- richTextPrefix visits at most maxCellTextChars + 1 runs. An empty run adds
no text, so a length check alone walked every run of a shared string for
every cell referencing it, on every tile.
- Two or more unsupported number format warnings in a tile fold into one
"N unsupported number formats" entry, and the notice bar has a max-height
and scrolls.
- General-format and unsupported-format numbers render at 15 significant
digits, as Excel does (0.1+0.2 shows 0.3).
- TIME_FORMAT accepts a trailing AM/PM, so h:mm AM/PM renders as 2:30 PM
instead of falling back to a date.
- SPREADSHEET_ASSET_VERSION refreshed.
ExcelJS keeps a row's cells at `_cells[col - 1]`, so a row whose only
cell sits in XFD is a dictionary-mode array that `eachCell` and
`hasValues` (behind `eachRow`) walk to index 16,384. The worker walked
each row four times at load and once per tile, so a small file of
far-column rows took seconds to load and to tile.
`worksheetMetadata` now builds each sheet's row and cell index from
`Object.keys(sheet._rows)` and `Object.keys(row._cells)`, sorted
numerically, skipping falsy and Null-type cells exactly as
`eachCell({ includeEmpty: false })` does and keeping a row only when it
holds one such cell (`hasValues`). Styles, extent and row heights come
from that one pass and merges from `sheet._merges`; `sendTile` reads
each row's cells from the index.
`parseThemePalette` returns the default palette for a theme above
64 * 1024 characters, since its patterns are quadratic on unclosed tags.
ExcelJS stores a row at _rows[r - 1] and a sheet at _worksheets[sheetId], and
walks or slices those arrays up to the largest index, so the index a row or
sheet claims is a cost of its own. Admission now reads each <row> tag's
attributes in order and refuses an r outside 1-1048576 (absent r is fine), and
a counter for the resolved xl/workbook.xml reads every <sheet> tag and refuses
one that does not parse or whose sheetId is not plain digits up to
LIMITS.maxSheetId (65535).
sendTile no longer reads sheet.model, which rebuilt every row and cell model on
each tile: the merges read in worksheetMetadata are kept in mergesById next to
populatedRowsById, replaced on load and cleared on dispose.
Number formats cap decimals at 30, as Excel does; toLocaleString throws a
RangeError above 100 and the whole grid was replaced by the error.
Docs: CLAUDE.md and architecture-invariants describe both bounds and the merge
reuse. SPREADSHEET_ASSET_VERSION is recomputed for the edited worker and core.
Admission checked ZIP entry names as stored, but JSZip (inside ExcelJS)
resolves `.`, `..` and empty segments on load, and ExcelJS strips one
leading `/` and matches worksheets with an unanchored pattern. Names like
`/xl/worksheets/sheet1.xml` or `xl/worksheets/sheet1.xml.x` skipped every
counter. Admission now computes the name ExcelJS will see for each entry,
refuses two entries that resolve to the same name, keys the rebuilt
archive on it, and picks the worksheet/styles counters from it.
ExcelJS's DefinedNames model setter expands every range into one object
per cell. The preview never shows defined names, so the worker stubs
`_definedNames.model` before load.
Pin fflate to 0.8.3 (GHSA-px8p-9vwx-vf98) and refresh
SPREADSHEET_ASSET_VERSION.
XML allows a raw `>` and the other quote character inside an attribute
value, so a first-match search for `ref=`/`max=` could be fed a fake
value from an earlier attribute while saxes read the real one:
- <mergeCell>/<col> attributes are now read in order from the tag name
with a sticky regex that consumes each quoted value whole. A tag whose
attributes do not parse up to `>`, or that repeats a name, is refused.
- The chunk carry keeps everything from the last `<`, which can never
appear inside an attribute value, instead of comparing against the
last `>`.
ExcelJS keeps a Row object for every <row>, cells or not, so <row> tags
now count against per-sheet (100k) and total (250k) caps with their own
row-limit code, and the worker passes maxRows as a per-sheet backstop.
styles.xml counts every <xf> without tracking which list it sits in,
since a </cellXfs> inside a comment desynced that state.
ExcelJS 4.4.0 expands three constructs into one object per cell or column
at load time, so a few KB admitted as one cell could cost a gigabyte:
- a <mergeCell> now costs its full area against the per-sheet and total
cell caps, and a ref that does not parse is refused
- a <col> whose min or max is past 16384 is refused
- the worker loads with ignoreNodes: ['dataValidations']; the preview
never shows validations, and a whole-column dropdown took 5 s
The XML counter now scans up to the last complete tag and carries the
rest, so a merge or col tag cut by an inflate-chunk edge is read whole.
A central-directory compressedSize that runs past the file is refused,
since the ratio cap divides by it.
The renderer and core axis offsets use prefix sums with a binary search
instead of walking every override per call.
- Normalize the value shapes ExcelJS loads before formatting: Date cells are
formatted from their serial (UTC), so they no longer render as a local-time
string a day early at negative UTC offsets; rich text joins its runs,
hyperlinks show their text, error values show the error, and formula and
shared-formula results (including error results) recurse. Excel serials are
rounded to whole milliseconds so 00:05 no longer shows as 00:04.
- sendTile() skips hidden rows and columns, and at the 2500-cell cap returns a
truncated tile with a warning instead of failing the whole preview.
- ExcelJS now parses a STORE-only archive rebuilt from exactly the entries
admitXlsx() inflated and counted, never the fetched bytes. Admission walks
local headers while JSZip reads the central directory, so overlapping
entries could show the two readers different sheets. A duplicate local
entry name is refused. The theme fallback reads the admitted entry too.
- Row and column headings take their size from the same axis math as cells.
- Document the admission, worker-only loading and SPREADSHEET_ASSET_VERSION
rules in architecture-invariants, and list .xlsx in the attachments panel
help and the `codeman attach` error text (built from the accepted list).
xlsx files were download-only. Add a read-only, virtualized preview (sheet
tabs, number formats, merges, theme colours) parsed entirely in a browser
Web Worker with exceljs and fflate, loaded only when a spreadsheet is
opened. The workbook is checked against ZIP-bomb, entry and cell limits
before exceljs loads; cell text is written with textContent, formulas are
never evaluated and nothing referenced by the workbook is fetched. On the
server xlsx only joins the existing allowlist and classification, with a
10 MB cap on ?preview=true. xls and ods stay download-only.
Aamer Akhter