selectInput not working anymore within renderDataTable in 1.8.0

[Arthfael]

System details

Browser Version:

Output of sessionInfo():

> sessionInfo()
R version 4.3.1 (2023-06-16 ucrt)
Platform: x86_64-w64-mingw32/x64 (64-bit)
Running under: Windows Server 2022 x64 (build 20348)

Matrix products: default


locale:
[1] LC_COLLATE=English_United Kingdom.utf8  LC_CTYPE=English_United Kingdom.utf8    LC_MONETARY=English_United Kingdom.utf8
[4] LC_NUMERIC=C                            LC_TIME=English_United Kingdom.utf8    

time zone: Europe/Vienna
tzcode source: internal

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

other attached packages:
[1] DT_0.31     shiny_1.8.0

loaded via a namespace (and not attached):
 [1] digest_0.6.33     later_1.3.2       R6_2.5.1          httpuv_1.6.13     fastmap_1.1.1     magrittr_2.0.3    cachem_1.0.8      memoise_2.0.1    
 [9] htmltools_0.5.7   lifecycle_1.0.4   promises_1.2.1    cli_3.6.2         xtable_1.8-4      sass_0.4.8        jquerylib_0.1.4   compiler_4.3.1   
[17] rstudioapi_0.15.0 tools_4.3.1       bslib_0.6.1       mime_0.12         ellipsis_0.3.2    yaml_2.3.8        Rcpp_1.0.11       crayon_1.5.2     
[25] jsonlite_1.8.8    htmlwidgets_1.6.4 rlang_1.1.2       crosstalk_1.2.1

Example application or steps to reproduce the problem

require(shiny)
require(DT)

# Stand alone:
ui <- fluidPage(
  titlePanel(tag("u", "Test"), "Test"),
  h3("Now what is happening this time!?"),
  h3("Is this working?"),
  selectInput("Test", "", 1:5, 1, width = "100px"),
  br(),
)
server <- function(input, output, session) {
  observeEvent(input$Test, {
    cat(input$Test, "\n")
    Value <<- input$Test
  }, ignoreNULL = FALSE)
  session$onSessionEnded(function() { stopApp() })
}
print(shinyApp(ui, server, options = list(launch.browser = TRUE)))
Value
# -> Yes, this works...

# ... but as part of sapply: no!
tstTbl <- data.frame(Sample = 1:5, Choice = 1)
ui <- fluidPage(
  tags$head(tags$style(HTML("table {table-layout: fixed;"))), # So table widths can be properly adjusted!
  titlePanel(tag("u", "Test2"), "Test2"),
  DTOutput("tstTbl"),
  h3("And now!?"),
  br(),
)
server <- function(input, output, session) {
  tstTbl2 <- tstTbl
  tstTbl2$Choice <- sapply(seq_len(nrow(tstTbl2)), function(x) {
    as.character(selectInput(paste0("Test_", x), "", 1:5, 1, width = "100px"))
  })
  output$tstTbl <- renderDataTable(server = FALSE, escape = FALSE, selection = "none", editable = TRUE,
                                    rownames = FALSE,
                                    options = list(
                                      dom = 't', paging = FALSE, ordering = FALSE,
                                      autowidth = TRUE,
                                      scrollX = TRUE,
                                      preDrawCallback = JS('function() { Shiny.unbindAll(this.api().table().node()); }'),
                                      drawCallback = JS('function() { Shiny.bindAll(this.api().table().node()); } ')
                                    ), {
                                      tstTbl2
                                    })
  sapply(seq_len(nrow(tstTbl)), function(x) {
    id <- paste0("Test_", x)
    observeEvent(input[[id]], {
      cat(input[[id]], "\n")
      #tstTbl$Choice[x] <<- input[[id]]
    }, ignoreNULL = FALSE)
  })
  session$onSessionEnded(function() { stopApp() })
}
print(shinyApp(ui, server, options = list(launch.browser = TRUE)))

Describe the problem in detail

I am using a shiny app to edit tables of a variable number of samples, where for each sample I have to select one of several possible values. Up to now, I have been able to use sapply to create a selectInput() per sample, and similarly to create all corresponding observeEvent() using a second sapply. However, this has suddenly stopped working, see reprex above.
EDITS:

• As tested in my comment below, the issue is not the interaction between selectInput and multiple observeEvent instances generated through sapply (which works), but between selectInput and renderDataTable.
• I can now confirm that this is a recently introduced issue: downgrading to shiny_1.7.5 and DT_0.29 removes the issue - I have not investigated further.

[Arthfael]

Clearly I had not diagnosed the problem well: this is a problem of how selectInput interacts not with sapply,
but with DT:

# Testing interaction with sapply without table:
Values <- list(Test_1 = NA, Test_2 = NA)
ui <- fluidPage(
  titlePanel(tag("u", "Test"), "Test"),
  h3("Is just sapply working?"),
  selectInput("Test_1", "", as.character(1:5), "1", width = "100px"),
  selectInput("Test_2", "", as.character(1:5), "1", width = "100px"),
  actionButton("saveBtn", "Save"),
  br(),
)
server <- function(input, output, session) {
  sapply(1:2, function(x) {
    id <- paste0("Test_", x)
    observeEvent(input[[id]], {
      cat(input[[id]], "\n")
      Values[[id]] <<- input[[id]]
    }, ignoreNULL = FALSE)
  })
  observeEvent(input$saveBtn, { stopApp() })
  session$onSessionEnded(function() { stopApp() })
}
print(shinyApp(ui, server))
Values
# -> This works.

As a consequence, I have renamed the thread.

[stla]

See #3979
There are two options: either you set selectize=FALSE in selectInput. Or if you want to use selectize, you have to get and include the HTML dependency and to initialise the select inputs - see the above linked issue.