Incorrect reader used for CSV files with BOM

[SchmidtClaudia]

This is:

• [x] a bug report

What is the expected behavior?

Reading an CSV file with IOFactory::load($file) should use the Csv Reader no matter whether the file starts with a BOM or not. The HTML Reader should do further checks regarding tags after finding a BOM.

What is the current behavior?

The HTML reader checks if the file starts with a BOM and returns true without any further syntax checks.

I think the bug was introduced with this change https://github.com/PHPOffice/PhpSpreadsheet/commit/09c9a310a03f62777c0ce83beae49946fb3984d0#diff-914de62bf54eee4a88135dcbbbce0cf9a59ad5c08b21ac454e645d2bad2390caR151

What are the steps to reproduce?

1. Create a CSV file starting with a BOM.
2. Try to load the file with IOFactory::load($file)

see my test in https://github.com/PHPOffice/PhpSpreadsheet/pull/4029

What features do you think are causing the issue

• [x] Reader

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

CSV, HTML

Which versions of PhpSpreadsheet and PHP are affected?

5.1.0