Plotly does not show error message when inputs are invalid for Quarto dashboards in R

[angelchen7]

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

Hi Quarto team, I believe I encountered a bug when plotly is used with shiny::validate() for Quarto dashboards in R.

I could not get plotly::renderPlotly() to work well with shiny::validate() when invalid values are inputted. Instead of showing the error message specified by validate() when there's an invalid input, renderPlotly() will display the previous plot. As far as I know, this bug only occurs for Quarto dashboards (.qmd) and does not appear in regular R scripts (.R). I have included an MRE below.

I appreciate any insight or tips. Thank you so much.

Steps to reproduce

---
title: "Testing renderPlotly with shiny::validate()"
format: dashboard
server: shiny
---
```{r}
#| label: setup
library(shiny)
library(plotly)
library(ggplot2)
```

```{r}
sliderInput("min_mpg", "Minimum MPG:", min = 10, max = 30, value = 15)
plotlyOutput("myPlot")
```

```{r}
#| context: server
output$myPlot <- renderPlotly({
  # Validate that the input value is within an acceptable range
  validate(
    need(input$min_mpg >= 10 && input$min_mpg <= 25, 
         "Please select a minimum MPG between 10 and 25.")
  )
  
  # Filter data based on the validated input
  filtered_mtcars <- mtcars[mtcars$mpg >= input$min_mpg, ]
  
  # Create a ggplot object
  p <- ggplot(filtered_mtcars, aes(x = wt, y = mpg)) +
    geom_point() +
    labs(title = paste("Cars with MPG >= ", input$min_mpg))
  
  # Convert ggplot to plotly
  ggplotly(p)
})

```

Actual behavior

When the user input, input$min_mpg, exceeds the range of valid inputs set by validate() (10 to 25 in this example), renderPlotly() will display the previous, outdated plot like so:

Expected behavior

What I expected was for renderPlotly() to respect all the parameters set by validate(), which means that it should've displayed the specified error message when it detected that input$min_mpg was an invalid input over 25 like so:

Your environment

-IDE: RStudio 2024.09.1+394
-OS: MacOS Sequoia 15.6.1

Quarto check output

Quarto 1.8.26
[✓] Checking environment information...
      Quarto cache location: /Users/ac3656/Library/Caches/quarto
[✓] Checking versions of quarto binary dependencies...
      Pandoc version 3.6.3: OK
      Dart Sass version 1.87.0: OK
      Deno version 2.3.1: OK
      Typst version 0.13.0: OK
[✓] Checking versions of quarto dependencies......OK
[✓] Checking Quarto installation......OK
      Version: 1.8.26
      Path: /Applications/quarto/bin

[✓] Checking tools....................OK
      TinyTeX: (not installed)
      Chromium: (not installed)

[✓] Checking LaTeX....................OK
      Tex:  (not detected)

[✓] 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 Python 3 installation....OK
      Version: 3.9.6
      Path: /Library/Developer/CommandLineTools/usr/bin/python3
      Jupyter: 5.7.2
      Kernels: python3

(|) Checking Jupyter engine render....Traceback (most recent call last):
  File "/Applications/quarto/share/jupyter/jupyter.py", line 20, in <module>
    from notebook import notebook_execute, RestartKernel
  File "/Applications/quarto/share/jupyter/notebook.py", line 15, in <module>
    from yaml import safe_load as parse_string
ModuleNotFoundError: No module named 'yaml'
There is a requirements.txt file in this directory. Is this for a venv that you need to restore?

WARN: Error encountered when rendering files
[✓] Checking Jupyter engine render....OK

[mcanouil]

This seems to be very specific as without plotly or without using dashboard format (i.e., using html), everything is as expected.
Required: dashboard + shiny + plotly

---
title: "Testing renderPlotly with shiny::validate()"
format: dashboard
server: shiny
---

```{r}
#| label: setup
library(shiny)
```

```{r}
sliderInput("min_mpg", "Minimum MPG:", min = 10, max = 30, value = 15)
textOutput("text")
```

```{r}
#| context: server
output$text <- renderText({
  # Validate that the input value is within an acceptable range
  validate(
    need(
      input$min_mpg >= 10 && input$min_mpg <= 25,
      "Please select a minimum MPG between 10 and 25."
    )
  )
  paste("You have selected a minimum MPG of:", input$min_mpg)
})
```

[angelchen7]

Hi, thank you for taking a look! Yes, I believe this bug is specific to the Quarto dashboard as the exact code from my MRE works as expected when I run it as a plain .R script (I've included it below for ease of use in case anyone wants to check).

library(shiny)
library(plotly)
library(ggplot2)

ui <- fluidPage(
  sliderInput("min_mpg", "Minimum MPG:", min = 10, max = 30, value = 15),
  plotlyOutput("myPlot")
)

server <- function(input, output) {
  output$myPlot <- renderPlotly({
    # Validate that the input value is within an acceptable range
    validate(
      need(input$min_mpg >= 10 && input$min_mpg <= 25, 
           "Please select a minimum MPG between 10 and 25.")
    )
    
    # Filter data based on the validated input
    filtered_mtcars <- mtcars[mtcars$mpg >= input$min_mpg, ]
    
    # Create a ggplot object
    p <- ggplot(filtered_mtcars, aes(x = wt, y = mpg)) +
      geom_point() +
      labs(title = paste("Cars with MPG >= ", input$min_mpg))
    
    # Convert ggplot to plotly
    ggplotly(p)
  })
}

# Works as expected, the error message will display correctly
shinyApp(ui, server)