Attributes renderUI has a weird behavior

[earnaud]

Running the app returns a valid Attribute module for the UI part with such HTML:

<textarea id="fill-Attributes-nitrogen.csv-date-attributeDefinition" class="form-control shinyjs-resettable" data-shinyjs-resettable-id="fill-Attributes-nitrogen.csv-date-attributeDefinition" data-shinyjs-resettable-type="TextArea" data-shinyjs-resettable-value="Description for date">Description for date</textarea>

(above, the input for describing a "date" attribute)

BUT:

when asking for names(input), this is empty. No idea why, still investigating.

This topic is dedicated to help this issue to be solved if met by anyone else furtherly in the shinyverse.

[earnaud]

Here is a reproducible example. The bug seems to occur from the module server part initiating without UI being set. Therefore, listeners listen to NULL.

library(shiny)

test_UI <- function(id) {
  ns <- NS(id)
  tagList(
    textInput("test", "test")
  )
}

test_server <- function(id, rv) {
  moduleServer(id, function(input, output, session) {
    observeEvent(input$test, {
      rv$text <- input$test
    })
  })
}

ui <- fluidPage(
  actionButton("dev", "dev"),
  uiOutput("test")
)

server <- function(input, output, session) {
  rv <- reactiveValues(
    text = ""
  )
  
  output$test <- renderUI({
    test_UI("outer")
  })
  
  test_server("outer")
  
  observeEvent(input$dev, {
    browser()
  })
}

shinyApp(ui, server)

EDIT

Well, no.

[earnaud]

** Solved **

The JS console (right-click > inspect element > errors) showed that an ID was duplicated while rendering the attributes edit area. Thus, this one did not render anything at all.

Morale: in absence of errors, first check these logs.