Investigate freeze/thaw behavior inconsistencies

[jcheng5]

1. reactiveVal thaws on onFlushed, reactiveValues... doesn't?
2. reactiveVal doesn't thaw on set, seems like both should (don't know if reactiveValues does)
3. Should we auto-unset all input$setMeta for a given slot when that slot is written to?

[jcheng5]

Here's an example of freezeReactiveValue not behaving correctly with a textInput that is re-rendered with its own value:

library(shiny)

ui <- fluidPage(
  uiOutput("ui"),
  actionButton("redraw", "Redraw"),
  p("Status:", textOutput("status", inline = TRUE))
)

server <- function(input, output, session) {
  output$ui <- renderUI({
    input$redraw
    freezeReactiveValue(input, "outval")
    textInput("outval", "Dynamic input", value = "hello")
  })
  
  output$status <- renderText({
    input$redraw
    tryCatch({
      input$outval
      "Thawed"
    }, error = function(err) {
      "Frozen"
    })
  })
}

shinyApp(ui, server)

If you click "Redraw" without changing the value from "hello", then the output only sees the input as frozen. The correct behavior would be for the input to only be frozen for a brief moment (the time between output$ui being refreshed and the text input being re-bound). The reason for this is because when the text input is re-bound, its value is the same as the last known value for the "outval" input, so nothing is sent to the server.

One solution for this would be for every bindInput to send values to the server regardless of whether it's a duplicate of the last value or not.

[jcheng5]

Similar problem as my previous comment, but this time with updateXXXInput:

library(shiny)

ui <- fluidPage(
  textInput("outval", "Dynamic input", value = "hello"),
  actionButton("update", "Update"),
  p("Status:", textOutput("status", inline = TRUE))
)

server <- function(input, output, session) {
  observeEvent(input$update, {
    freezeReactiveValue(input, "outval")
    updateTextInput(session, "outval", value = "hello")
  })

  output$status <- renderText({
    input$update
    tryCatch({
      input$outval
      "Thawed"
    }, error = function(err) {
      "Frozen"
    })
  })
}

shinyApp(ui, server)

The previous solution I proposed would not help for this case.

[fweber144]

Isn't this fixed and could be closed?