Change default value of ConsoleInputOption to null.

src/Console/ConsoleInputOption.php

@@ -58,7 +58,7 @@ class ConsoleInputOption
     /**
      * Default value for the option
      *
-     * @var string|bool
+     * @var string|bool|null
      */
     protected $_default;
 
@@ -83,7 +83,7 @@ class ConsoleInputOption
      * @param string $short The short alias for this option
      * @param string $help The help text for this option
      * @param bool $boolean Whether this option is a boolean option. Boolean options don't consume extra tokens
-     * @param string|bool $default The default value for this option.
+     * @param string|bool|null $default The default value for this option.
      * @param string[] $choices Valid choices for this option.
      * @param bool $multiple Whether this option can accept multiple value definition.
      * @throws \Cake\Console\Exception\ConsoleException
@@ -93,7 +93,7 @@ class ConsoleInputOption
         string $short = '',
         string $help = '',
         bool $boolean = false,
-        $default = '',
+        $default = null,
         array $choices = [],
         bool $multiple = false
     ) {
@@ -101,10 +101,15 @@ class ConsoleInputOption
         $this->_short = $short;
         $this->_help = $help;
         $this->_boolean = $boolean;
-        $this->_default = is_bool($default) ? $default : (string)$default;
         $this->_choices = $choices;
         $this->_multiple = $multiple;
 
+        if ($boolean) {
+            $this->_default = (bool)$default;
+        } elseif ($default !== null) {
+            $this->_default = (string)$default;
+        }
+
         if (strlen($this->_short) > 1) {
             throw new ConsoleException(
                 sprintf('Short option "%s" is invalid, short options must be one letter.', $this->_short)
@@ -167,7 +172,7 @@ class ConsoleInputOption
     {
         $name = strlen($this->_short) > 0 ? ('-' . $this->_short) : ('--' . $this->_name);
         $default = '';
-        if (!is_bool($this->_default) && strlen($this->_default) > 0) {
+        if ($this->_default !== null && !is_bool($this->_default) && strlen($this->_default) > 0) {
             $default = ' ' . $this->_default;
         }
         if ($this->_choices) {
@@ -180,7 +185,7 @@ class ConsoleInputOption
     /**
      * Get the default value for this option
      *
-     * @return string|bool
+     * @return string|bool|null
      */
     public function defaultValue()
     {
@@ -194,7 +199,7 @@ class ConsoleInputOption
      */
     public function isBoolean(): bool
     {
-        return (bool)$this->_boolean;
+        return $this->_boolean;
     }
 
     /**
@@ -204,7 +209,7 @@ class ConsoleInputOption
      */
     public function acceptsMultiple(): bool
     {
-        return (bool)$this->_multiple;
+        return $this->_multiple;
     }
 
     /**
@@ -256,7 +261,7 @@ class ConsoleInputOption
         $option->addAttribute('short', $short);
         $option->addAttribute('help', $this->_help);
         $option->addAttribute('boolean', (string)(int)$this->_boolean);
-        $option->addChild('default', $default);
+        $option->addChild('default', (string)$default);
         $choices = $option->addChild('choices');
         foreach ($this->_choices as $valid) {
             $choices->addChild('choice', $valid);

src/Console/ConsoleOptionParser.php

@@ -885,7 +885,7 @@ class ConsoleOptionParser
         } elseif ($isBoolean) {
             $value = true;
         } else {
-            $value = $option->defaultValue();
+            $value = (string)$option->defaultValue();
         }
 
         $option->validChoice($value);

tests/TestCase/Console/ConsoleOptionParserTest.php

@@ -153,11 +153,18 @@ class ConsoleOptionParserTest extends TestCase
     public function testAddOptionDefault()
     {
         $parser = new ConsoleOptionParser('test', false);
-        $parser->addOption('test', [
-            'default' => 'default value',
-        ]);
+        $parser
+            ->addOption('test', [
+                'default' => 'default value',
+            ])
+            ->addOption('no-default', [
+            ]);
         $result = $parser->parse(['--test']);
-        $this->assertEquals(['test' => 'default value', 'help' => false], $result[0], 'Default value did not parse out');
+        $this->assertEquals(
+            ['test' => 'default value', 'help' => false, 'no-default' => null],
+            $result[0],
+            'Default value did not parse out'
+        );
 
         $parser = new ConsoleOptionParser('test', false);
         $parser->addOption('test', [