Fixed detection of file-level docblocks (ref #750)

Code wasn't taking prefixes into account when determining if the docblock belong to a scope opener

package.xml

@@ -1200,6 +1200,7 @@ http://pear.php.net/dtd/package-2.0.xsd">
         <file baseinstalldir="PHP/CodeSniffer" name="FileHeaderUnitTest.4.inc" role="test" />
         <file baseinstalldir="PHP/CodeSniffer" name="FileHeaderUnitTest.4.inc.fixed" role="test" />
         <file baseinstalldir="PHP/CodeSniffer" name="FileHeaderUnitTest.5.inc" role="test" />
+        <file baseinstalldir="PHP/CodeSniffer" name="FileHeaderUnitTest.6.inc" role="test" />
         <file baseinstalldir="PHP/CodeSniffer" name="FileHeaderUnitTest.php" role="test" />
         <file baseinstalldir="PHP/CodeSniffer" name="ImportStatementUnitTest.inc" role="test" />
         <file baseinstalldir="PHP/CodeSniffer" name="ImportStatementUnitTest.php" role="test" />

src/Standards/PSR12/Sniffs/Files/FileHeaderSniff.php

@@ -72,7 +72,9 @@ public function process(File $phpcsFile, $stackPtr)
                 // Make sure this is not a code-level docblock.
                 $end      = $tokens[$next]['comment_closer'];
                 $docToken = $phpcsFile->findNext(Tokens::$emptyTokens, ($end + 1), null, true);
-                if (isset(Tokens::$scopeOpeners[$tokens[$docToken]['code']]) === false) {
+                if (isset(Tokens::$scopeOpeners[$tokens[$docToken]['code']]) === false
+                    && isset(Tokens::$methodPrefixes[$tokens[$docToken]['code']]) === false
+                ) {
                     $foundDocblock = true;
                     $headerLines[] = [
                         'type'  => 'docblock',

src/Standards/PSR12/Tests/Files/FileHeaderUnitTest.6.inc

@@ -0,0 +1,13 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Controller;
+
+/**
+ * This is a class docblock, not a file docblock.
+ */
+final class MyController
+{
+
+}