paper-xlsxAPI referencepreserve.crosscheck
openpyxl.preserve.crosscheck
paper-xlsx 0.2.1 API reference
Cross-check the splice output against the ledger's claims.
A cell the splice changed that the ledger never recorded is corruption INSIDE the safety tooling — a release-blocking bug class — so this check raises hard, never warns. Enabled via PAPER_LEDGER_CROSSCHECK=1 (the paper test suite turns it on for every preserve-mode save it performs).