Use hex escaping for special characters in strings

Apart from \0, using the \xHH notation is more typical.
nikic · Apr 25, 2021 · 6b409b9 · 6b409b9
1 parent f68e1a4
commit 6b409b9
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diff --git a/lib/PhpParser/PrettyPrinter/Standard.php b/lib/PhpParser/PrettyPrinter/Standard.php
@@ -999,13 +999,9 @@ protected function escapeString($string, $quote) {
         }
 
         // Escape other control characters
-        return preg_replace_callback('/([\0-\10\16-\37])(?=([0-7]?))/', function ($matches) {
-            $oct = decoct(ord($matches[1]));
-            if ($matches[2] !== '') {
-                // If there is a trailing digit, use the full three character form
-                return '\\' . str_pad($oct, 3, '0', \STR_PAD_LEFT);
-            }
-            return '\\' . $oct;
+        return preg_replace_callback('/[\x00-\x08\x0e-\x1f]/', function ($matches) {
+            $hex = dechex(ord($matches[0]));;
+            return '\\x' . str_pad($hex, 2, '0', \STR_PAD_LEFT);
         }, $escaped);
     }
 

diff --git a/test/code/prettyPrinter/expr/stringEscaping.test b/test/code/prettyPrinter/expr/stringEscaping.test
@@ -15,13 +15,13 @@ DOC;
 
 -----
 "\n\r\t\f\v\$\"\\";
-"\0\1\2\3\4\5\6\7\10\t\n\v\f\r\16\17\20\21\22\23\24\25\26\27\30\31\32\33\34\35\36\37";
-"\0000\0001";
+"\x00\x01\x02\x03\x04\x05\x06\x07\x08\t\n\v\f\r\x0e\x0f\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f";
+"\x000\x001";
 "äöü";
 <<<DOC
 @@{ "\n\r" }@@\t\f\v\$\\"\\
-\0\1\2\3\4\5\6\7\10\t@@{ "\n" }@@\v\f@@{ "\r" }@@\16\17\20\21\22\23\24\25\26\27\30\31\32\33\34\35\36\37
-\0000\0001
+\x00\x01\x02\x03\x04\x05\x06\x07\x08\t@@{ "\n" }@@\v\f@@{ "\r" }@@\x0e\x0f\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f
+\x000\x001
 äöü
 DOC
 ;