Row groups merge when there is only one unique value in a rowname_col

[SJ-31]

Prework

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Description

If a row group X only has a single unique value in one of its rowname_col (with 2+ rowname_cols), the label for X will merge into the values of the preceding row group. Also, the group after X will merge into X's values

Reproducible example

• Post a minimal reproducible example so the maintainer can troubleshoot the problems you identify. A reproducible example is:
  • Runnable: post enough R code and data so any onlooker can create the error on their own computer.
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# Row group D only has `1` for rowname_col `symbol`
sample_data <- tibble::tibble(
  subject = c(rep("A", 3), rep("B", 4), rep("C", 2), rep("D", 2), rep("E", 3)),
  symbol = c(
    1,
    1,
    2,
    1,
    1,
    2,
    2,
    1,
    1,
    1,
    2,
    2,
    2,
    1
  ),
  value = runif(14),
  v2 = runif(14)
)
gt::gt(
  sample_data,
  rowname_col = c("symbol", "value"),
  groupname_col = "subject"
)

Expected result

Row group "D" shouldn't merge into the values of "C" and "E" shouldn't merge into the values of group "D".

Session info

^{Created on 2026-01-28 with reprex v2.1.1}

Session info

sessioninfo::session_info()
#> ─ Session info ───────────────────────────────────────────────────────────────
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#>  ui       X11
#>  language (EN)
#>  collate  en_US.UTF-8
#>  ctype    en_US.UTF-8
#>  tz       Asia/Bangkok
#>  date     2026-01-28
#>  pandoc   3.5 @ /usr/bin/ (via rmarkdown)
#>  quarto   1.8.27 @ /usr/bin/quarto
#> 
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#> 
#> ──────────────────────────────────────────────────────────────────────────────