Allow short options. Needed to pass along -vvv

--verbose=3 is not allowed by its InputDefinition. --verbose does not accept a value (i.e. is VALUE_NONE). It must be passed as short option.

So we enable convertOptions() to pass along short options via a magic value `-short`. Magic values of true and false are already supported so hopefully this doesnt smell too bad.

This enables a fix for drush-ops/drush#5909

src/Util/ArgumentProcessor.php

@@ -83,6 +83,8 @@ protected function convertOptions($options)
         foreach ($options as $option => $value) {
             if ($value === true || $value === null) {
                 $result[] = "--$option";
+            } elseif ($value === '-short') {
+                $result[] = "-$option";
             } elseif ($value === false) {
                 // Ignore this option.
             } else {

tests/ArgumentProcessorTest.php

@@ -23,10 +23,10 @@ public function argumentProcessorTestValues()
             ],
 
             [
-                '["drush", "status", "--fields=root,uri"]',
+                '["drush", "status", "-vvv", "--fields=root,uri"]',
                 [],
                 ['drush', 'status'],
-                ['fields' => 'root,uri'],
+                ['vvv' => '-short', 'fields' => 'root,uri'],
                 [],
             ],