diff --git a/Application.php b/Application.php
index 07cc6d674..9df983cc8 100644
--- a/Application.php
+++ b/Application.php
@@ -137,7 +137,7 @@ public function setSignalsToDispatchEvent(int ...$signalsToDispatchEvent): void
      *
      * @throws \Exception When running fails. Bypass this when {@link setCatchExceptions()}.
      */
-    public function run(InputInterface $input = null, OutputInterface $output = null): int
+    public function run(?InputInterface $input = null, ?OutputInterface $output = null): int
     {
         if (\function_exists('putenv')) {
             @putenv('LINES='.$this->terminal->getHeight());
@@ -762,7 +762,7 @@ public function find(string $name): Command
      *
      * @return Command[]
      */
-    public function all(string $namespace = null): array
+    public function all(?string $namespace = null): array
     {
         $this->init();
 
@@ -1130,7 +1130,7 @@ private function getAbbreviationSuggestions(array $abbrevs): string
      *
      * This method is not part of public API and should not be used directly.
      */
-    public function extractNamespace(string $name, int $limit = null): string
+    public function extractNamespace(string $name, ?int $limit = null): string
     {
         $parts = explode(':', $name, -1);
 
diff --git a/CI/GithubActionReporter.php b/CI/GithubActionReporter.php
index 7e5565469..2cae6fd8b 100644
--- a/CI/GithubActionReporter.php
+++ b/CI/GithubActionReporter.php
@@ -57,7 +57,7 @@ public static function isGithubActionEnvironment(): bool
      *
      * @see https://docs.github.com/en/free-pro-team@latest/actions/reference/workflow-commands-for-github-actions#setting-an-error-message
      */
-    public function error(string $message, string $file = null, int $line = null, int $col = null): void
+    public function error(string $message, ?string $file = null, ?int $line = null, ?int $col = null): void
     {
         $this->log('error', $message, $file, $line, $col);
     }
@@ -67,7 +67,7 @@ public function error(string $message, string $file = null, int $line = null, in
      *
      * @see https://docs.github.com/en/free-pro-team@latest/actions/reference/workflow-commands-for-github-actions#setting-a-warning-message
      */
-    public function warning(string $message, string $file = null, int $line = null, int $col = null): void
+    public function warning(string $message, ?string $file = null, ?int $line = null, ?int $col = null): void
     {
         $this->log('warning', $message, $file, $line, $col);
     }
@@ -77,12 +77,12 @@ public function warning(string $message, string $file = null, int $line = null,
      *
      * @see https://docs.github.com/en/free-pro-team@latest/actions/reference/workflow-commands-for-github-actions#setting-a-debug-message
      */
-    public function debug(string $message, string $file = null, int $line = null, int $col = null): void
+    public function debug(string $message, ?string $file = null, ?int $line = null, ?int $col = null): void
     {
         $this->log('debug', $message, $file, $line, $col);
     }
 
-    private function log(string $type, string $message, string $file = null, int $line = null, int $col = null): void
+    private function log(string $type, string $message, ?string $file = null, ?int $line = null, ?int $col = null): void
     {
         // Some values must be encoded.
         $message = strtr($message, self::ESCAPED_DATA);
diff --git a/Command/Command.php b/Command/Command.php
index c49891777..07b56ec16 100644
--- a/Command/Command.php
+++ b/Command/Command.php
@@ -77,7 +77,7 @@ public static function getDefaultDescription(): ?string
      *
      * @throws LogicException When the command name is empty
      */
-    public function __construct(string $name = null)
+    public function __construct(?string $name = null)
     {
         $this->definition = new InputDefinition();
 
@@ -413,7 +413,7 @@ public function getNativeDefinition(): InputDefinition
      *
      * @throws InvalidArgumentException When argument mode is not valid
      */
-    public function addArgument(string $name, int $mode = null, string $description = '', mixed $default = null, array|\Closure $suggestedValues = []): static
+    public function addArgument(string $name, ?int $mode = null, string $description = '', mixed $default = null, array|\Closure $suggestedValues = []): static
     {
         $this->definition->addArgument(new InputArgument($name, $mode, $description, $default, $suggestedValues));
         $this->fullDefinition?->addArgument(new InputArgument($name, $mode, $description, $default, $suggestedValues));
@@ -433,7 +433,7 @@ public function addArgument(string $name, int $mode = null, string $description
      *
      * @throws InvalidArgumentException If option mode is invalid or incompatible
      */
-    public function addOption(string $name, string|array $shortcut = null, int $mode = null, string $description = '', mixed $default = null, array|\Closure $suggestedValues = []): static
+    public function addOption(string $name, string|array|null $shortcut = null, ?int $mode = null, string $description = '', mixed $default = null, array|\Closure $suggestedValues = []): static
     {
         $this->definition->addOption(new InputOption($name, $shortcut, $mode, $description, $default, $suggestedValues));
         $this->fullDefinition?->addOption(new InputOption($name, $shortcut, $mode, $description, $default, $suggestedValues));
diff --git a/Command/LazyCommand.php b/Command/LazyCommand.php
index 7279724a6..d2fe8a1b6 100644
--- a/Command/LazyCommand.php
+++ b/Command/LazyCommand.php
@@ -113,7 +113,7 @@ public function getNativeDefinition(): InputDefinition
     /**
      * @param array|\Closure(CompletionInput,CompletionSuggestions):list<string|Suggestion> $suggestedValues The values used for input completion
      */
-    public function addArgument(string $name, int $mode = null, string $description = '', mixed $default = null, array|\Closure $suggestedValues = []): static
+    public function addArgument(string $name, ?int $mode = null, string $description = '', mixed $default = null, array|\Closure $suggestedValues = []): static
     {
         $this->getCommand()->addArgument($name, $mode, $description, $default, $suggestedValues);
 
@@ -123,7 +123,7 @@ public function addArgument(string $name, int $mode = null, string $description
     /**
      * @param array|\Closure(CompletionInput,CompletionSuggestions):list<string|Suggestion> $suggestedValues The values used for input completion
      */
-    public function addOption(string $name, string|array $shortcut = null, int $mode = null, string $description = '', mixed $default = null, array|\Closure $suggestedValues = []): static
+    public function addOption(string $name, string|array|null $shortcut = null, ?int $mode = null, string $description = '', mixed $default = null, array|\Closure $suggestedValues = []): static
     {
         $this->getCommand()->addOption($name, $shortcut, $mode, $description, $default, $suggestedValues);
 
diff --git a/Command/LockableTrait.php b/Command/LockableTrait.php
index c1006a65c..cd7548f02 100644
--- a/Command/LockableTrait.php
+++ b/Command/LockableTrait.php
@@ -29,7 +29,7 @@ trait LockableTrait
     /**
      * Locks a command.
      */
-    private function lock(string $name = null, bool $blocking = false): bool
+    private function lock(?string $name = null, bool $blocking = false): bool
     {
         if (!class_exists(SemaphoreStore::class)) {
             throw new LogicException('To enable the locking feature you must install the symfony/lock component. Try running "composer require symfony/lock".');
diff --git a/Command/TraceableCommand.php b/Command/TraceableCommand.php
index d8c46b7fa..9ffb68da3 100644
--- a/Command/TraceableCommand.php
+++ b/Command/TraceableCommand.php
@@ -134,7 +134,7 @@ public function ignoreValidationErrors(): void
         parent::ignoreValidationErrors();
     }
 
-    public function setApplication(Application $application = null): void
+    public function setApplication(?Application $application = null): void
     {
         $this->command->setApplication($application);
     }
@@ -209,14 +209,14 @@ public function getNativeDefinition(): InputDefinition
         return $this->command->getNativeDefinition();
     }
 
-    public function addArgument(string $name, int $mode = null, string $description = '', mixed $default = null, array|\Closure $suggestedValues = []): static
+    public function addArgument(string $name, ?int $mode = null, string $description = '', mixed $default = null, array|\Closure $suggestedValues = []): static
     {
         $this->command->addArgument($name, $mode, $description, $default, $suggestedValues);
 
         return $this;
     }
 
-    public function addOption(string $name, string|array $shortcut = null, int $mode = null, string $description = '', mixed $default = null, array|\Closure $suggestedValues = []): static
+    public function addOption(string $name, string|array|null $shortcut = null, ?int $mode = null, string $description = '', mixed $default = null, array|\Closure $suggestedValues = []): static
     {
         $this->command->addOption($name, $shortcut, $mode, $description, $default, $suggestedValues);
 
diff --git a/DataCollector/CommandDataCollector.php b/DataCollector/CommandDataCollector.php
index 16a0eadf4..45138c7dc 100644
--- a/DataCollector/CommandDataCollector.php
+++ b/DataCollector/CommandDataCollector.php
@@ -27,7 +27,7 @@
  */
 final class CommandDataCollector extends DataCollector
 {
-    public function collect(Request $request, Response $response, \Throwable $exception = null): void
+    public function collect(Request $request, Response $response, ?\Throwable $exception = null): void
     {
         if (!$request instanceof CliRequest) {
             return;
diff --git a/Descriptor/ApplicationDescription.php b/Descriptor/ApplicationDescription.php
index f8ed18045..ef9e8a63b 100644
--- a/Descriptor/ApplicationDescription.php
+++ b/Descriptor/ApplicationDescription.php
@@ -39,7 +39,7 @@ class ApplicationDescription
      */
     private array $aliases = [];
 
-    public function __construct(Application $application, string $namespace = null, bool $showHidden = false)
+    public function __construct(Application $application, ?string $namespace = null, bool $showHidden = false)
     {
         $this->application = $application;
         $this->namespace = $namespace;
diff --git a/Descriptor/XmlDescriptor.php b/Descriptor/XmlDescriptor.php
index 72580fd98..866c71856 100644
--- a/Descriptor/XmlDescriptor.php
+++ b/Descriptor/XmlDescriptor.php
@@ -79,7 +79,7 @@ public function getCommandDocument(Command $command, bool $short = false): \DOMD
         return $dom;
     }
 
-    public function getApplicationDocument(Application $application, string $namespace = null, bool $short = false): \DOMDocument
+    public function getApplicationDocument(Application $application, ?string $namespace = null, bool $short = false): \DOMDocument
     {
         $dom = new \DOMDocument('1.0', 'UTF-8');
         $dom->appendChild($rootXml = $dom->createElement('symfony'));
diff --git a/Event/ConsoleErrorEvent.php b/Event/ConsoleErrorEvent.php
index d4a691216..7be2ff83e 100644
--- a/Event/ConsoleErrorEvent.php
+++ b/Event/ConsoleErrorEvent.php
@@ -25,7 +25,7 @@ final class ConsoleErrorEvent extends ConsoleEvent
     private \Throwable $error;
     private int $exitCode;
 
-    public function __construct(InputInterface $input, OutputInterface $output, \Throwable $error, Command $command = null)
+    public function __construct(InputInterface $input, OutputInterface $output, \Throwable $error, ?Command $command = null)
     {
         parent::__construct($command, $input, $output);
 
diff --git a/EventListener/ErrorListener.php b/EventListener/ErrorListener.php
index 5c38e8ef8..1e41e7594 100644
--- a/EventListener/ErrorListener.php
+++ b/EventListener/ErrorListener.php
@@ -26,7 +26,7 @@ class ErrorListener implements EventSubscriberInterface
 {
     private ?LoggerInterface $logger;
 
-    public function __construct(LoggerInterface $logger = null)
+    public function __construct(?LoggerInterface $logger = null)
     {
         $this->logger = $logger;
     }
diff --git a/Exception/CommandNotFoundException.php b/Exception/CommandNotFoundException.php
index 1e9f1c793..541b32b23 100644
--- a/Exception/CommandNotFoundException.php
+++ b/Exception/CommandNotFoundException.php
@@ -26,7 +26,7 @@ class CommandNotFoundException extends \InvalidArgumentException implements Exce
      * @param int             $code         Exception code
      * @param \Throwable|null $previous     Previous exception used for the exception chaining
      */
-    public function __construct(string $message, array $alternatives = [], int $code = 0, \Throwable $previous = null)
+    public function __construct(string $message, array $alternatives = [], int $code = 0, ?\Throwable $previous = null)
     {
         parent::__construct($message, $code, $previous);
 
diff --git a/Formatter/OutputFormatterStyle.php b/Formatter/OutputFormatterStyle.php
index 4582ccd05..20a65b517 100644
--- a/Formatter/OutputFormatterStyle.php
+++ b/Formatter/OutputFormatterStyle.php
@@ -33,7 +33,7 @@ class OutputFormatterStyle implements OutputFormatterStyleInterface
      * @param string|null $foreground The style foreground color name
      * @param string|null $background The style background color name
      */
-    public function __construct(string $foreground = null, string $background = null, array $options = [])
+    public function __construct(?string $foreground = null, ?string $background = null, array $options = [])
     {
         $this->color = new Color($this->foreground = $foreground ?: '', $this->background = $background ?: '', $this->options = $options);
     }
diff --git a/Formatter/OutputFormatterStyleStack.php b/Formatter/OutputFormatterStyleStack.php
index c3726a35d..4985213ab 100644
--- a/Formatter/OutputFormatterStyleStack.php
+++ b/Formatter/OutputFormatterStyleStack.php
@@ -26,7 +26,7 @@ class OutputFormatterStyleStack implements ResetInterface
 
     private OutputFormatterStyleInterface $emptyStyle;
 
-    public function __construct(OutputFormatterStyleInterface $emptyStyle = null)
+    public function __construct(?OutputFormatterStyleInterface $emptyStyle = null)
     {
         $this->emptyStyle = $emptyStyle ?? new OutputFormatterStyle();
         $this->reset();
@@ -53,7 +53,7 @@ public function push(OutputFormatterStyleInterface $style): void
      *
      * @throws InvalidArgumentException When style tags incorrectly nested
      */
-    public function pop(OutputFormatterStyleInterface $style = null): OutputFormatterStyleInterface
+    public function pop(?OutputFormatterStyleInterface $style = null): OutputFormatterStyleInterface
     {
         if (!$this->styles) {
             return $this->emptyStyle;
diff --git a/Helper/Dumper.php b/Helper/Dumper.php
index 8c6a94d51..a3b8e3952 100644
--- a/Helper/Dumper.php
+++ b/Helper/Dumper.php
@@ -26,7 +26,7 @@ final class Dumper
     private ?ClonerInterface $cloner;
     private \Closure $handler;
 
-    public function __construct(OutputInterface $output, CliDumper $dumper = null, ClonerInterface $cloner = null)
+    public function __construct(OutputInterface $output, ?CliDumper $dumper = null, ?ClonerInterface $cloner = null)
     {
         $this->output = $output;
         $this->dumper = $dumper;
diff --git a/Helper/Helper.php b/Helper/Helper.php
index afb20ad50..de090063a 100644
--- a/Helper/Helper.php
+++ b/Helper/Helper.php
@@ -74,7 +74,7 @@ public static function length(?string $string): int
     /**
      * Returns the subset of a string, using mb_substr if it is available.
      */
-    public static function substr(?string $string, int $from, int $length = null): string
+    public static function substr(?string $string, int $from, ?int $length = null): string
     {
         $string ??= '';
 
diff --git a/Helper/HelperSet.php b/Helper/HelperSet.php
index 42153b68d..30df9f958 100644
--- a/Helper/HelperSet.php
+++ b/Helper/HelperSet.php
@@ -35,7 +35,7 @@ public function __construct(array $helpers = [])
         }
     }
 
-    public function set(HelperInterface $helper, string $alias = null): void
+    public function set(HelperInterface $helper, ?string $alias = null): void
     {
         $this->helpers[$helper->getName()] = $helper;
         if (null !== $alias) {
diff --git a/Helper/ProcessHelper.php b/Helper/ProcessHelper.php
index 26d35a1a8..3ef6f71f7 100644
--- a/Helper/ProcessHelper.php
+++ b/Helper/ProcessHelper.php
@@ -32,7 +32,7 @@ class ProcessHelper extends Helper
      * @param callable|null $callback A PHP callback to run whenever there is some
      *                                output available on STDOUT or STDERR
      */
-    public function run(OutputInterface $output, array|Process $cmd, string $error = null, callable $callback = null, int $verbosity = OutputInterface::VERBOSITY_VERY_VERBOSE): Process
+    public function run(OutputInterface $output, array|Process $cmd, ?string $error = null, ?callable $callback = null, int $verbosity = OutputInterface::VERBOSITY_VERY_VERBOSE): Process
     {
         if (!class_exists(Process::class)) {
             throw new \LogicException('The ProcessHelper cannot be run as the Process component is not installed. Try running "compose require symfony/process".');
@@ -94,7 +94,7 @@ public function run(OutputInterface $output, array|Process $cmd, string $error =
      *
      * @see run()
      */
-    public function mustRun(OutputInterface $output, array|Process $cmd, string $error = null, callable $callback = null): Process
+    public function mustRun(OutputInterface $output, array|Process $cmd, ?string $error = null, ?callable $callback = null): Process
     {
         $process = $this->run($output, $cmd, $error, $callback);
 
@@ -108,7 +108,7 @@ public function mustRun(OutputInterface $output, array|Process $cmd, string $err
     /**
      * Wraps a Process callback to add debugging output.
      */
-    public function wrapCallback(OutputInterface $output, Process $process, callable $callback = null): callable
+    public function wrapCallback(OutputInterface $output, Process $process, ?callable $callback = null): callable
     {
         if ($output instanceof ConsoleOutputInterface) {
             $output = $output->getErrorOutput();
diff --git a/Helper/ProgressBar.php b/Helper/ProgressBar.php
index 64389c4a2..f4eec051c 100644
--- a/Helper/ProgressBar.php
+++ b/Helper/ProgressBar.php
@@ -313,7 +313,7 @@ public function maxSecondsBetweenRedraws(float $seconds): void
      *
      * @return iterable<TKey, TValue>
      */
-    public function iterate(iterable $iterable, int $max = null): iterable
+    public function iterate(iterable $iterable, ?int $max = null): iterable
     {
         $this->start($max ?? (is_countable($iterable) ? \count($iterable) : 0));
 
@@ -332,7 +332,7 @@ public function iterate(iterable $iterable, int $max = null): iterable
      * @param int|null $max     Number of steps to complete the bar (0 if indeterminate), null to leave unchanged
      * @param int      $startAt The starting point of the bar (useful e.g. when resuming a previously started bar)
      */
-    public function start(int $max = null, int $startAt = 0): void
+    public function start(?int $max = null, int $startAt = 0): void
     {
         $this->startTime = time();
         $this->step = $startAt;
diff --git a/Helper/ProgressIndicator.php b/Helper/ProgressIndicator.php
index 8865ecc34..2ffac2ec9 100644
--- a/Helper/ProgressIndicator.php
+++ b/Helper/ProgressIndicator.php
@@ -50,7 +50,7 @@ class ProgressIndicator
      * @param int        $indicatorChangeInterval Change interval in milliseconds
      * @param array|null $indicatorValues         Animated indicator characters
      */
-    public function __construct(OutputInterface $output, string $format = null, int $indicatorChangeInterval = 100, array $indicatorValues = null)
+    public function __construct(OutputInterface $output, ?string $format = null, int $indicatorChangeInterval = 100, ?array $indicatorValues = null)
     {
         $this->output = $output;
 
diff --git a/Helper/Table.php b/Helper/Table.php
index fe2ac87c1..e71e83ac3 100644
--- a/Helper/Table.php
+++ b/Helper/Table.php
@@ -462,7 +462,7 @@ public function render(): void
      *
      *     +-----+-----------+-------+
      */
-    private function renderRowSeparator(int $type = self::SEPARATOR_MID, string $title = null, string $titleFormat = null): void
+    private function renderRowSeparator(int $type = self::SEPARATOR_MID, ?string $title = null, ?string $titleFormat = null): void
     {
         if (!$count = $this->numberOfColumns) {
             return;
@@ -527,7 +527,7 @@ private function renderColumnSeparator(int $type = self::BORDER_OUTSIDE): string
      *
      *     | 9971-5-0210-0 | A Tale of Two Cities  | Charles Dickens  |
      */
-    private function renderRow(array $row, string $cellFormat, string $firstCellFormat = null): void
+    private function renderRow(array $row, string $cellFormat, ?string $firstCellFormat = null): void
     {
         $rowContent = $this->renderColumnSeparator(self::BORDER_OUTSIDE);
         $columns = $this->getRowColumns($row);
diff --git a/Helper/TableStyle.php b/Helper/TableStyle.php
index bbad98e73..be956c109 100644
--- a/Helper/TableStyle.php
+++ b/Helper/TableStyle.php
@@ -88,7 +88,7 @@ public function getPaddingChar(): string
      *
      * @return $this
      */
-    public function setHorizontalBorderChars(string $outside, string $inside = null): static
+    public function setHorizontalBorderChars(string $outside, ?string $inside = null): static
     {
         $this->horizontalOutsideBorderChar = $outside;
         $this->horizontalInsideBorderChar = $inside ?? $outside;
@@ -113,7 +113,7 @@ public function setHorizontalBorderChars(string $outside, string $inside = null)
      *
      * @return $this
      */
-    public function setVerticalBorderChars(string $outside, string $inside = null): static
+    public function setVerticalBorderChars(string $outside, ?string $inside = null): static
     {
         $this->verticalOutsideBorderChar = $outside;
         $this->verticalInsideBorderChar = $inside ?? $outside;
@@ -167,7 +167,7 @@ public function getBorderChars(): array
      *
      * @return $this
      */
-    public function setCrossingChars(string $cross, string $topLeft, string $topMid, string $topRight, string $midRight, string $bottomRight, string $bottomMid, string $bottomLeft, string $midLeft, string $topLeftBottom = null, string $topMidBottom = null, string $topRightBottom = null): static
+    public function setCrossingChars(string $cross, string $topLeft, string $topMid, string $topRight, string $midRight, string $bottomRight, string $bottomMid, string $bottomLeft, string $midLeft, ?string $topLeftBottom = null, ?string $topMidBottom = null, ?string $topRightBottom = null): static
     {
         $this->crossingChar = $cross;
         $this->crossingTopLeftChar = $topLeft;
diff --git a/Input/ArgvInput.php b/Input/ArgvInput.php
index 9ae2f54f5..8621d62cf 100644
--- a/Input/ArgvInput.php
+++ b/Input/ArgvInput.php
@@ -43,7 +43,7 @@ class ArgvInput extends Input
     private array $tokens;
     private array $parsed;
 
-    public function __construct(array $argv = null, InputDefinition $definition = null)
+    public function __construct(?array $argv = null, ?InputDefinition $definition = null)
     {
         $argv ??= $_SERVER['argv'] ?? [];
 
diff --git a/Input/ArrayInput.php b/Input/ArrayInput.php
index 03b200b13..9f1fdafc7 100644
--- a/Input/ArrayInput.php
+++ b/Input/ArrayInput.php
@@ -27,7 +27,7 @@ class ArrayInput extends Input
 {
     private array $parameters;
 
-    public function __construct(array $parameters, InputDefinition $definition = null)
+    public function __construct(array $parameters, ?InputDefinition $definition = null)
     {
         $this->parameters = $parameters;
 
diff --git a/Input/Input.php b/Input/Input.php
index 6a9248b7a..5a8b9a27a 100644
--- a/Input/Input.php
+++ b/Input/Input.php
@@ -34,7 +34,7 @@ abstract class Input implements InputInterface, StreamableInputInterface
     protected array $arguments = [];
     protected bool $interactive = true;
 
-    public function __construct(InputDefinition $definition = null)
+    public function __construct(?InputDefinition $definition = null)
     {
         if (null === $definition) {
             $this->definition = new InputDefinition();
diff --git a/Input/InputArgument.php b/Input/InputArgument.php
index 642ae6600..bcc464c96 100644
--- a/Input/InputArgument.php
+++ b/Input/InputArgument.php
@@ -44,7 +44,7 @@ class InputArgument
      *
      * @throws InvalidArgumentException When argument mode is not valid
      */
-    public function __construct(string $name, int $mode = null, string $description = '', string|bool|int|float|array $default = null, \Closure|array $suggestedValues = [])
+    public function __construct(string $name, ?int $mode = null, string $description = '', string|bool|int|float|array|null $default = null, \Closure|array $suggestedValues = [])
     {
         if (null === $mode) {
             $mode = self::OPTIONAL;
diff --git a/Input/InputOption.php b/Input/InputOption.php
index f8e9b0dd6..cc2115d0e 100644
--- a/Input/InputOption.php
+++ b/Input/InputOption.php
@@ -65,7 +65,7 @@ class InputOption
      *
      * @throws InvalidArgumentException If option mode is invalid or incompatible
      */
-    public function __construct(string $name, string|array $shortcut = null, int $mode = null, string $description = '', string|bool|int|float|array $default = null, array|\Closure $suggestedValues = [])
+    public function __construct(string $name, string|array|null $shortcut = null, ?int $mode = null, string $description = '', string|bool|int|float|array|null $default = null, array|\Closure $suggestedValues = [])
     {
         if (str_starts_with($name, '--')) {
             $name = substr($name, 2);
@@ -75,7 +75,7 @@ public function __construct(string $name, string|array $shortcut = null, int $mo
             throw new InvalidArgumentException('An option name cannot be empty.');
         }
 
-        if (empty($shortcut)) {
+        if ('' === $shortcut || [] === $shortcut) {
             $shortcut = null;
         }
 
@@ -84,10 +84,10 @@ public function __construct(string $name, string|array $shortcut = null, int $mo
                 $shortcut = implode('|', $shortcut);
             }
             $shortcuts = preg_split('{(\|)-?}', ltrim($shortcut, '-'));
-            $shortcuts = array_filter($shortcuts);
+            $shortcuts = array_filter($shortcuts, 'strlen');
             $shortcut = implode('|', $shortcuts);
 
-            if (empty($shortcut)) {
+            if ('' === $shortcut) {
                 throw new InvalidArgumentException('An option shortcut cannot be empty.');
             }
         }
diff --git a/Output/ConsoleOutput.php b/Output/ConsoleOutput.php
index f9e6c7710..2ad3dbcf3 100644
--- a/Output/ConsoleOutput.php
+++ b/Output/ConsoleOutput.php
@@ -37,7 +37,7 @@ class ConsoleOutput extends StreamOutput implements ConsoleOutputInterface
      * @param bool|null                     $decorated Whether to decorate messages (null for auto-guessing)
      * @param OutputFormatterInterface|null $formatter Output formatter instance (null to use default OutputFormatter)
      */
-    public function __construct(int $verbosity = self::VERBOSITY_NORMAL, bool $decorated = null, OutputFormatterInterface $formatter = null)
+    public function __construct(int $verbosity = self::VERBOSITY_NORMAL, ?bool $decorated = null, ?OutputFormatterInterface $formatter = null)
     {
         parent::__construct($this->openOutputStream(), $verbosity, $decorated, $formatter);
 
diff --git a/Output/ConsoleSectionOutput.php b/Output/ConsoleSectionOutput.php
index d5b5aff76..ded97c70e 100644
--- a/Output/ConsoleSectionOutput.php
+++ b/Output/ConsoleSectionOutput.php
@@ -61,7 +61,7 @@ public function setMaxHeight(int $maxHeight): void
      *
      * @param int $lines Number of lines to clear. If null, then the entire output of this section is cleared
      */
-    public function clear(int $lines = null): void
+    public function clear(?int $lines = null): void
     {
         if (empty($this->content) || !$this->isDecorated()) {
             return;
diff --git a/Output/Output.php b/Output/Output.php
index fe8564bb9..2bb105748 100644
--- a/Output/Output.php
+++ b/Output/Output.php
@@ -37,7 +37,7 @@ abstract class Output implements OutputInterface
      * @param bool                          $decorated Whether to decorate messages
      * @param OutputFormatterInterface|null $formatter Output formatter instance (null to use default OutputFormatter)
      */
-    public function __construct(?int $verbosity = self::VERBOSITY_NORMAL, bool $decorated = false, OutputFormatterInterface $formatter = null)
+    public function __construct(?int $verbosity = self::VERBOSITY_NORMAL, bool $decorated = false, ?OutputFormatterInterface $formatter = null)
     {
         $this->verbosity = $verbosity ?? self::VERBOSITY_NORMAL;
         $this->formatter = $formatter ?? new OutputFormatter();
diff --git a/Output/StreamOutput.php b/Output/StreamOutput.php
index 55e403d33..304aa1e5d 100644
--- a/Output/StreamOutput.php
+++ b/Output/StreamOutput.php
@@ -40,7 +40,7 @@ class StreamOutput extends Output
      *
      * @throws InvalidArgumentException When first argument is not a real stream
      */
-    public function __construct($stream, int $verbosity = self::VERBOSITY_NORMAL, bool $decorated = null, OutputFormatterInterface $formatter = null)
+    public function __construct($stream, int $verbosity = self::VERBOSITY_NORMAL, ?bool $decorated = null, ?OutputFormatterInterface $formatter = null)
     {
         if (!\is_resource($stream) || 'stream' !== get_resource_type($stream)) {
             throw new InvalidArgumentException('The StreamOutput class needs a stream as its first argument.');
@@ -94,6 +94,10 @@ protected function hasColorSupport(): bool
             return false;
         }
 
+        if (!$this->isTty()) {
+            return false;
+        }
+
         if (\DIRECTORY_SEPARATOR === '\\'
             && \function_exists('sapi_windows_vt100_support')
             && @sapi_windows_vt100_support($this->stream)
@@ -104,7 +108,36 @@ protected function hasColorSupport(): bool
         return 'Hyper' === getenv('TERM_PROGRAM')
             || false !== getenv('ANSICON')
             || 'ON' === getenv('ConEmuANSI')
-            || str_starts_with((string) getenv('TERM'), 'xterm')
-            || stream_isatty($this->stream);
+            || str_starts_with((string) getenv('TERM'), 'xterm');
+    }
+
+    /**
+     * Checks if the stream is a TTY, i.e; whether the output stream is connected to a terminal.
+     *
+     * Reference: Composer\Util\Platform::isTty
+     * https://github.com/composer/composer
+     */
+    private function isTty(): bool
+    {
+        // Detect msysgit/mingw and assume this is a tty because detection
+        // does not work correctly, see https://github.com/composer/composer/issues/9690
+        if (\in_array(strtoupper((string) getenv('MSYSTEM')), ['MINGW32', 'MINGW64'], true)) {
+            return true;
+        }
+
+        // Modern cross-platform function, includes the fstat fallback so if it is present we trust it
+        if (\function_exists('stream_isatty')) {
+            return stream_isatty($this->stream);
+        }
+
+        // Only trusting this if it is positive, otherwise prefer fstat fallback.
+        if (\function_exists('posix_isatty') && posix_isatty($this->stream)) {
+            return true;
+        }
+
+        $stat = @fstat($this->stream);
+
+        // Check if formatted mode is S_IFCHR
+        return $stat ? 0020000 === ($stat['mode'] & 0170000) : false;
     }
 }
diff --git a/Output/TrimmedBufferOutput.php b/Output/TrimmedBufferOutput.php
index 5655e7bc8..c1862a2bd 100644
--- a/Output/TrimmedBufferOutput.php
+++ b/Output/TrimmedBufferOutput.php
@@ -24,7 +24,7 @@ class TrimmedBufferOutput extends Output
     private int $maxLength;
     private string $buffer = '';
 
-    public function __construct(int $maxLength, ?int $verbosity = self::VERBOSITY_NORMAL, bool $decorated = false, OutputFormatterInterface $formatter = null)
+    public function __construct(int $maxLength, ?int $verbosity = self::VERBOSITY_NORMAL, bool $decorated = false, ?OutputFormatterInterface $formatter = null)
     {
         if ($maxLength <= 0) {
             throw new InvalidArgumentException(sprintf('"%s()" expects a strictly positive maxLength. Got %d.', __METHOD__, $maxLength));
diff --git a/Question/Question.php b/Question/Question.php
index c79683cd5..6afe8ea6b 100644
--- a/Question/Question.php
+++ b/Question/Question.php
@@ -36,7 +36,7 @@ class Question
      * @param string                     $question The question to ask to the user
      * @param string|bool|int|float|null $default  The default answer to return if the user enters nothing
      */
-    public function __construct(string $question, string|bool|int|float $default = null)
+    public function __construct(string $question, string|bool|int|float|null $default = null)
     {
         $this->question = $question;
         $this->default = $default;
diff --git a/SingleCommandApplication.php b/SingleCommandApplication.php
index 4f0b5ba3c..ff1c17247 100644
--- a/SingleCommandApplication.php
+++ b/SingleCommandApplication.php
@@ -46,7 +46,7 @@ public function setAutoExit(bool $autoExit): static
         return $this;
     }
 
-    public function run(InputInterface $input = null, OutputInterface $output = null): int
+    public function run(?InputInterface $input = null, ?OutputInterface $output = null): int
     {
         if ($this->running) {
             return parent::run($input, $output);
diff --git a/Style/StyleInterface.php b/Style/StyleInterface.php
index 869b16090..fcc5bc775 100644
--- a/Style/StyleInterface.php
+++ b/Style/StyleInterface.php
@@ -71,12 +71,12 @@ public function table(array $headers, array $rows): void;
     /**
      * Asks a question.
      */
-    public function ask(string $question, string $default = null, callable $validator = null): mixed;
+    public function ask(string $question, ?string $default = null, ?callable $validator = null): mixed;
 
     /**
      * Asks a question with the user input hidden.
      */
-    public function askHidden(string $question, callable $validator = null): mixed;
+    public function askHidden(string $question, ?callable $validator = null): mixed;
 
     /**
      * Asks for confirmation.
diff --git a/Style/SymfonyStyle.php b/Style/SymfonyStyle.php
index 0da5d6981..ca557d6c1 100644
--- a/Style/SymfonyStyle.php
+++ b/Style/SymfonyStyle.php
@@ -61,7 +61,7 @@ public function __construct(InputInterface $input, OutputInterface $output)
     /**
      * Formats a message as a block of text.
      */
-    public function block(string|array $messages, string $type = null, string $style = null, string $prefix = ' ', bool $padding = false, bool $escape = true): void
+    public function block(string|array $messages, ?string $type = null, ?string $style = null, string $prefix = ' ', bool $padding = false, bool $escape = true): void
     {
         $messages = \is_array($messages) ? array_values($messages) : [$messages];
 
@@ -209,7 +209,7 @@ public function definitionList(string|array|TableSeparator ...$list): void
         $this->horizontalTable($headers, [$row]);
     }
 
-    public function ask(string $question, string $default = null, callable $validator = null): mixed
+    public function ask(string $question, ?string $default = null, ?callable $validator = null): mixed
     {
         $question = new Question($question, $default);
         $question->setValidator($validator);
@@ -217,7 +217,7 @@ public function ask(string $question, string $default = null, callable $validato
         return $this->askQuestion($question);
     }
 
-    public function askHidden(string $question, callable $validator = null): mixed
+    public function askHidden(string $question, ?callable $validator = null): mixed
     {
         $question = new Question($question);
 
@@ -287,7 +287,7 @@ public function createProgressBar(int $max = 0): ProgressBar
      *
      * @return iterable<TKey, TValue>
      */
-    public function progressIterate(iterable $iterable, int $max = null): iterable
+    public function progressIterate(iterable $iterable, ?int $max = null): iterable
     {
         yield from $this->createProgressBar()->iterate($iterable, $max);
 
@@ -398,7 +398,7 @@ private function writeBuffer(string $message, bool $newLine, int $type): void
         $this->bufferedOutput->write($message, $newLine, $type);
     }
 
-    private function createBlock(iterable $messages, string $type = null, string $style = null, string $prefix = ' ', bool $padding = false, bool $escape = false): array
+    private function createBlock(iterable $messages, ?string $type = null, ?string $style = null, string $prefix = ' ', bool $padding = false, bool $escape = false): array
     {
         $indentLength = 0;
         $prefixLength = Helper::width(Helper::removeDecoration($this->getFormatter(), $prefix));
diff --git a/Tests/Formatter/OutputFormatterTest.php b/Tests/Formatter/OutputFormatterTest.php
index 610522a7e..f62fa0889 100644
--- a/Tests/Formatter/OutputFormatterTest.php
+++ b/Tests/Formatter/OutputFormatterTest.php
@@ -162,7 +162,7 @@ public function testInlineStyle()
     /**
      * @dataProvider provideInlineStyleOptionsCases
      */
-    public function testInlineStyleOptions(string $tag, string $expected = null, string $input = null, bool $truecolor = false)
+    public function testInlineStyleOptions(string $tag, ?string $expected = null, ?string $input = null, bool $truecolor = false)
     {
         if ($truecolor && 'truecolor' !== getenv('COLORTERM')) {
             $this->markTestSkipped('The terminal does not support true colors.');
diff --git a/Tests/Helper/HelperSetTest.php b/Tests/Helper/HelperSetTest.php
index 9fbb9afca..389ee0ed3 100644
--- a/Tests/Helper/HelperSetTest.php
+++ b/Tests/Helper/HelperSetTest.php
@@ -87,7 +87,7 @@ public function testIteration()
         }
     }
 
-    private function getGenericMockHelper($name, HelperSet $helperset = null)
+    private function getGenericMockHelper($name, ?HelperSet $helperset = null)
     {
         $mock_helper = $this->createMock(HelperInterface::class);
         $mock_helper->expects($this->any())
diff --git a/Tests/Input/InputOptionTest.php b/Tests/Input/InputOptionTest.php
index 74bf69586..e7a007a61 100644
--- a/Tests/Input/InputOptionTest.php
+++ b/Tests/Input/InputOptionTest.php
@@ -59,6 +59,20 @@ public function testShortcut()
         $this->assertEquals('f|ff|fff', $option->getShortcut(), '__construct() removes the leading - of the shortcuts');
         $option = new InputOption('foo');
         $this->assertNull($option->getShortcut(), '__construct() makes the shortcut null by default');
+        $option = new InputOption('foo', '');
+        $this->assertNull($option->getShortcut(), '__construct() makes the shortcut null when given an empty string');
+        $option = new InputOption('foo', []);
+        $this->assertNull($option->getShortcut(), '__construct() makes the shortcut null when given an empty array');
+        $option = new InputOption('foo', ['f', '', 'fff']);
+        $this->assertEquals('f|fff', $option->getShortcut(), '__construct() removes empty shortcuts');
+        $option = new InputOption('foo', 'f||fff');
+        $this->assertEquals('f|fff', $option->getShortcut(), '__construct() removes empty shortcuts');
+        $option = new InputOption('foo', '0');
+        $this->assertEquals('0', $option->getShortcut(), '-0 is an acceptable shortcut value');
+        $option = new InputOption('foo', ['0', 'z']);
+        $this->assertEquals('0|z', $option->getShortcut(), '-0 is an acceptable shortcut value when embedded in an array');
+        $option = new InputOption('foo', '0|z');
+        $this->assertEquals('0|z', $option->getShortcut(), '-0 is an acceptable shortcut value when embedded in a string-list');
     }
 
     public function testModes()