formula backslash escaping

application/Espo/Core/Formula/Functions/ValueType.php

@@ -30,7 +30,6 @@
 namespace Espo\Core\Formula\Functions;
 
 use Espo\Core\Formula\Exceptions\Error;
-
 use Espo\Core\Formula\ArgumentList;
 
 class ValueType extends BaseFunction
@@ -41,12 +40,6 @@ class ValueType extends BaseFunction
             throw new Error("Bad value.");
         }
 
-        $value = $args[0]->getData();
-
-        if (is_string($value)) {
-            $value = str_replace("\\n", "\n", $value);
-        }
-
-        return $value;
+        return $args[0]->getData();
     }
 }

application/Espo/Core/Formula/Parser.php

@@ -1002,10 +1002,7 @@ class Parser
             $expression[0] === "'" && $expression[strlen($expression) - 1] === "'" ||
             $expression[0] === "\"" && $expression[strlen($expression) - 1] === "\""
         ) {
-            $subExpression = substr($expression, 1, strlen($expression) - 2);
-            $subExpression = str_replace(["\\\\", "\\\""], ["\\", "\""], $subExpression);
-
-            return new Value($subExpression);
+            return new Value(self::stripStringSlashes($expression));
         }
 
         if ($expression[0] === "$") {
@@ -1290,4 +1287,58 @@ class Parser
 
         return $argumentList;
     }
+
+    static private function stripStringSlashes(string $expression): string
+    {
+        $string = substr($expression, 1, strlen($expression) - 2);
+
+        /** @var array{bool, string}[] $tokens */
+        $tokens = [];
+
+        $stripList = ["\\\\", "\\\"", "\\n", "\\t", "\\r"];
+        $replaceList = ["\\",  "\"", "\n", "\t", "\r"];
+
+        $k = 0;
+
+        for ($i = 0; $i < strlen($string); $i++) {
+            $part = substr($string, $i, 2);
+
+            if (in_array($part, $stripList)) {
+                $len = strlen($part);
+
+                $before = substr($string, $k, $i - $k);
+
+                if (strlen($before)) {
+                    $tokens[] = [false, $before];
+                }
+
+                $tokens[] = [true, $part];
+
+                $i += $len - 1;
+                $k = $i + 1;
+            }
+
+            if ($i >= strlen($string) - 1) {
+                $after = substr($string, $k);
+
+                if (strlen($after)) {
+                    $tokens[] = [false, $after];
+                }
+            }
+        }
+
+        $result = '';
+
+        foreach ($tokens as $token) {
+            if (!$token[0]) {
+                $result .= $token[1];
+
+                continue;
+            }
+
+            $result .= str_replace($stripList, $replaceList, $token[1]);
+        }
+
+        return $result;
+    }
 }

tests/unit/Espo/Core/Formula/EvaluatorTest.php

@@ -1449,4 +1449,54 @@ class EvaluatorTest extends \PHPUnit\Framework\TestCase
 
         $this->assertEquals("\"", $result);
     }
+
+    public function testStrings3(): void
+    {
+        $expression = '"\\n"';
+
+        /** @noinspection PhpUnhandledExceptionInspection */
+        $result = $this->evaluator->process($expression);
+
+        $this->assertEquals("\n", $result);
+    }
+
+    public function testStrings4(): void
+    {
+        $expression = '"\\\\n"';
+
+        /** @noinspection PhpUnhandledExceptionInspection */
+        $result = $this->evaluator->process($expression);
+
+        $this->assertEquals("\\n", $result);
+    }
+
+    public function testStrings5(): void
+    {
+        $expression = '"test\\\\nest\\\\nest"';
+
+        /** @noinspection PhpUnhandledExceptionInspection */
+        $result = $this->evaluator->process($expression);
+
+        $this->assertEquals("test\\nest\\nest", $result);
+    }
+
+    public function testStrings6(): void
+    {
+        $expression = '"\\n\\\\test"';
+
+        /** @noinspection PhpUnhandledExceptionInspection */
+        $result = $this->evaluator->process($expression);
+
+        $this->assertEquals("\n\\test", $result);
+    }
+
+    public function testStrings7(): void
+    {
+        $expression = '"\\n\\\\test\\n"';
+
+        /** @noinspection PhpUnhandledExceptionInspection */
+        $result = $this->evaluator->process($expression);
+
+        $this->assertEquals("\n\\test\n", $result);
+    }
 }