Using htmlspecialchars to fix issue #3145 (#3146)

* Using htmlspecialchars to fix issue #3145: this prevents the SimpleXMLElement error "unterminated entity reference" when HTML entities are present in a worksheet

* replace htmlspecialchars with proposal of oleibman

* eliminate string cast, because PhpStan has a problem with that

* ignore string cast for phpstan + enhance unit test

src/PhpSpreadsheet/Reader/Xlsx.php

@@ -940,7 +940,10 @@ protected function loadSpreadsheetFromFile(string $filename): Spreadsheet
                                     }
                                     $node->addAttribute('sqref', $item->children(Namespaces::DATA_VALIDATIONS2)->sqref);
                                     if (isset($item->formula1)) {
-                                        $node->addChild('formula1', $item->formula1->children(Namespaces::DATA_VALIDATIONS2)->f);
+                                        $childNode = $node->addChild('formula1');
+                                        if ($childNode !== null) { // null should never happen
+                                            $childNode[0] = (string) $item->formula1->children(Namespaces::DATA_VALIDATIONS2)->f; // @phpstan-ignore-line
+                                        }
                                     }
                                 }
                             }

tests/PhpSpreadsheetTests/Reader/Xlsx/Issue3145Test.php

@@ -0,0 +1,23 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheetTests\Reader\Xlsx;
+
+use PhpOffice\PhpSpreadsheet\IOFactory;
+use PHPUnit\Framework\TestCase;
+
+class Issue3145Test extends TestCase
+{
+    public function testIssue3145(): void
+    {
+        $filename = 'tests/data/Reader/XLSX/issue.3145.xlsx';
+        $reader = IOFactory::createReader('Xlsx');
+        $spreadsheet = $reader->load($filename);
+        $sheet = $spreadsheet->getActiveSheet();
+
+        self::assertEquals('Headline A', $sheet->getCell('A1')->getValue());
+        self::assertEquals('Configdential B', $sheet->getCell('A2')->getValue());
+        self::assertSame('OFFSET(INDIRECT(SUBSTITUTE($A2," ","")),0,0,COUNTA(INDIRECT(SUBSTITUTE($A2," ","")&"Col")),1)', $sheet->getCell('B2')->getDataValidation()->getFormula1());
+
+        $spreadsheet->disconnectWorksheets();
+    }
+}