fix(xlsx): tolerate legacy showZeroes sheet views

[Yufeng He (he-yufeng)]

Fixes #2063.

Some XLSX files still contain the worksheet view attribute name showZeroes. openpyxl 3.1+ expects showZeros, so loading those files raises a TypeError before MarkItDown can read the workbook.

This keeps the normal pandas/openpyxl path unchanged. If that path fails with the known showZeroes TypeError, MarkItDown rewrites worksheet XML entries in memory from showZeroes to showZeros and retries the read. The fallback is scoped to worksheet XML files and only runs for that specific compatibility error.

Validation:

• .venv\Scripts\python.exe -m pytest packages\markitdown\tests\test_module_misc.py -q -k "xlsx_legacy_show_zeroes"
• .venv\Scripts\python.exe -m pytest packages\markitdown\tests\test_module_vectors.py::test_convert_local -q
• .venv\Scripts\python.exe -m py_compile packages\markitdown\src\markitdown\converters_xlsx_converter.py packages\markitdown\tests\test_module_misc.py
• .venv\Scripts\python.exe -m ruff check packages\markitdown\src\markitdown\converters_xlsx_converter.py packages\markitdown\tests\test_module_misc.py
• git diff --check

[Yufeng He (he-yufeng)]

Friendly ping for maintainer review. The CLA check is green, and the current patch is limited to the openpyxl showZeroes compatibility fallback plus a regression test. Please let me know if you want the compatibility path shaped differently.

[Copilot]

🟡 Changes recommended

The unrestricted byte replacement can silently modify inline worksheet cell values.

Once you've addressed the issues Copilot identified, you can request another Copilot review.

Pull request overview

Adds XLSX compatibility handling for legacy showZeroes worksheet attributes.

Changes:

• Retries XLSX parsing after an in-memory worksheet XML repair.
• Adds an end-to-end regression test for legacy workbooks.

File summaries

File	Description
_xlsx_converter.py	Implements compatibility fallback and retry.
test_module_misc.py	Tests legacy workbook conversion.

Review details

• Files reviewed: 2/2 changed files
• Comments generated: 1
• Review effort level: Balanced

---

💡 Add a code-review agent skill or configure MCP servers for context-aware, tailored reviews. Learn more in the docs.

[Copilot]

🟢 Approval recommended

The fallback is narrowly scoped, preserves normal behavior, and has appropriate regression coverage.

Review details

• Files reviewed: 2/2 changed files
• Comments generated: 0 new
• Review effort level: Balanced