Table Attr (id, classes, attributes) is silently dropped when tbl-colwidths triggers a SimpleTable round-trip

I have:

• searched the issue tracker for similar issues
• installed the latest version of Quarto CLI
• formatted my issue following the Bug Reports guide

Bug description

Bug description

resolve_table_colwidths_scoped (in share/filters/modules/tablecolwidths.lua) applies column widths by round-tripping the table through pandoc.utils.to_simple_table / from_simple_table. SimpleTable has no Attr, so the rebuilt table loses its identifier, classes and attributes.

This is invisible for tables labelled the normal Quarto way ({#tbl-x} in the caption), because crossref carries the id on a wrapping div. It bites when a user Lua filter sets el.identifier (or el.attr) on a Table: the attribute is present in the AST until the pre-scope-resolution step and gone right after it.

With the HTML default tbl-colwidths: auto, the round-trip is triggered by the mere presence of a Link anywhere in the table — the auto branch scans for links and, if it finds one, zeroes the computed widths. So the symptom looks arbitrary from the outside: tables with links lose their id, tables without links keep it.

With tbl-colwidths: false or an explicit list, the attributes are lost for every table, link or no link.

Notes

Related but not the same:

• #7072 (closed): {#tbl-x tbl-colwidths="[…]"} declared in the caption of a book project.
• #13776 (closed by #14096): the same to_simple_table / from_simple_table round-trip, losing a different thing — merged cells. The fix added an is_simple(tbl) guard that bails out when the table has spans, but the round-trip is still lossy for Attr on every other table, so the guard doesn't cover this case.
  A guard for spans and a silent Attr loss suggest the round-trip itself is the wrong tool here; setting the widths on tbl.colspecs directly would avoid both.

Steps to reproduce

filter.lua:

function Table(el)
  el.attr = pandoc.Attr("my-id", {"my-class"}, {{"data-mine", "1"}})
  return el
end

_quarto.yml:

project:
  type: default
filters:
  - filter.lua
format:
  html:
    toc: false

with-link.qmd:

---
title: With link
---
 
| A | B |
|---|---|
| one | [two](https://example.org) |
 
: Caption.

without-link.qmd — the same file, with the cell two instead of the link.

Then quarto render with-link.qmd without-link.qmd --to html.

Actual behavior

<!-- without-link.html -->
<table id="my-id" class="my-class caption-top table" data-mine="1">
 
<!-- with-link.html -->
<table class="caption-top table">

QUARTO_TRACE_FILTERS=trace quarto render with-link.qmd shows the Attr intact through pre-output-location and empty at pre-scope-resolution, which is where resolve_scoped_elements runs resolve_table_colwidths_scoped.

Setting tbl-colwidths: true keeps the Attr in both files — that branch returns nil and never rebuilds the table. Setting tbl-colwidths: false or [50,50] loses it in both.

Expected behavior

Applying column widths should preserve the table's Attr. Something like reassigning result.attr = tbl.attr after from_simple_table, or setting the widths on tbl.colspecs directly instead of going through SimpleTable.

Your environment

Quarto 1.10.18 (also reproduced on 1.5.57)

• macOS
• Not R/Python specific: plain .qmd, no engine.

Quarto check output

❯ quarto check
Quarto 1.10.18
[✓] Checking environment information...
Quarto cache location: /Volumes/macmini external ssd/eukeni_external/Library/Caches/quarto
[✓] Checking versions of quarto binary dependencies...
Pandoc version 3.10.0: OK
Dart Sass version 1.101.0: OK
Deno version 2.7.14: OK
Typst version 0.15.1: OK
[✓] Checking versions of quarto dependencies......OK
[✓] Checking Quarto installation......OK
Version: 1.10.18
Path: /Applications/quarto/bin

[✓] Checking tools....................OK
TinyTeX: (not installed)
Chrome Headless Shell: (not installed)
VeraPDF: (not installed)

[✓] Checking LaTeX....................OK
Using: Installation From Path
Path: /Library/TeX/texbin
Version: 2025

[✓] Checking Chrome Headless....................OK
Using: Chrome found on system
Path: /Applications/Google Chrome.app/Contents/MacOS/Google Chrome
Source: MacOS known location

[✓] Checking basic markdown render....OK

[✓] Checking R installation...........(None)

  Unable to locate an installed version of R.
  Install R from https://cloud.r-project.org/

[✓] Checking Python 3 installation....OK
Version: 3.14.6
Path: /opt/homebrew/opt/python@3.14/bin/python3.14
Jupyter: (None)

  Jupyter is not available in this Python installation.
  Install with python3 -m pip install jupyter

[✓] Checking Julia installation...

Start in share/filters/modules/tablecolwidths.lua at resolve_table_colwidths_scoped and trace the to_simple_table/from_simple_table round-trip used for tbl-colwidths. Reproduce the issue with filter.lua and the with-link.qmd and without-link.qmd examples, then verify that rendered tables preserve their identifier, classes, and attributes across the affected tbl-colwidths settings.