[FEATURE] Do not escape characters that do not need escaping in CSS string

Author: 8ctopus

CHANGELOG.md

@@ -39,6 +39,12 @@ Please also have a look at our
 
 ### Documentation
 
+## 9.2.0:
+
+### Fixed
+
+- Do not escape characters that do not need escaping in CSS string (#1444)
+
 ## 9.1.0: Add support for PHP 8.5
 
 ### Added

src/Value/CSSString.php

@@ -93,7 +93,7 @@ public function getString(): string
      */
     public function render(OutputFormat $outputFormat): string
     {
-        $string = \addslashes($this->string);
+        $string = $this->escape($this->string, $outputFormat->getStringQuotingType());
         $string = \str_replace("\n", '\\A', $string);
         return $outputFormat->getStringQuotingType() . $string . $outputFormat->getStringQuotingType();
     }
@@ -111,4 +111,13 @@ public function getArrayRepresentation(): array
             'contents' => $this->string,
         ];
     }
+
+    private function escape(string $str, string $quote) : string
+    {
+        $str = \addslashes($str);
+
+        $replace = $quote === '"' ? ["\\'" => "'"] : ["\\\"" => "\""];
+
+        return \str_replace(array_keys($replace), array_values($replace), $str);
+    }
 }

tests/ParserTest.php

@@ -206,10 +206,10 @@ public function unicodeParsing(): void
                 self::assertSame('"\\"\\""', $firstContentRuleAsString);
             }
             if ($selector === '.test-9') {
-                self::assertSame('"\\"\\\'"', $firstContentRuleAsString);
+                self::assertSame('"\\"\'"', $firstContentRuleAsString);
             }
             if ($selector === '.test-10') {
-                self::assertSame('"\\\'\\\\"', $firstContentRuleAsString);
+                self::assertSame('"\'\\\\"', $firstContentRuleAsString);
             }
             if ($selector === '.test-11') {
                 self::assertSame('"test"', $firstContentRuleAsString);

tests/fixtures/unicode.css

@@ -5,7 +5,7 @@
 .test-6 { content: "\00A5" } /* Same as "¥" */
 .test-7 { content: '\a' } /* Same as "\A" (Newline) */
 .test-8 { content: "\"\22" } /* Same as "\"\"" */
-.test-9 { content: "\"\27" } /* Same as ""\"\'"" */
+.test-9 { content: "\"\27" } /* Same as ""\"'"" */
 .test-10 { content: "\'\\" } /* Same as "'\" */
 .test-11 { content: "\test" } /* Same as "test" */