onedrive_safe_xlsx

Edit .xlsx files with openpyxl without breaking OneDrive / SharePoint sync and version history.

The problem

openpyxl rebuilds a workbook from its own minimal model when it saves. A real Excel file has ~26 OOXML parts; openpyxl writes ~9 — it silently drops customXml/*, docProps/custom.xml, printerSettings, calcChain, and more.

On OneDrive/SharePoint those parts carry the document's identity and library binding. Strip them and your edits can:

• lose the file's version lineage (each save looks like a new/foreign file rather than a new version of the same document), and
• if you do preserve the parts but copy docProps/core.xml unchanged, its dcterms:modified / cp:revision stay the same, so SharePoint decides nothing changed and won't record a new version.

The fix

save_preserving() edits the data via openpyxl but:

1. Keeps every non-data part from the original file (identity preserved).
2. Updates the change-tracking in core.xml — dcterms:modified → now, cp:lastModifiedBy, and bumps cp:revision — so SharePoint logs a genuine new version.

Usage

import openpyxl
from onedrive_safe_xlsx import save_preserving

wb = openpyxl.load_workbook("Report.xlsx")   # an Excel/SharePoint-saved file
wb.active["A1"] = "edited"
save_preserving("Report.xlsx", wb, modified_by="Jane Doe")

Caveats

• Start from an Excel/SharePoint-saved copy — it has the parts to preserve. A file only ever written by openpyxl has nothing to preserve (open + save it in Excel once first).
• Uses datetime.now(timezone.utc) for the timestamp — cross-platform (Windows/macOS/Linux).
• Doesn't manage rsid co-authoring markers — intended for sequential (not concurrent) edits.

How to cite

If it helps your work, a credit is appreciated — GitHub's "Cite this repository" button uses CITATION.cff. The licence is permissive (Apache-2.0), so this is a request, not a requirement.

Licence

Apache-2.0 — see LICENSE. Copyright 2026 Jonathan Corcutt; attribution terms in NOTICE.