Common::getSniffCode(): throw exception on invalid input [1]

Previously, if an empty string was passed, the `Common::getSniffCode()` method would return `..`, which is just confusing (and incorrect).

This commit changes the behaviour to throw an `InvalidArgumentException` instead.

Includes making a potentially superfluous function call to the method conditionally (as it could hit the new exception).

Includes test.

Author: jrfnl

src/Files/File.php

@@ -873,9 +873,13 @@ protected function addMessage($error, $message, $line, $column, $code, $data, $s
         $parts = explode('.', $code);
         if ($parts[0] === 'Internal') {
             // An internal message.
-            $listenerCode = Common::getSniffCode($this->activeListener);
-            $sniffCode    = $code;
-            $checkCodes   = [$sniffCode];
+            $listenerCode = '';
+            if ($this->activeListener !== '') {
+                $listenerCode = Common::getSniffCode($this->activeListener);
+            }
+
+            $sniffCode  = $code;
+            $checkCodes = [$sniffCode];
         } else {
             if ($parts[0] !== $code) {
                 // The full message code has been passed in.

src/Util/Common.php

@@ -9,6 +9,7 @@
 
 namespace PHP_CodeSniffer\Util;
 
+use InvalidArgumentException;
 use Phar;
 
 class Common
@@ -529,9 +530,15 @@ public static function suggestType($varType)
      * @param string $sniffClass The fully qualified sniff class name.
      *
      * @return string
+     *
+     * @throws \InvalidArgumentException When $sniffClass is not a non-empty string.
      */
     public static function getSniffCode($sniffClass)
     {
+        if (is_string($sniffClass) === false || $sniffClass === '') {
+            throw new InvalidArgumentException('The $sniffClass parameter must be a non-empty string');
+        }
+
         $parts = explode('\\', $sniffClass);
         $sniff = array_pop($parts);
 

tests/Core/Util/Common/GetSniffCodeTest.php

@@ -21,6 +21,51 @@ final class GetSniffCodeTest extends TestCase
 {
 
 
+    /**
+     * Test receiving an expected exception when the $sniffClass parameter is not passed a string value or is passed an empty string.
+     *
+     * @param string $input NOT a fully qualified sniff class name.
+     *
+     * @dataProvider dataGetSniffCodeThrowsExceptionOnInvalidInput
+     *
+     * @return void
+     */
+    public function testGetSniffCodeThrowsExceptionOnInvalidInput($input)
+    {
+        $exception = 'InvalidArgumentException';
+        $message   = 'The $sniffClass parameter must be a non-empty string';
+
+        if (method_exists($this, 'expectException') === true) {
+            // PHPUnit 5+.
+            $this->expectException($exception);
+            $this->expectExceptionMessage($message);
+        } else {
+            // PHPUnit 4.
+            $this->setExpectedException($exception, $message);
+        }
+
+        Common::getSniffCode($input);
+
+    }//end testGetSniffCodeThrowsExceptionOnInvalidInput()
+
+
+    /**
+     * Data provider.
+     *
+     * @see testGetSniffCodeThrowsExceptionOnInvalidInput()
+     *
+     * @return array<string, array<string>>
+     */
+    public static function dataGetSniffCodeThrowsExceptionOnInvalidInput()
+    {
+        return [
+            'Class name is not a string' => [true],
+            'Class name is empty'        => [''],
+        ];
+
+    }//end dataGetSniffCodeThrowsExceptionOnInvalidInput()
+
+
     /**
      * Test transforming a sniff class name to a sniff code.
      *