[chaliy]

Requested by Михайло · project thread

What changed

First slice of the #11 follow-ups (format detection, correctness, panic profile):

• Single-row sheets now render the row as data under its Excel column letters (| A | B |), and count in stats.rows. Before, the row became a header with no data rows.
• Spreadsheet titles: Extraction.title is filled for XLSX (docProps/core.xml), ODS (meta.xml) and XLS (SummaryInformation, code-page aware). Best effort: a malformed property part gives None, never an error.
• XLSB detection: application/vnd.ms-excel.sheet.binary.macroEnabled.12, .xlsb and xl/workbook.bin containers map to the new Format::Xlsb instead of Xlsx. XLSB is still rejected with UnsupportedFormat here; the reader comes in a follow-up PR.
• Missing _rels/.rels: XLSX packages without it get the standard officeDocument relationship before calamine opens them, so they parse.
• panic = "unwind" in the release profile, so the catch_unwind guard actually works in the CLI and the Python/Node bindings. Before, a parser panic aborted the process.
• Trailing newline: kept, now documented as intended (non-empty output ends with exactly one \n).

Why

These gaps showed up while making markkit fetchkit's Office backend (#11).

Before / After

single.xlsx (openpyxl, one row, title "FY26 Summary"):

Before (main):

## Totals

| Q1 | 100 | Q2 | 120 |
| --- | --- | --- | --- |

title: null

After:

## Totals

| A | B | C | D |
| --- | --- | --- | --- |
| Q1 | 100 | Q2 | 120 |

title: "FY26 Summary"

just fmt lint test check-okf test-scripts examples pass locally. cargo deny is not installed locally and runs in CI.

Risk

• Low
• Output change for single-row sheets (intended). Format gains a variant (#[non_exhaustive], so not breaking). Slightly larger release binaries with unwind tables.

Checklist

• Tests added or updated (single row, titles for all three formats, malformed property sets, missing _rels, XLSB content type; new fuzz fixtures)
• Backward compatibility considered

Part of #11

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Generated by Claude Code