minor #29009 SCA: simplify some ifs in favour of null coalescing operator (kalessil, vladimir.reznichenko)

This PR was merged into the 4.1 branch.

Discussion
----------

SCA: simplify some ifs in favour of null coalescing operator

| Q             | A
| ------------- | ---
| Branch?       | 4.1
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | n/a
| License       | MIT
| Doc PR        | n/a

Some of ifs were replaced with null coalescing operator in order to simplify control flow.

Commits
-------

636a872389 SCA: reverted code style changes
c926b1abd3 SCA: reverted code style changes
300b31fa75 SCA: applied requested code style changes
0180cb936f SCA: simplify some ifs in favour of null coalescing operator

src/Symfony/Bundle/SecurityBundle/DependencyInjection/SecurityExtension.php

@@ -283,11 +283,7 @@ class SecurityExtension extends Extension
         $contextKey = null;
         // Context serializer listener
         if (false === $firewall['stateless']) {
-            $contextKey = $id;
-            if (isset($firewall['context'])) {
-                $contextKey = $firewall['context'];
-            }
-
+            $contextKey = $firewall['context'] ?? $id;
             $listeners[] = new Reference($this->createContextListener($container, $contextKey));
             $sessionStrategyId = 'security.authentication.session_strategy';
         } else {

src/Symfony/Component/Console/Helper/Table.php

@@ -180,11 +180,7 @@ class Table
      */
     public function getColumnStyle($columnIndex)
     {
-        if (isset($this->columnStyles[$columnIndex])) {
-            return $this->columnStyles[$columnIndex];
-        }
-
-        return $this->getStyle();
+        return $this->columnStyles[$columnIndex] ?? $this->getStyle();
     }
 
     /**

src/Symfony/Component/Filesystem/Filesystem.php

@@ -557,10 +557,7 @@ class Filesystem
             }
         }
 
-        $copyOnWindows = false;
-        if (isset($options['copy_on_windows'])) {
-            $copyOnWindows = $options['copy_on_windows'];
-        }
+        $copyOnWindows = $options['copy_on_windows'] ?? false;
 
         if (null === $iterator) {
             $flags = $copyOnWindows ? \FilesystemIterator::SKIP_DOTS | \FilesystemIterator::FOLLOW_SYMLINKS : \FilesystemIterator::SKIP_DOTS;

src/Symfony/Component/Intl/Globals/IntlGlobals.php

@@ -100,11 +100,7 @@ abstract class IntlGlobals
      */
     public static function getErrorName($code)
     {
-        if (isset(self::$errorCodes[$code])) {
-            return self::$errorCodes[$code];
-        }
-
-        return '[BOGUS UErrorCode]';
+        return self::$errorCodes[$code] ?? '[BOGUS UErrorCode]';
     }
 
     /**

src/Symfony/Component/Messenger/Asynchronous/Routing/SenderLocator.php

@@ -57,10 +57,7 @@ class SenderLocator implements SenderLocatorInterface
         if ($interfaceMapping = array_intersect_key($mapping, class_implements($message))) {
             return current($interfaceMapping);
         }
-        if (isset($mapping['*'])) {
-            return $mapping['*'];
-        }
 
-        return null;
+        return $mapping['*'] ?? null;
     }
 }

src/Symfony/Component/Routing/Generator/UrlGenerator.php

@@ -254,10 +254,7 @@ class UrlGenerator implements UrlGeneratorInterface, ConfigurableRequirementsInt
         });
 
         // extract fragment
-        $fragment = '';
-        if (isset($defaults['_fragment'])) {
-            $fragment = $defaults['_fragment'];
-        }
+        $fragment = $defaults['_fragment'] ?? '';
 
         if (isset($extra['_fragment'])) {
             $fragment = $extra['_fragment'];

src/Symfony/Component/Serializer/Encoder/XmlEncoder.php

@@ -326,11 +326,7 @@ class XmlEncoder implements EncoderInterface, DecoderInterface, NormalizationAwa
             $val = $this->parseXml($subnode, $context);
 
             if ('item' === $subnode->nodeName && isset($val['@key'])) {
-                if (isset($val['#'])) {
-                    $value[$val['@key']] = $val['#'];
-                } else {
-                    $value[$val['@key']] = $val;
-                }
+                $value[$val['@key']] = $val['#'] ?? $val;
             } else {
                 $value[$subnode->nodeName][] = $val;
             }

src/Symfony/Component/Serializer/Mapping/ClassDiscriminatorMapping.php

@@ -32,11 +32,7 @@ class ClassDiscriminatorMapping
 
     public function getClassForType(string $type): ?string
     {
-        if (isset($this->typesMapping[$type])) {
-            return $this->typesMapping[$type];
-        }
-
-        return null;
+        return $this->typesMapping[$type] ?? null;
     }
 
     /**

src/Symfony/Component/Translation/Dumper/JsonFileDumper.php

@@ -25,11 +25,7 @@ class JsonFileDumper extends FileDumper
      */
     public function formatCatalogue(MessageCatalogue $messages, $domain, array $options = array())
     {
-        if (isset($options['json_encoding'])) {
-            $flags = $options['json_encoding'];
-        } else {
-            $flags = JSON_PRETTY_PRINT;
-        }
+        $flags = $options['json_encoding'] ?? JSON_PRETTY_PRINT;
 
         return json_encode($messages->all($domain), $flags);
     }