Importing some bad XLS file it could generate bunch of warnings "Uninitialized string offset"

[MekDrop]

It seems that in some cases count($recordData) < $pos, and the issue originates from this file: https://github.com/PHPOffice/PhpSpreadsheet/blob/5.1.0/src/PhpSpreadsheet/Reader/Xls.php#L2025

I'm not sure if I still have a bad file, since it happened overnight during the daily imports.
If I find one, I'll attach it later.

I can see two possible solutions here:

1. Silently fail
2. Throw an exception if the index is not found (I think this is probably the better option, since such files usually have a bad structure anyways).

I'm not sure which approach is preferred, but I could create a PR if needed (note: this would be my first PR).

Update: Found the file (compressed because github didn't let me upload) -> ddship.zip

[oleibman]

Yes, throwing an exception might be a better option, but, without a sample file that demonstrates this problem, we would be unlikely to merge a PR. Hopefully you can find one and post it.

[MekDrop]

@oleibman thanks for quick response. I attached the file on my original message

[oleibman]

@MekDrop Thank you for the sample file. As you have probably determined on your own, Excel considers the file corrupt and changes it in some manner before opening it. So it is not surprising that PhpSpreadsheet has a problem with it. I duplicate your result; now I have to think about how best to handle the situation.