scattermapbox non-circle marker symbols not shown in legend since v4.12.0

Since upgrading to plotly 4.12.0, only the "circle" symbol is rendered correctly in the legend for scattermapbox traces. Other marker symbols (e.g. "diamond", "square") are no longer displayed — the legend shows a blank entry for those.

v 4.12.0

v 4.11.0

(note that already in previuos versions, the non-circle markers were not shown on the canvas itself, but this was not an issue in our use case, because we only wanted to create the custom legend with the square markers)

reprex

library(plotly)

symbols_to_try <- c(
  "circle",
  "diamond",
  "square",
  "marker"
)

traces <- lapply(seq_along(symbols_to_try), function(i) {
  list(
    type       = "scattermapbox",
    mode       = "markers",
    lon        = i * 2,
    lat        = 51,
    name       = symbols_to_try[i],
    showlegend = TRUE,
    hoverinfo  = "name",
    marker     = list(
      color  = "steelblue",
      size   = 20,
      symbol = symbols_to_try[i]
    )
  )
})

p <- plotly_empty() |>
  layout(
    mapbox = list(
      style  = "carto-positron",
      center = list(lon = 5, lat = 51),
      zoom   = 3
    ),
    legend = list(x = 1, xanchor = "right", y = 1)
  ) |>
  config(displaylogo = FALSE)

for (tr in traces) {
  p <- add_trace(p,
    inherit    = FALSE,
    type       = tr$type,
    mode       = tr$mode,
    lon        = tr$lon,
    lat        = tr$lat,
    name       = tr$name,
    showlegend = tr$showlegend,
    hoverinfo  = tr$hoverinfo,
    marker     = tr$marker
  )
}

p

packageVersion("plotly")

Further info:

The legend (and markers on canvas) work fine with "scattergeo" or even "scatter", but it has other side-effects in our setting that makes the plot be drawn twice, even if setting the layout like

plotly::layout(
    plotly_object,
    geo = list(
      visible = FALSE,
      showframe = FALSE,
      showcoastlines = FALSE,
      showland = FALSE,
      showocean = FALSE
    )
  )

提供された R reprex を scattermapbox トレースで開始し、plotly 4.11.0 と 4.12.0 の間で凡例の動作を比較します。マーカーシンボルが add_trace を通じてどのように渡されるかを追跡し、scattermapbox の凡例処理を調査します。circle、diamond、square、marker のエントリが、scattergeo や scatter の動作に影響を与えずに正しくレンダリングされれば完了です。