Excel.decodeBytes crashes on valid XLSX file (Parser._parseTable)

[mhanuska-coder]

Description:

Environment:

Flutter
excel: 4.0.6

Problem:

Excel.decodeBytes() crashes with:

Null check operator used on a null value

Stack trace:

Parser._parseTable
Parser._parseContent
Excel.decodeBytes

Important observation:

The XLSX file opens normally in Microsoft Excel 2021.

Workaround that fixes the issue 100%:

Open the problematic XLSX file in Excel.
Save it as XLS (Excel 97-2003 Workbook).
Open the XLS file.
Save it again as XLSX.
The new XLSX file loads correctly with Excel.decodeBytes().

This suggests that the parser has a problem with some XLSX structures generated by newer Excel formats, while the XLS->XLSX conversion rewrites the workbook into a format that the parser can read correctly.

[almasumdev]

try excel_plus fast and works great
https://pub.dev/packages/excel_plus

[gonojuarez]

"Now exist two options on Flutter environment to parse XLS files: excel_community or excel_plus. Both are forks of the Excel library, and the authors are ready to implement new features. @almasumdev is the dev of excel_plus and I'm the dev of excel_community.

By the way, regarding the Null check operator in _parseTable, this is a known issue with how the old parser handles certain modern XLSX structures. I am currently tracking/have patched this in excel_community, so it decodes safely without needing the XLS workaround."