shinyTree with "&" in list names disconnects on shinyapps.io

[psimm]

When a list passed to renderTree contains multiple & symbols, and the app is hosted on shinyapps.io, the server disconnects and a notification saying: "attempting to reconnect" keeps flashing. I passed this to the RStudio support and they reproduced the problem and recommended I file an issue here.

I can't reproduce the issue locally on macOS 10.15.6 or on Ubuntu 18.04 LTS running R 3.6.3 with shiny 1.5.0 and shinyTree 0.2.7 from CRAN. So it could be related to the Linux or Shiny server environment.

Here is a sample app:

library(shiny)
library(shinyTree)

tree <- list(
   A = structure(list(
     `Gifts & Sets` = structure(0, stselected = TRUE),
     Jewellery = structure(0, stselected = TRUE),
     `Socks & Tights` = structure(0, stselected = TRUE),
     Tweezers = structure(0, stselected = TRUE)
  ), stselected = TRUE),
  B = structure(list(
     `Gifts & Sets` = structure(0, stselected = TRUE),
     `Hand & Feet` = structure(list(
        Treatments = structure(0, stselected = TRUE)
     ), stselected = TRUE)
   ), stselected = TRUE)
)

shinyApp(
   ui = fluidPage(shinyTree("tree")),
   server = function(input, output) {
      output$tree <- renderTree(tree)
   }
)

And here is the app on shinyapps.io: https://psim.shinyapps.io/shiny_tree_test/

Removing any single line, even the Jewellery item for example, caused the issue to disappear on shinyapps.io.

I understand that this is a rare niche use case and debugging it may not be worth the time. For practical use the issue is fixed by removing the & from the list names.

[trafficonese]

Did you check the shinyapps.io Logs? Maybe there is some useful information.

And btw. the link you provided works for me.

[psimm]

Hi @trafficonese thanks for the reply.

Yes I checked the logs and the RStudio support team checked them too. Nothing about the connection problem, unfortunately. Here they are:

2020-09-29T09:45:46.358636+00:00 shinyapps[2781829]: Starting R with process ID: '24'
2020-09-29T09:52:53.507691+00:00 shinyapps[2781829]: Running on host: feea4c37cf1c
2020-09-29T09:52:53.512858+00:00 shinyapps[2781829]: Server version: 1.8.4.1-20
2020-09-29T09:52:53.512871+00:00 shinyapps[2781829]: R version: 3.6.3
2020-09-29T09:52:53.512903+00:00 shinyapps[2781829]: knitr version: (none)
2020-09-29T09:52:53.512871+00:00 shinyapps[2781829]: LANG: en_US.UTF-8
2020-09-29T09:52:53.512877+00:00 shinyapps[2781829]: shiny version: 1.5.0
2020-09-29T09:52:53.512886+00:00 shinyapps[2781829]: httpuv version: 1.5.2
2020-09-29T09:52:53.512895+00:00 shinyapps[2781829]: rmarkdown version: (none)
2020-09-29T09:52:53.512911+00:00 shinyapps[2781829]: jsonlite version: 1.6.1
2020-09-29T09:52:53.681610+00:00 shinyapps[2781829]: Using jsonlite for JSON processing
2020-09-29T09:52:53.512922+00:00 shinyapps[2781829]: RJSONIO version: (none)
2020-09-29T09:52:53.512938+00:00 shinyapps[2781829]: htmltools version: 0.5.0
2020-09-29T09:52:53.513072+00:00 shinyapps[2781829]: Using pandoc: /opt/connect/ext/pandoc2
2020-09-29T09:52:53.684513+00:00 shinyapps[2781829]:
2020-09-29T09:52:53.684515+00:00 shinyapps[2781829]: Starting R with process ID: '154'
2020-09-29T09:52:53.758031+00:00 shinyapps[2781829]:
2020-09-29T09:52:53.758032+00:00 shinyapps[2781829]: Listening on http://127.0.0.1:43265

And nothing after that.

You don't get an "attempting to reconnect" at the bottom left of the screen?

[trafficonese]

Oh sry I think I checked my local app.
So yes indeed, I see that panel flashing but the app seems functional somehow.

What if you replace all & with \u0026 and all backticks with normal ticks?

[psimm]

Sorry I can't test that right now, I will get back to it tomorrow evening.

[psimm]

Do you mean to change the tree to this?

tree <- list( 
  A = structure(list( 
    'Gifts \u0026 Sets' = structure(0, stselected = TRUE), 
    Jewellery = structure(0, stselected = TRUE), 
    'Socks \u0026 Tights' = structure(0, stselected = TRUE), 
    Tweezers = structure(0, stselected = TRUE) 
  ), stselected = TRUE), 
  B = structure(list( 
    'Gifts \u0026 Sets' = structure(0, stselected = TRUE), 
    'Hand \u0026 Feet' = structure(list( 
      Treatments = structure(0, stselected = TRUE) 
    ), stselected = TRUE) 
  ), stselected = TRUE)) 

I have made that change and uploaded it to Shinyapps.io. Here is the app: https://psim.shinyapps.io/shinytree_test2/

[trafficonese]

Ok, that didn't help. The problem doesn't come from the & character.
I created another app, with this tree and didn't get any disconnects:

tree <- list(
    A = structure(list(
        'Gifts & Sets' = structure(0, stselected = TRUE),
        Jewellery = structure(0, stselected = TRUE),
        'Socks & Tights' = structure(0, stselected = TRUE)
    ), stselected = TRUE),
    B = structure(list(
        'Gifts ! Sets' = structure(0, stselected = TRUE),
        Jewellery = structure(0, stselected = TRUE),
        'Socks $ Tights' = structure(0, stselected = TRUE)
    ), stselected = TRUE)
)