Read Spreadsheet with # in Name (#2409)

Fix #2405. Treat last, rather than first, `#` as separator between zip file name and member name, by finding it with strrpos rather than strpos.

src/PhpSpreadsheet/Shared/File.php

@@ -56,8 +56,8 @@ public static function fileExists(string $filename): bool
         // doing the original file_exists on ZIP archives...
         if (strtolower(substr($filename, 0, 6)) == 'zip://') {
             // Open ZIP file and verify if the file exists
-            $zipFile = substr($filename, 6, strpos($filename, '#') - 6);
-            $archiveFile = substr($filename, strpos($filename, '#') + 1);
+            $zipFile = substr($filename, 6, strrpos($filename, '#') - 6);
+            $archiveFile = substr($filename, strrpos($filename, '#') + 1);
 
             if (self::validateZipFirst4($zipFile)) {
                 $zip = new ZipArchive();

tests/PhpSpreadsheetTests/Reader/Xlsx/OctothorpeTest.php

@@ -0,0 +1,20 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheetTests\Reader\Xlsx;
+
+use PhpOffice\PhpSpreadsheet\IOFactory;
+use PHPUnit\Framework\TestCase;
+
+class OctothorpeTest extends TestCase
+{
+    public function testOctothorpeInName(): void
+    {
+        // Permit # in file name.
+        $filename = 'tests/data/Reader/XLSX/octo#thorpe.xlsx';
+        $reader = IOFactory::createReader('Xlsx');
+        $spreadsheet = $reader->load($filename);
+        $sheet = $spreadsheet->getActiveSheet();
+        self::assertSame('xyz', $sheet->getCell('A1')->getValue());
+        $spreadsheet->disconnectWorksheets();
+    }
+}