symfony
diff --git a/‎src/Symfony/Component/Finder/Gitignore.php
Lines changed: 43 additions & 88 deletions b/‎src/Symfony/Component/Finder/Gitignore.php
Lines changed: 43 additions & 88 deletions
@@ -15,119 +15,74 @@
  * Gitignore matches against text.
  *
  * @author Ahmed Abdou <[email protected]>
+ * @author Michael Voříšek <[email protected]>
  */
 class Gitignore
 {
     /**
      * Returns a regexp which is the equivalent of the gitignore pattern.
      *
+     * Format specification: https://git-scm.com/docs/gitignore#_pattern_format
+     *
      * @return string The regexp
      */
     public static function toRegex(string $gitignoreFileContent): string
     {
-        $gitignoreFileContent = preg_replace('/^[^\\\r\n]*#.*/m', '', $gitignoreFileContent);
-        $gitignoreLines = preg_split('/\r\n|\r|\n/', $gitignoreFileContent);
+        $gitignoreFileContent = preg_replace('~(?<!\\\\)#[^\n\r]*~', '', $gitignoreFileContent);
+        $gitignoreLines = preg_split('~\r\n?|\n~', $gitignoreFileContent);
 
-        $positives = [];
-        $negatives = [];
+        $res = self::lineToRegex('');
         foreach ($gitignoreLines as $i => $line) {
-            $line = trim($line);
-            if ('' === $line) {
-                continue;
+            if (\strlen($line) < 2 || '\\' !== substr($line, -2, 1)) {
+                $line = rtrim($line);
             }
 
-            if (1 === preg_match('/^!/', $line)) {
-                $positives[$i] = null;
-                $negatives[$i] = self::getRegexFromGitignore(preg_replace('/^!(.*)/', '${1}', $line), true);
-
-                continue;
+            if (0 === strpos($line, '!')) {
+                $line = substr($line, 1);
+                if ('' !== $line) {
+                    $res = '(?!'.self::lineToRegex($line).')'.$res;
+                }
+            } elseif ('' !== $line) {
+                $res = '(?:'.$res.'|'.self::lineToRegex($line).')';
             }
-            $negatives[$i] = null;
-            $positives[$i] = self::getRegexFromGitignore($line);
         }
 
-        $index = 0;
-        $patterns = [];
-        foreach ($positives as $pattern) {
-            if (null === $pattern) {
-                continue;
-            }
-
-            $negativesAfter = array_filter(\array_slice($negatives, ++$index));
-            if ([] !== $negativesAfter) {
-                $pattern .= sprintf('(?<!%s)', implode('|', $negativesAfter));
-            }
-
-            $patterns[] = $pattern;
-        }
-
-        return sprintf('/^((%s))$/', implode(')|(', $patterns));
+        return '~^(?:'.$res.')~s';
     }
 
-    private static function getRegexFromGitignore(string $gitignorePattern, bool $negative = false): string
+    private static function lineToRegex(string $gitignoreLine): string
     {
-        $regex = '';
-        $isRelativePath = false;
-        // If there is a separator at the beginning or middle (or both) of the pattern, then the pattern is relative to the directory level of the particular .gitignore file itself
-        $slashPosition = strpos($gitignorePattern, '/');
-        if (false !== $slashPosition && \strlen($gitignorePattern) - 1 !== $slashPosition) {
-            if (0 === $slashPosition) {
-                $gitignorePattern = substr($gitignorePattern, 1);
-            }
-
-            $isRelativePath = true;
-            $regex .= '^';
-        }
-
-        if ('/' === $gitignorePattern[\strlen($gitignorePattern) - 1]) {
-            $gitignorePattern = substr($gitignorePattern, 0, -1);
+        if ('' === $gitignoreLine) {
+            return '$f'; // always false
         }
 
-        $iMax = \strlen($gitignorePattern);
-        for ($i = 0; $i < $iMax; ++$i) {
-            $tripleChars = substr($gitignorePattern, $i, 3);
-            if ('**/' === $tripleChars || '/**' === $tripleChars) {
-                $regex .= '.*';
-                $i += 2;
-                continue;
-            }
-
-            $doubleChars = substr($gitignorePattern, $i, 2);
-            if ('**' === $doubleChars) {
-                $regex .= '.*';
-                ++$i;
-                continue;
+        $slashPos = strpos($gitignoreLine, '/');
+        if (false !== $slashPos && \strlen($gitignoreLine) - 1 !== $slashPos) {
+            if (0 === $slashPos) {
+                $gitignoreLine = substr($gitignoreLine, 1);
             }
-            if ('*/' === $doubleChars) {
-                $regex .= '[^\/]*\/?[^\/]*';
-                ++$i;
-                continue;
-            }
-
-            $c = $gitignorePattern[$i];
-            switch ($c) {
-                case '*':
-                    $regex .= $isRelativePath ? '[^\/]*' : '[^\/]*\/?[^\/]*';
-                    break;
-                case '/':
-                case '.':
-                case ':':
-                case '(':
-                case ')':
-                case '{':
-                case '}':
-                    $regex .= '\\'.$c;
-                    break;
-                default:
-                    $regex .= $c;
-            }
-        }
 
-        if ($negative) {
-            // a lookbehind assertion has to be a fixed width (it can not have nested '|' statements)
-            return sprintf('%s$|%s\/$', $regex, $regex);
+            $isAbsolute = true;
+        } else {
+            $isAbsolute = false;
         }
 
-        return '(?>'.$regex.'($|\/.*))';
+        $parts = array_map(function (string $v): string {
+            $v = preg_quote(str_replace('\\', '', $v), '~');
+            $v = preg_replace_callback('~\\\\\[([^\[\]]*)\\\\\]~', function (array $matches): string {
+                return '['.str_replace('\\-', '-', $matches[1]).']';
+            }, $v);
+            $v = preg_replace('~\\\\\*\\\\\*~', '[^/]+(?:/[^/]+)*', $v);
+            $v = preg_replace('~\\\\\*~', '[^/]*', $v);
+            $v = preg_replace('~\\\\\?~', '[^/]', $v);
+
+            return $v;
+        }, explode('/', $gitignoreLine));
+
+        return '(?:'
+            .($isAbsolute ? '' : '(?:[^/]+/)*')
+            .implode('/', $parts)
+            .('' !== end($parts) ? '(?:$|/)' : '')
+            .')';
     }
 }