YAML handler bug-fix (CIDRAM/CIDRAM#532).

Changelog excerpt: - The YAML handler's unescape method wasn't unescaping correctly when escaped backslashes preceded other escapable symbols; Fixed.
Maikuolan · Nov 21, 2023 · 75bed39 · 75bed39
1 parent e619471
commit 75bed39
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diff --git a/Changelog.txt b/Changelog.txt
@@ -16,7 +16,11 @@ found at:
   codebases, as well as to the code for the DocGen scripts at both those
   projects' documentation repositories, has been integrated to the L10N
   handler, so that it can be removed from those codebases, and can instead be
-  called from the L10N handler, for cleaner/easier maintainability).
+  called from the L10N handler, for cleaner/easier maintainability.
+
+- [2023.11.21; Bug-fix; Maikuolan]: The YAML handler's unescape method wasn't
+  unescaping correctly when escaped backslashes preceded other escapable
+  symbols; Fixed (CIDRAM/CIDRAM#532).
 
 === Version/Release 1.9.8 ===
 PATCH RELEASE.

diff --git a/src/YAML.php b/src/YAML.php
@@ -1,6 +1,6 @@
 <?php
 /**
- * YAML handler (last modified: 2023.10.12).
+ * YAML handler (last modified: 2023.11.21).
  *
  * This file is a part of the "common classes package", utilised by a number of
  * packages and projects, including CIDRAM and phpMussel.
@@ -901,52 +901,46 @@ private function escape($Value = '', $Newlines = true)
     private function unescape($Value = '', $Style = '"')
     {
         if ($Style === '"' || $Style === "\xe2\x80\x9c" || $Style === "\x91") {
-            $Value = str_replace(
-                ['\#', '\0', '\a', '\b', '\t', '\n', '\v', '\f', '\r', '\e', '\"', '\/', '\N', '\_', '\L', '\P', "\\\\"],
-                ['#', "\0", "\x07", "\x08", "\t", "\n", "\x0B", "\x0C", "\x0D", "\x1B", '"', '/', "\xC2\x85", "\xC2\xA0", "\xE2\x80\xA8", "\xE2\x80\xA9", "\\"],
-                $Value
-            );
-            $Captured = [];
-            if (preg_match_all('~\\\\x([\dA-Fa-f]{2})~', $Value, $Captured)) {
-                $Captured = array_unique($Captured[1]);
-                foreach ($Captured as $Bytes) {
-                    $Value = str_replace('\\x' . $Bytes, hex2bin($Bytes), $Value);
-                }
-            }
-            $Captured = [];
-            if (preg_match_all('~\\\\u([\dA-Fa-f]{4})~', $Value, $Captured)) {
-                set_error_handler(function ($errno) {
-                    return;
-                });
-                $Captured = array_unique($Captured[1]);
-                foreach ($Captured as $Bytes) {
-                    $Decoded = hex2bin($Bytes);
-                    $Attempt = iconv('UTF-16BE', 'UTF-8', $Decoded);
-                    $Reversed = $Attempt === false ? '' : iconv('UTF-8', 'UTF-16BE', $Attempt);
-                    if ($Attempt !== false && strcmp($Reversed, $Decoded) === 0) {
-                        $Decoded = $Attempt;
-                    }
-                    $Value = str_replace('\\u' . $Bytes, $Decoded, $Value);
+            set_error_handler(function ($errno) {
+                return;
+            });
+            $Value = preg_replace([
+                '~(?<!\\\\)\\\\((?:\\\\{2})*)#~',
+                '~(?<!\\\\)\\\\((?:\\\\{2})*)0~',
+                '~(?<!\\\\)\\\\((?:\\\\{2})*)a~',
+                '~(?<!\\\\)\\\\((?:\\\\{2})*)b~',
+                '~(?<!\\\\)\\\\((?:\\\\{2})*)t~',
+                '~(?<!\\\\)\\\\((?:\\\\{2})*)n~',
+                '~(?<!\\\\)\\\\((?:\\\\{2})*)v~',
+                '~(?<!\\\\)\\\\((?:\\\\{2})*)f~',
+                '~(?<!\\\\)\\\\((?:\\\\{2})*)r~',
+                '~(?<!\\\\)\\\\((?:\\\\{2})*)e~',
+                '~(?<!\\\\)\\\\((?:\\\\{2})*)"~',
+                '~(?<!\\\\)\\\\((?:\\\\{2})*)/~',
+                '~(?<!\\\\)\\\\((?:\\\\{2})*)N~',
+                '~(?<!\\\\)\\\\((?:\\\\{2})*)_~',
+                '~(?<!\\\\)\\\\((?:\\\\{2})*)L~',
+                '~(?<!\\\\)\\\\((?:\\\\{2})*)P~'
+            ], ['#', "\0", "\7", "\x08", "\t", "\n", "\x0B", "\x0C", "\x0D", "\x1B", '"', '/', "\xC2\x85", "\xC2\xA0", "\xE2\x80\xA8", "\xE2\x80\xA9"], $Value);
+            $Value = preg_replace_callback('~(?<!\\\\)\\\\((?:\\\\{2})*)x([\dA-Fa-f]{2})~', function($Captured) {
+                return ($Decoded = hex2bin($Captured[2])) === false ? $Captured[0] : $Captured[1] . $Decoded;
+            }, $Value);
+            $Value = preg_replace_callback('~(?<!\\\\)\\\\((?:\\\\{2})*)u([\dA-Fa-f]{4})~', function($Captured) {
+                if (($Decoded = hex2bin($Captured[2])) === false) {
+                    return $Captured[0];
                 }
-                restore_error_handler();
-            }
-            $Captured = [];
-            if (preg_match_all('~\\\\U([\dA-Fa-f]{8})~', $Value, $Captured)) {
-                set_error_handler(function ($errno) {
-                    return;
-                });
-                $Captured = array_unique($Captured[1]);
-                foreach ($Captured as $Bytes) {
-                    $Decoded = hex2bin($Bytes);
-                    $Attempt = iconv('UTF-32BE', 'UTF-8', $Decoded);
-                    $Reversed = $Attempt === false ? '' : iconv('UTF-8', 'UTF-32BE', $Attempt);
-                    if ($Attempt !== false && strcmp($Reversed, $Decoded) === 0) {
-                        $Decoded = $Attempt;
-                    }
-                    $Value = str_replace('\\U' . $Bytes, $Decoded, $Value);
+                $Reversed = ($Attempt = iconv('UTF-16BE', 'UTF-8', $Decoded)) === false ? '' : iconv('UTF-8', 'UTF-16BE', $Attempt);
+                return $Captured[1] . (($Attempt !== false && strcmp($Reversed, $Decoded) === 0) ? $Attempt : $Decoded);
+            }, $Value);
+            $Value = preg_replace_callback('~(?<!\\\\)\\\\((?:\\\\{2})*)U([\dA-Fa-f]{8})~', function($Captured) {
+                if (($Decoded = hex2bin($Captured[2])) === false) {
+                    return $Captured[0];
                 }
-                restore_error_handler();
-            }
+                $Reversed = ($Attempt = iconv('UTF-32BE', 'UTF-8', $Decoded)) === false ? '' : iconv('UTF-8', 'UTF-32BE', $Attempt);
+                return $Captured[1] . (($Attempt !== false && strcmp($Reversed, $Decoded) === 0) ? $Attempt : $Decoded);
+            }, $Value);
+            $Value = str_replace('\\\\', '\\', $Value);
+            restore_error_handler();
             return $Value;
         }
         if ($Style === "'" || $Style === "\xe2\x80\x98" || $Style === "\x93") {