Cell gains `py: Option<Arc<PyCode>>`, read with a serde default and not
written for ordinary cells, so older native files load and ordinary
cells serialize as before. PyCode holds the code, the return type (an
Excel value or a Python object), the last result (value, type name,
preview, whether it converted to cells) and a stale flag for manual
calculation. The cell's `value` stays the cached result, so formulas,
display and saving read a Python cell like any other. is_blank,
CellStore::has and input_text (which returns the code) take the code
into account; Cell::has_content and clear_content cover value, formula
and code together.
The model reads and writes the PY function's syntax as Microsoft
documents it, PY("chunk"&"chunk",0|1), with string literals of at most
255 characters and the return type 0 for an Excel value, 1 for a Python
object. The reader takes the `_xlfn._xlws.` prefix (and `_xlfn.` or
`_xlws.` alone, in any letter case); to_file_formula writes it. (An xlsx
file keeps the code in its Python part instead; the xlsx commit adds
it.) The size limit is Excel's 8,192 characters for that formula, not a
count of code characters: doubled quotes and the "&" between literals
count, so code with many quotes fits in fewer characters (8,079
characters of plain code fit exactly). The model also finds the
xl("...") literals in code, skipping comments and other strings; a plain
literal may escape a quote or a backslash. A rewritten reference that
holds the literal's quote (a sheet name that needs quotes, 'Q4
2026'!B2) takes the other quote as the literal's delimiter, or an
escaped quote when it holds both, so it never ends the string early.
Edits: cell.set over a Python cell, Clear Contents, Clear All and the
cells a merge empties remove the code; Clear Formats keeps it. Copy and
paste (All, Formulas), Fill, sort, cut-move, sheet copy and undo carry
it; a cut to another sheet first qualifies its xl() references with the
source sheet, as a moved formula's references are, so they keep
reading the same cells. Paste Values and Paste Link do not carry it,
and paste operations do not combine numbers with a Python cell. Fill
copies Python cells instead of extending them as a series. cell.set
with =PY(...) is refused with a message that points to python.set, and
Text to Columns keeps a piece that reads as =PY(...) as text instead of
clearing it. Goal Seek refuses a Python cell as its changing cell, and
Solver as a variable cell, as both refuse formulas: the number written
there would replace the code. The sheet-protection check compares the
code, so a locked Python cell cannot be changed. cell.get reports
{python: code, output, typeName, preview, stale}.
The xl() literals follow reference-moving edits: rewrite_all_formulas
(row and column insert and delete, cell insert and delete, cut-move),
sheet rename and sheet delete adjust each literal like a formula
reference, and replace it only when it changed.
Errors: CellError gains Python, Busy, Timeout and Blocked, and ALL has
14 entries, so the lexer reads them as literals. ERROR.TYPE gives 11 for
#BLOCKED!, the number Excel returns. Microsoft documents no ERROR.TYPE
number for #PYTHON!, #BUSY! or #TIMEOUT!; they take 19, 20 and 21, after
the numbers Excel is known to use. The xlsx writer caches the four as
#VALUE!, as it already does #SPILL! and #CALC!, because they are not
error codes of the file format.
Tests cover the =PY refusal, removal by entry and clearing, undo, copy,
paste values, fill and sort, xl() rewrites through row insert, sheet
rename (also to names that need quotes, with one quote and with both),
cut-move (also to another sheet) and column delete, Goal Seek and
Solver refusing Python cells, Text to Columns keeping a =PY piece,
native JSON round trips, the new errors, the prefixes, escaped quotes in
literals, and the encoded size limit at 8,192 characters exactly and
with doubled quotes.
Found while testing crates/xlsx/src/csv.rs:204 (write_csv_limited, starts at sheet.used_range().start instead of A1)
Co-Authored-By: Claude Haiku 5.5 <noreply@anthropic.com>
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
write_csv visited every position of the used range and appended to one growing
String with no limit, so two cells far apart (A1 and XFD1048576) asked for
about 16 GiB of commas. The output is now capped at 512 MiB: a lower bound
(delimiters and line ends of every row) is checked before anything is
allocated, and the text written so far is checked after each row. Over the
cap, write_csv returns IoError::TooLarge naming the rows, columns and limit,
and Save As / Export CSV and TSV report it without writing a file. Accepted
exports are unchanged. write_csv now returns a Result.
A `;`-separated CSV (the usual CSV where `,` is the decimal separator) was
rewritten with `,` on save: read_csv sniffed the delimiter but the result was
dropped, and save_bytes passed a hard-coded b','. file.save, Save As .csv,
file.exportCsv, file.saveBytes and gridcraft-cli convert all went through it.
The workbook now remembers the separator it was read with
(Workbook::csv_delimiter, set by read_csv) and a CSV save writes it back.
Workbooks not read from CSV, and .tsv/.txt sources saved as .csv, keep `,`.
Regression tests: `;`, `,` and tab .csv round trips byte for byte, new and
.xlsx-origin workbooks save with `,`, and open-by-path + edit + file.save on a
`;` file keeps `;` (also through exportCsv and saveBytes).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
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