 standardSerializer($writer, $item);
-
             } elseif (is_string($name) && is_array($item) && isset($item['attributes'])) {
-
                 // The key is used for a name, but $item has 'attributes' and
                 // possibly 'value'
                 $writer->startElement($name);
@@ -221,29 +193,18 @@ function standardSerializer(Writer $writer, $value) {
                     $writer->write($item['value']);
                 }
                 $writer->endElement();
-
             } elseif (is_string($name)) {
-
                 // This was a plain key-value array.
                 $writer->startElement($name);
                 $writer->write($item);
                 $writer->endElement();
-
             } else {
-
-                throw new InvalidArgumentException('The writer does not know how to serialize arrays with keys of type: ' . gettype($name));
-
+                throw new InvalidArgumentException('The writer does not know how to serialize arrays with keys of type: '.gettype($name));
             }
         }
-
     } elseif (is_object($value)) {
-
-        throw new InvalidArgumentException('The writer cannot serialize objects of class: ' . get_class($value));
-
+        throw new InvalidArgumentException('The writer cannot serialize objects of class: '.get_class($value));
     } else {
-
-        throw new InvalidArgumentException('The writer cannot serialize values of type: ' . gettype($value));
-
+        throw new InvalidArgumentException('The writer cannot serialize values of type: '.gettype($value));
     }
-
 }
diff --git a/vendor/sabre/xml/lib/Service.php b/vendor/sabre/xml/lib/Service.php
index acea94ea9..882b2dc2c 100644
--- a/vendor/sabre/xml/lib/Service.php
+++ b/vendor/sabre/xml/lib/Service.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Sabre\Xml;
 
 /**
@@ -13,8 +15,8 @@ namespace Sabre\Xml;
  * @author Evert Pot (http://evertpot.com/)
  * @license http://sabre.io/license/ Modified BSD License
  */
-class Service {
-
+class Service
+{
     /**
      * This is the element map. It contains a list of XML elements (in clark
      * notation) as keys and PHP class names as values.
@@ -59,30 +61,26 @@ class Service {
     public $classMap = [];
 
     /**
-     * Returns a fresh XML Reader
-     *
-     * @return Reader
+     * Returns a fresh XML Reader.
      */
-    function getReader() {
-
+    public function getReader(): Reader
+    {
         $r = new Reader();
         $r->elementMap = $this->elementMap;
-        return $r;
 
+        return $r;
     }
 
     /**
-     * Returns a fresh xml writer
-     *
-     * @return Writer
+     * Returns a fresh xml writer.
      */
-    function getWriter() {
-
+    public function getWriter(): Writer
+    {
         $w = new Writer();
         $w->namespaceMap = $this->namespaceMap;
         $w->classMap = $this->classMap;
-        return $w;
 
+        return $w;
     }
 
     /**
@@ -99,17 +97,22 @@ class Service {
      * with the root element name of the document.
      *
      * @param string|resource $input
-     * @param string|null $contextUri
-     * @param string|null $rootElementName
+     *
      * @throws ParseException
+     *
      * @return array|object|string
      */
-    function parse($input, $contextUri = null, &$rootElementName = null) {
-
+    public function parse($input, string $contextUri = null, string &$rootElementName = null)
+    {
         if (is_resource($input)) {
             // Unfortunately the XMLReader doesn't support streams. When it
             // does, we can optimize this.
             $input = stream_get_contents($input);
+
+            // If input is an empty string, then its safe to throw exception
+            if ('' === $input) {
+                throw new ParseException('The input element to parse is empty. Do not attempt to parse');
+            }
         }
         $r = $this->getReader();
         $r->contextUri = $contextUri;
@@ -117,8 +120,8 @@ class Service {
 
         $result = $r->parse();
         $rootElementName = $result['name'];
-        return $result['value'];
 
+        return $result['value'];
     }
 
     /**
@@ -137,33 +140,42 @@ class Service {
      *
      * @param string|string[] $rootElementName
      * @param string|resource $input
-     * @param string|null $contextUri
+     * @param string|null     $contextUri
+     *
      * @throws ParseException
+     *
      * @return array|object|string
      */
-    function expect($rootElementName, $input, $contextUri = null) {
-
+    public function expect($rootElementName, $input, string $contextUri = null)
+    {
         if (is_resource($input)) {
             // Unfortunately the XMLReader doesn't support streams. When it
             // does, we can optimize this.
             $input = stream_get_contents($input);
+
+            // If input is empty string, then its safe to throw exception
+            if ('' === $input) {
+                throw new ParseException('The input element to parse is empty. Do not attempt to parse');
+            }
         }
         $r = $this->getReader();
         $r->contextUri = $contextUri;
         $r->xml($input);
 
-        $rootElementName = (array)$rootElementName;
+        $rootElementName = (array) $rootElementName;
 
         foreach ($rootElementName as &$rEl) {
-            if ($rEl[0] !== '{') $rEl = '{}' . $rEl;
+            if ('{' !== $rEl[0]) {
+                $rEl = '{}'.$rEl;
+            }
         }
 
         $result = $r->parse();
         if (!in_array($result['name'], $rootElementName, true)) {
-            throw new ParseException('Expected ' . implode(' or ', (array)$rootElementName) . ' but received ' . $result['name'] . ' as the root element');
+            throw new ParseException('Expected '.implode(' or ', (array) $rootElementName).' but received '.$result['name'].' as the root element');
         }
-        return $result['value'];
 
+        return $result['value'];
     }
 
     /**
@@ -180,20 +192,20 @@ class Service {
      * This allows an implementor to easily create URI's relative to the root
      * of the domain.
      *
-     * @param string $rootElementName
      * @param string|array|XmlSerializable $value
-     * @param string|null $contextUri
+     *
+     * @return string
      */
-    function write($rootElementName, $value, $contextUri = null) {
-
+    public function write(string $rootElementName, $value, string $contextUri = null)
+    {
         $w = $this->getWriter();
         $w->openMemory();
         $w->contextUri = $contextUri;
         $w->setIndent(true);
         $w->startDocument();
         $w->writeElement($rootElementName, $value);
-        return $w->outputMemory();
 
+        return $w->outputMemory();
     }
 
     /**
@@ -219,18 +231,15 @@ class Service {
      * These can easily be mapped by calling:
      *
      * $service->mapValueObject('{http://example.org}author', 'Author');
-     *
-     * @param string $elementName
-     * @param object $className
-     * @return void
      */
-    function mapValueObject($elementName, $className) {
+    public function mapValueObject(string $elementName, string $className)
+    {
         list($namespace) = self::parseClarkNotation($elementName);
 
-        $this->elementMap[$elementName] = function(Reader $reader) use ($className, $namespace) {
+        $this->elementMap[$elementName] = function (Reader $reader) use ($className, $namespace) {
             return \Sabre\Xml\Deserializer\valueObject($reader, $className, $namespace);
         };
-        $this->classMap[$className] = function(Writer $writer, $valueObject) use ($namespace) {
+        $this->classMap[$className] = function (Writer $writer, $valueObject) use ($namespace) {
             return \Sabre\Xml\Serializer\valueObject($writer, $valueObject, $namespace);
         };
         $this->valueObjectMap[$className] = $elementName;
@@ -246,20 +255,20 @@ class Service {
      * mapValueObject().
      *
      * @param object $object
-     * @param string $contextUri
-     * @return void
+     *
+     * @throws \InvalidArgumentException
      */
-    function writeValueObject($object, $contextUri = null) {
-
+    public function writeValueObject($object, string $contextUri = null)
+    {
         if (!isset($this->valueObjectMap[get_class($object)])) {
-            throw new \InvalidArgumentException('"' . get_class($object) . '" is not a registered value object class. Register your class with mapValueObject.');
+            throw new \InvalidArgumentException('"'.get_class($object).'" is not a registered value object class. Register your class with mapValueObject.');
         }
+
         return $this->write(
             $this->valueObjectMap[get_class($object)],
             $object,
             $contextUri
         );
-
     }
 
     /**
@@ -268,22 +277,20 @@ class Service {
      *
      * If the string was invalid, it will throw an InvalidArgumentException.
      *
-     * @param string $str
-     * @throws InvalidArgumentException
-     * @return array
+     * @throws \InvalidArgumentException
      */
-    static function parseClarkNotation($str) {
+    public static function parseClarkNotation(string $str): array
+    {
         static $cache = [];
 
         if (!isset($cache[$str])) {
-
             if (!preg_match('/^{([^}]*)}(.*)$/', $str, $matches)) {
-                throw new \InvalidArgumentException('\'' . $str . '\' is not a valid clark-notation formatted string');
+                throw new \InvalidArgumentException('\''.$str.'\' is not a valid clark-notation formatted string');
             }
 
             $cache[$str] = [
                 $matches[1],
-                $matches[2]
+                $matches[2],
             ];
         }
 
@@ -294,5 +301,4 @@ class Service {
      * A list of classes and which XML elements they map to.
      */
     protected $valueObjectMap = [];
-
 }
diff --git a/vendor/sabre/xml/lib/Version.php b/vendor/sabre/xml/lib/Version.php
index 7edb40d67..65706ec42 100644
--- a/vendor/sabre/xml/lib/Version.php
+++ b/vendor/sabre/xml/lib/Version.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Sabre\Xml;
 
 /**
@@ -9,11 +11,10 @@ namespace Sabre\Xml;
  * @author Evert Pot (http://evertpot.com/)
  * @license http://sabre.io/license/
  */
-class Version {
-
+class Version
+{
     /**
-     * Full version number
+     * Full version number.
      */
-    const VERSION = '1.5.0';
-
+    const VERSION = '2.1.1';
 }
diff --git a/vendor/sabre/xml/lib/Writer.php b/vendor/sabre/xml/lib/Writer.php
index 09d4cb321..f5957bbce 100644
--- a/vendor/sabre/xml/lib/Writer.php
+++ b/vendor/sabre/xml/lib/Writer.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Sabre\Xml;
 
 use XMLWriter;
@@ -28,8 +30,8 @@ use XMLWriter;
  * @author Evert Pot (http://evertpot.com/)
  * @license http://sabre.io/license/ Modified BSD License
  */
-class Writer extends XMLWriter {
-
+class Writer extends XMLWriter
+{
     use ContextStackTrait;
 
     /**
@@ -93,12 +95,10 @@ class Writer extends XMLWriter {
      * ]
      *
      * @param mixed $value
-     * @return void
      */
-    function write($value) {
-
+    public function write($value)
+    {
         Serializer\standardSerializer($this, $value);
-
     }
 
     /**
@@ -115,52 +115,48 @@ class Writer extends XMLWriter {
      *
      *     <entry xmlns="http://w3.org/2005/Atom">
      *
+     * Note: this function doesn't have the string typehint, because PHP's
+     * XMLWriter::startElement doesn't either.
+     *
      * @param string $name
-     * @return bool
      */
-    function startElement($name) {
-
-        if ($name[0] === '{') {
-
+    public function startElement($name): bool
+    {
+        if ('{' === $name[0]) {
             list($namespace, $localName) =
                 Service::parseClarkNotation($name);
 
             if (array_key_exists($namespace, $this->namespaceMap)) {
                 $result = $this->startElementNS(
-                    $this->namespaceMap[$namespace] === '' ? null : $this->namespaceMap[$namespace],
+                    '' === $this->namespaceMap[$namespace] ? null : $this->namespaceMap[$namespace],
                     $localName,
                     null
                 );
             } else {
-
                 // An empty namespace means it's the global namespace. This is
                 // allowed, but it mustn't get a prefix.
-                if ($namespace === "" || $namespace === null) {
+                if ('' === $namespace || null === $namespace) {
                     $result = $this->startElement($localName);
                     $this->writeAttribute('xmlns', '');
                 } else {
                     if (!isset($this->adhocNamespaces[$namespace])) {
-                        $this->adhocNamespaces[$namespace] = 'x' . (count($this->adhocNamespaces) + 1);
+                        $this->adhocNamespaces[$namespace] = 'x'.(count($this->adhocNamespaces) + 1);
                     }
                     $result = $this->startElementNS($this->adhocNamespaces[$namespace], $localName, $namespace);
                 }
             }
-
         } else {
             $result = parent::startElement($name);
         }
 
         if (!$this->namespacesWritten) {
-
             foreach ($this->namespaceMap as $namespace => $prefix) {
-                $this->writeAttribute(($prefix ? 'xmlns:' . $prefix : 'xmlns'), $namespace);
+                $this->writeAttribute(($prefix ? 'xmlns:'.$prefix : 'xmlns'), $namespace);
             }
             $this->namespacesWritten = true;
-
         }
 
         return $result;
-
     }
 
     /**
@@ -182,18 +178,22 @@ class Writer extends XMLWriter {
      *    becomes:
      *    <author xmlns="http://www.w3.org/2005" /><name>Evert Pot</name></author>
      *
-     * @param string $name
-     * @param string $content
+     * Note: this function doesn't have the string typehint, because PHP's
+     * XMLWriter::startElement doesn't either.
+     *
+     * @param array|string|object|null $content
+     *
      * @return bool
      */
-    function writeElement($name, $content = null) {
-
+    public function writeElement($name, $content = null): bool
+    {
         $this->startElement($name);
         if (!is_null($content)) {
             $this->write($content);
         }
         $this->endElement();
 
+        return true;
     }
 
     /**
@@ -204,16 +204,12 @@ class Writer extends XMLWriter {
      * The key is an attribute name. If the key is a 'localName', the current
      * xml namespace is assumed. If it's a 'clark notation key', this namespace
      * will be used instead.
-     *
-     * @param array $attributes
-     * @return void
      */
-    function writeAttributes(array $attributes) {
-
+    public function writeAttributes(array $attributes)
+    {
         foreach ($attributes as $name => $value) {
             $this->writeAttribute($name, $value);
         }
-
     }
 
     /**
@@ -223,44 +219,41 @@ class Writer extends XMLWriter {
      *
      * Returns true when successful.
      *
+     * Note: this function doesn't have typehints, because for some reason
+     * PHP's XMLWriter::writeAttribute doesn't either.
+     *
      * @param string $name
      * @param string $value
-     * @return bool
      */
-    function writeAttribute($name, $value) {
-
-        if ($name[0] === '{') {
-
-            list(
-                $namespace,
-                $localName
-            ) = Service::parseClarkNotation($name);
-
-            if (array_key_exists($namespace, $this->namespaceMap)) {
-                // It's an attribute with a namespace we know
-                $this->writeAttribute(
-                    $this->namespaceMap[$namespace] . ':' . $localName,
-                    $value
-                );
-            } else {
-
-                // We don't know the namespace, we must add it in-line
-                if (!isset($this->adhocNamespaces[$namespace])) {
-                    $this->adhocNamespaces[$namespace] = 'x' . (count($this->adhocNamespaces) + 1);
-                }
-                $this->writeAttributeNS(
-                    $this->adhocNamespaces[$namespace],
-                    $localName,
-                    $namespace,
-                    $value
-                );
+    public function writeAttribute($name, $value): bool
+    {
+        if ('{' !== $name[0]) {
+            return parent::writeAttribute($name, $value);
+        }
 
-            }
+        list(
+            $namespace,
+            $localName
+        ) = Service::parseClarkNotation($name);
+
+        if (array_key_exists($namespace, $this->namespaceMap)) {
+            // It's an attribute with a namespace we know
+            return $this->writeAttribute(
+                $this->namespaceMap[$namespace].':'.$localName,
+                $value
+            );
+        }
 
-        } else {
-            return parent::writeAttribute($name, $value);
+        // We don't know the namespace, we must add it in-line
+        if (!isset($this->adhocNamespaces[$namespace])) {
+            $this->adhocNamespaces[$namespace] = 'x'.(count($this->adhocNamespaces) + 1);
         }
 
+        return $this->writeAttributeNS(
+            $this->adhocNamespaces[$namespace],
+            $localName,
+            $namespace,
+            $value
+        );
     }
-
 }
diff --git a/vendor/sabre/xml/lib/XmlDeserializable.php b/vendor/sabre/xml/lib/XmlDeserializable.php
index fa857e82c..83f33db1e 100644
--- a/vendor/sabre/xml/lib/XmlDeserializable.php
+++ b/vendor/sabre/xml/lib/XmlDeserializable.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Sabre\Xml;
 
 /**
@@ -10,8 +12,8 @@ namespace Sabre\Xml;
  * @author Evert Pot (http://evertpot.com/)
  * @license http://sabre.io/license/ Modified BSD License
  */
-interface XmlDeserializable {
-
+interface XmlDeserializable
+{
     /**
      * The deserialize method is called during xml parsing.
      *
@@ -30,9 +32,7 @@ interface XmlDeserializable {
      * $reader->parseInnerTree() will parse the entire sub-tree, and advance to
      * the next element.
      *
-     * @param Reader $reader
      * @return mixed
      */
-    static function xmlDeserialize(Reader $reader);
-
+    public static function xmlDeserialize(Reader $reader);
 }
diff --git a/vendor/sabre/xml/lib/XmlSerializable.php b/vendor/sabre/xml/lib/XmlSerializable.php
index 3e2c528b9..b22f8d5e8 100644
--- a/vendor/sabre/xml/lib/XmlSerializable.php
+++ b/vendor/sabre/xml/lib/XmlSerializable.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Sabre\Xml;
 
 /**
@@ -10,8 +12,8 @@ namespace Sabre\Xml;
  * @author Evert Pot (http://evertpot.com/)
  * @license http://sabre.io/license/ Modified BSD License
  */
-interface XmlSerializable {
-
+interface XmlSerializable
+{
     /**
      * The xmlSerialize method is called during xml writing.
      *
@@ -27,10 +29,6 @@ interface XmlSerializable {
      * This allows serializers to be re-used for different element names.
      *
      * If you are opening new elements, you must also close them again.
-     *
-     * @param Writer $writer
-     * @return void
      */
-    function xmlSerialize(Writer $writer);
-
+    public function xmlSerialize(Writer $writer);
 }