Xml::loadSpreadsheetFromString() tries to open file when using falsy argument

[Rudloff]

This is:

• a bug report
• a feature request
• not a usage question (ask them on https://stackoverflow.com/questions/tagged/phpspreadsheet or https://gitter.im/PHPOffice/PhpSpreadsheet)

What is the expected behavior?

Calling Xml::loadSpreadsheetFromString() with any value should never try to load a file from disk.

What is the current behavior?

Calling loadSpreadsheetFromString(0) tries to load a file named 0 and triggers this warning:

PHP Warning:  file_get_contents(0): Failed to open stream: No such file or directory in /home/pierre/www/fuzzer/vendor/phpoffice/phpspreadsheet/src/PhpSpreadsheet/Reader/Xml.php on line 114

I think this happens because of $this->fileContents ?: file_get_contents($filename), any fileContents value that is evaluated as false triggers file_get_contents().

What are the steps to reproduce?

Please provide a Minimal, Complete, and Verifiable example of code that exhibits the issue without relying on an external Excel file or a web server:

<?php

require __DIR__ . '/vendor/autoload.php';

$reader = new \PhpOffice\PhpSpreadsheet\Reader\Xml();
$reader->loadSpreadsheetFromString(0);

If this is an issue with reading a specific spreadsheet file, then it may be appropriate to provide a sample file that demonstrates the problem; but please keep it as small as possible, and sanitize any confidential information before uploading.

What features do you think are causing the issue

• Reader
• Writer
• Styles
• Data Validations
• Formula Calculations
• Charts
• AutoFilter
• Form Elements

Does an issue affect all spreadsheet file formats? If not, which formats are affected?

I think only the XML reader is affected.

Which versions of PhpSpreadsheet and PHP are affected?

2.0.0