`=1+` reported "unexpected `)`", although no `)` was typed: entry closes
missing parentheses by appending up to eight `)`, and when every retry
failed it reported the last retry's error. It now reports the error of
the formula as typed ("unexpected end of formula").
`gridcraft_formula::parse_closing_parens` holds the convenience and takes
the parse function, so cell entry and the UI's Spanish formula path share
it instead of each having its own loop.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Lower-casing then upper-casing made dotless ı equal to i (both become I),
which Unicode's default case folding keeps apart; LET(i,1,ı,2,i) could
return the ı binding. same_name now lower-cases and adds the folds lower
case misses (ß/ẞ -> ss, ſ -> s, ς -> σ). Tests cover ı/i and the Greek
final sigma.
- gridcraft_formula::same_name lower-cases then upper-cases each
character, so ß matches ẞ (to_uppercase alone maps ß to SS).
- Formula-bar input uses it too, so a binding such as ſi is not
translated to IF while the evaluator binds it.
- Tests: ISOMITTED with a case variant, ß/ẞ, and the Spanish input case.
A hostile file could abort any process that opens it: a cell formula of a
million `%` (`1%%%…`) or a 200,000-term sum parsed into trees deep enough to
overflow the stack when printed, saved, evaluated or dropped, even in release
builds. Postfix operators (`%`, invoking a result) built their nesting in a
loop that the 256-level limit did not see.
- `parse` refuses formula text longer than Excel's 8,192 characters
(`MAX_FORMULA_LEN`, counted in characters, the leading `=` excluded). This
also bounds the depth of the left-deep trees long operator chains build.
- Each postfix `%` and each call of a result counts towards the nesting limit.
- A file's formula that is refused keeps its text and cached value, as other
unparsable formulas do.
Regression tests: formula (small-stack thread: long `%`, invoke and operator
chains are errors; the limit counts characters, not bytes) and xlsx
(`hostile_formula_text_does_not_overflow_the_stack`: open, save and drop a
workbook with such formulas and a defined name on a 1 MiB stack). Both abort
with a stack overflow without the fix.
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
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