Bug in Uncovered Code in XMLWriter

Add test, fix bug.

Author: oleibman

src/PhpSpreadsheet/Shared/XMLWriter.php

@@ -39,6 +39,7 @@ public function __construct(int $temporaryStorage = self::STORAGE_MEMORY, ?strin
             if (empty($this->tempFileName) || $this->openUri($this->tempFileName) === false) {
                 // Fallback to memory...
                 $this->openMemory();
+                $this->tempFileName = '';
             }
         }
 

tests/PhpSpreadsheetTests/Shared/XMLWriterNoUri.php

@@ -0,0 +1,13 @@
+<?php
+
+declare(strict_types=1);
+
+namespace PhpOffice\PhpSpreadsheetTests\Shared;
+
+class XMLWriterNoUri extends \PhpOffice\PhpSpreadsheet\Shared\XMLWriter
+{
+    public function openUri(string $uri): bool
+    {
+        return false;
+    }
+}

tests/PhpSpreadsheetTests/Shared/XmlWriterTest.php

@@ -83,4 +83,28 @@ public function testDiskCache(): void
         $expected .= '</root>' . $indentnl;
         self::assertSame($expected, $objWriter->getData());
     }
+
+    public function testFallbackToMemory(): void
+    {
+        XMLWriter::$debugEnabled = false;
+        $indent = '';
+        $indentnl = '';
+        $objWriter = new XMLWriterNoUri(XMLWriter::STORAGE_DISK);
+        $objWriter->startDocument('1.0', 'UTF-8', 'yes');
+        $expected = '<?xml version="1.0" encoding="UTF-8" standalone="yes"?>' . "\n";
+        $objWriter->startElement('root');
+        $expected .= '<root>' . $indentnl;
+        $objWriter->startElement('node');
+        $expected .= $indent . '<node>';
+        $objWriter->writeRawData('xyz');
+        $expected .= 'xyz';
+        $objWriter->writeRawData(null);
+        $objWriter->writeRawData(['12', '34', '5']);
+        $expected .= "12\n34\n5";
+        $objWriter->endElement(); // node
+        $expected .= '</node>' . $indentnl;
+        $objWriter->endElement(); // root
+        $expected .= '</root>' . $indentnl;
+        self::assertSame($expected, $objWriter->getData());
+    }
 }