A Python cell whose cached value is empty (a file's PY formula with no cached
value) was taken for an empty cell by six checks, which use the value and the
formula only:
- the Analysis ToolPak report and the PivotTable report replaced it without
asking for overwrite or replace (CodeRabbit, on the report);
- Insert Cells and Insert Table without headers pushed it off the end of the
sheet;
- the data region (Ctrl+A, AutoSum, sort) ended at it;
- pasting it into part of a legacy array was not refused.
They now use Cell::has_content, which counts Python code.
Test: python_code_with_an_empty_value_counts_as_content; reverting any one of
the six changes makes it fail.
Structural edits, sheet renames and deletes, and a cut to another sheet
rewrite the xl() references in Python code, and could make a cell's code
longer than the 8,192-character limit that python.set enforces. Opening the
saved file then dropped that code to its value. Such an edit is now refused
with a message naming the cell, and nothing changes; keeping the old text
would have left a reference the edit had moved.
python.set kept the stored result whenever the code was unchanged, also when
the call switched the return type between an Excel value and a Python object.
The cell then showed a value and preview of the other type, and a save wrote
the new type with that old cached value. The result is now kept only when both
the code and the return type match; otherwise the cell is new code, which
shows #BLOCKED! until it runs, and its old spill goes with its readers
recalculated.
python.set, and Replace in a Python cell's code, removed the cell's spill
registration and its spilled values before the recalculation ran, so the
recalculation never saw the freed range and formulas reading those cells kept
their old values until a full recalculation. The commands now leave the spill
to the recalculation. When a Python cell's content changes and it has no array
result to lay out, cells_changed removes the spill and queues the freed range,
as it does for a formula replaced by a constant, so its readers are
recalculated; a cell that keeps its array result (the same code again) keeps
its spill and lays it out again. Clearing, pasting over and blocking a Python
spill already recalculated its readers, and undo and redo restore the values
along with the cells; a test covers them.
Save Model (new on main) asks before it replaces data in the column it writes
to, but it looked for a value or a formula only, so a Python cell whose cached
value is empty was taken for an empty cell and its code was replaced without
the question. Python code now counts as content there, as it does elsewhere.
Merge Across emptied the value and formula of the other cells in each row but
left their Python code, so a hidden cell stayed a Python cell with an empty
value and was saved as a PY formula. It now clears their whole content, as
Merge Cells and Merge & Center already did. In the same command, a merge
change evaluates again the blocked arrays that could reach the area, but only
formulas were picked, so a Python result blocked by a merged cell stayed
#SPILL! after the cells were unmerged; Python cells are picked too.
A cell formatted Hidden on a protected sheet hid its formula but not its
Python code: display::formula_hidden only looked for a formula at the cell (a
Python cell was covered only while its result spilled), and the formula bar
had its own check for formulas alone. Both now treat Python code as they treat
a formula, so the formula bar shows nothing for a hidden Python cell, as it
does for a hidden formula. Editing the cell is refused as before, because it
is locked.
Replace matched a Python cell on its code and then rebuilt the cell from the
replaced text as if it had been typed, so the cell became a text cell holding
the edited code and the Python cell was lost. The replacement now edits the
code: the cell stays a Python cell with its return type, its result is dropped
(#BLOCKED!, as for any changed code) and a spill it had is cleared. Code that
would no longer fit in a PY formula is left unchanged and counted in a new
skipped field of the result.
The footprint dry run and the per-step guard of macro runs (new on main)
compared formulas and values only. A step that replaced a Python cell with
its own cached value, or with other code that also shows #BLOCKED!, was not
counted as a write over data, so the code could be lost without the
question. A step that only blocked a Python cell's spill, which leaves its
code as it was, was counted as one. Python code is now content as a formula
is: a change of code or return type is a write, and a change of the cached
value alone is a recalculation.
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.
prxnvt