PSR12/OpenTag: improve performance

No functional changes at all, just improving performance of the sniff by changing the order of certain checks.

Some benchmarks for this change run using the Performance report (PR 3810):

Command: `phpcs -ps . --extensions=php --ignore=/vendor/ --report=performance --standard=psr12`

Output for the `PSR12.Files.OpenTag` sniff:

Result | PHPCS itself       | Set of Projects A  | Set of Projects B  | Set of Projects C |
------ | ------------------ | ------------------ | ------------------ | ----------------- |
Nr of Files Scanned | 614   | 4115               | 25546              | 2250              |
Before | 0.077045 (  2.3 %) | 0.982014 (  1.9 %) | 3.267655 (  2.1 %) | 0.179564 (  2.1 %)
After  | 0.000928 (  0.0 %) | 0.013066 (  0.0 %) | 0.091816 (  0.1 %) | 0.109021 (  1.3 %)

With what the sniff does, the impact is biggest for files/codebases which already comply with the expectations of this sniff.

CHANGELOG.md

@@ -101,6 +101,8 @@ The file documents changes to the PHP_CodeSniffer project.
     - Thanks to Juliette Reinders Folmer (@jrfnl) for the patch
 - The following sniffs have received performance related improvements:
     - Generic.PHP.LowerCaseType
+    - PSR12.Files.OpenTag
+    - Thanks to Juliette Reinders Folmer (@jrfnl) for the patches
 - The -e (explain) command will now list sniffs in natural order
     - Thanks to Juliette Reinders Folmer (@jrfnl) for the patch
 - Tests using the PHPCS native test framework with multiple test case files will now run the test case files in numeric order.

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

@@ -44,25 +44,28 @@ public function process(File $phpcsFile, $stackPtr)
             return $phpcsFile->numTokens;
         }
 
-        $next = $phpcsFile->findNext(T_INLINE_HTML, 0);
-        if ($next !== false) {
-            // This rule only applies to PHP-only files.
-            return $phpcsFile->numTokens;
-        }
-
         $tokens = $phpcsFile->getTokens();
         $next   = $phpcsFile->findNext(T_WHITESPACE, ($stackPtr + 1), null, true);
         if ($next === false) {
             // Empty file.
             return $phpcsFile->numTokens;
         }
 
-        if ($tokens[$next]['line'] === $tokens[$stackPtr]['line']) {
-            $error = 'Opening PHP tag must be on a line by itself';
-            $fix   = $phpcsFile->addFixableError($error, $stackPtr, 'NotAlone');
-            if ($fix === true) {
-                $phpcsFile->fixer->addNewline($stackPtr);
-            }
+        if ($tokens[$next]['line'] !== $tokens[$stackPtr]['line']) {
+            // Tag is on a line by itself.
+            return $phpcsFile->numTokens;
+        }
+
+        $next = $phpcsFile->findNext(T_INLINE_HTML, 0);
+        if ($next !== false) {
+            // This rule only applies to PHP-only files.
+            return $phpcsFile->numTokens;
+        }
+
+        $error = 'Opening PHP tag must be on a line by itself';
+        $fix   = $phpcsFile->addFixableError($error, $stackPtr, 'NotAlone');
+        if ($fix === true) {
+            $phpcsFile->fixer->addNewline($stackPtr);
         }
 
         return $phpcsFile->numTokens;