`selectedpoints` does not function properly when a vector is passed using `plotlyProxy` & `"restyle"`.

Bug/Unexpected Behavior

When updating a scatter plot's selectedpoints in a Shiny server using "restyle" on a plotlyProxy, single value vectors don't update the graph. E.g., passing c(1) to selectedpoints won't update the graph.

However, if we duplicate this value, e.g., c(1, 1) and pass it to selectedpoints, the 1 point will be selected.

Reproducible example:

# selected points single value incorrect behavior
library(shiny)

ui <- fluidPage(fluidRow(plotly::plotlyOutput("graph"),
                         DT::DTOutput("table")))

server <- function(input, output, session) {
  output$table <- DT::renderDT({
    cars
  })
  
  output$graph <- plotly::renderPlotly({
    plotly::plot_ly(
      cars,
      x = ~ speed,
      y = ~ dist,
      selected = list(marker = list(color = "red")),
      type = "scatter",
      mode = "markers",
      source = "graph"
    ) %>%
      plotly::layout(dragmode = "select",
                     clickmode = "event+select") %>%
      plotly::event_register("plotly_selected")
  })
  
  plot_proxy <- plotly::plotlyProxy("graph")
  table_proxy <- DT::dataTableProxy("table")
  
  selected <-
    reactive({
      plotly::event_data("plotly_selected", source = "graph")
    })
  
  observeEvent(selected(), {
    selected <- selected()$pointNumber + 1
    table_proxy %>% DT::selectRows(selected)
  })
  
  observeEvent(input$table_cell_clicked, {
    selected_rows <- input$table_rows_selected - 1

   #### comment this conditional to see the bug ####
    if (length(selected_rows) == 1) {
      selected_rows <- rep(selected_rows, 2)
    }
   #### end comment this conditional to see the bug ####

   plotly::plotlyProxyInvoke(
      plotly::plotlyProxy("graph", session),
      "restyle",
      list(selectedpoints = list(selected_rows)),
      0
    )
  })
  
}

shinyApp(ui, server)

Start by running the supplied R Shiny reproducible example and compare plotlyProxyInvoke with selected_rows containing c(1) versus c(1, 1). Trace the selectedpoints update through the plotlyProxy "restyle" call; done means a single-value vector selects the point without duplication.