Correct Xlsx Parsing of quotePrefix="0"

src/PhpSpreadsheet/Reader/Xlsx.php

@@ -618,7 +618,7 @@ protected function loadSpreadsheetFromFile(string $filename): Spreadsheet
                                     $numFmt = NumberFormat::builtInFormatCode((int) $xf['numFmtId']);
                                 }
                             }
-                            $quotePrefix = (bool) ($xf['quotePrefix'] ?? false);
+                            $quotePrefix = (bool) (string) ($xf['quotePrefix'] ?? '');
 
                             $style = (object) [
                                 'numFmt' => $numFmt ?? NumberFormat::FORMAT_GENERAL,
@@ -653,7 +653,7 @@ protected function loadSpreadsheetFromFile(string $filename): Spreadsheet
                                 }
                             }
 
-                            $quotePrefix = (bool) ($xf['quotePrefix'] ?? false);
+                            $quotePrefix = (bool) (string) ($xf['quotePrefix'] ?? '');
 
                             $cellStyle = (object) [
                                 'numFmt' => $numFmt,

tests/PhpSpreadsheetTests/Reader/Xlsx/Issue3435Test.php

@@ -0,0 +1,44 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheetTests\Reader\Xlsx;
+
+use PhpOffice\PhpSpreadsheet\Reader\Xlsx;
+
+class Issue3435Test extends \PHPUnit\Framework\TestCase
+{
+    /**
+     * @var string
+     */
+    private static $testbook = 'tests/data/Reader/XLSX/issue.3435.xlsx';
+
+    public function testPreliminaries(): void
+    {
+        $file = 'zip://';
+        $file .= self::$testbook;
+        $file .= '#xl/styles.xml';
+        $data = file_get_contents($file);
+        // confirm that file contains expected namespaced xml tag
+        if ($data === false) {
+            self::fail('Unable to read file');
+        } else {
+            $expected = <<<EOF
+                <xf numFmtId="0" fontId="0" fillId="0" borderId="0" xfId="0"/>
+                <xf numFmtId="0" fontId="0" fillId="0" borderId="0" xfId="0" quotePrefix="1"/>
+                <xf numFmtId="0" fontId="1" fillId="2" borderId="1" xfId="0" quotePrefix="0" applyFont="1" applyFill="1" applyBorder="1"/>
+                EOF;
+            self::assertStringContainsString($expected, $data);
+        }
+    }
+
+    public function testQuotePrefix(): void
+    {
+        // Parsing of quotePrefix="0" was incorrect, now corrected.
+        $reader = new Xlsx();
+        $spreadsheet = $reader->load(self::$testbook);
+        $sheet = $spreadsheet->getActiveSheet();
+        self::assertTrue($sheet->getStyle('A1')->getQuotePrefix());
+        self::assertFalse($sheet->getStyle('A2')->getQuotePrefix());
+        self::assertFalse($sheet->getStyle('A3')->getQuotePrefix());
+        $spreadsheet->disconnectWorksheets();
+    }
+}