suppressPackageStartupMessages in a future

[ismirsehregal]

I'm wondering how I can suppress package startup messages when the dependencies are collected by {future}.

This "issue" came up in the context of a shiny app (messages started to show up a few month ago, this problem did not exist previously) - please find a reproducible example below.

Once the actionButton is pressed and the task is first invoked in a fresh R session messages from library(bit64) are displayed.

Loading required package: bit [...]

This is not the case once I explicitly specify the namespace of the function (bit64::any.integer64).

However, in my actual code I'm not using a bit64 function directly it is called by {data.table} so I don't have control regarding this.

suppressPackageStartupMessages({
  library(future)
  library(shiny)
  library(bit64)
})

plan(multisession)

myTask <- ExtendedTask$new(function() {
  future({
    suppressPackageStartupMessages({
      library(bit64)
    })
    any.integer64(2)
    # bit64::any.integer64(2) # no package start-up message
  }, seed = 1L, stdout = FALSE)
})

ui <- fluidPage(
  actionButton("go", "go"),
  textOutput("text")
)

server <- function(input, output, session) {
  observeEvent(input$go, {
    myTask$invoke()
  })
  
  output$text <- renderText({
    if(myTask$status() == "success"){
      paste(myTask$result(), collapse = ", ")
    }
  })
}

shinyApp(ui, server)

PS: a similar discussion can be found here:

#787

However, the fix doesn't (or no longer) seem to work in my case.

[HenrikBengtsson]

Hi, here's a minimal reproducible example of the problem:

library(future)
plan(multisession)

suppressPackageStartupMessages({
  library(bit64)
})

f <- future({
  any.integer64(2)
})

Calling:

v <- value(f)

, which I think is what myTask$result() calls internally, will relay the packageStartupMessage that was generated on the parallel worker.

To prevent packageStartupMessage conditions from being relayed back to the main R session, we can tell the future to not collect such conditions in the first place;

library(future)
plan(multisession)

suppressPackageStartupMessages({
  library(bit64)
})

f <- future({
  any.integer64(2)
}, conditions = structure("condition", exclude = "packageStartupMessage"))
v <- value(f)
v
#> [1] TRUE

PS. I can imagine this will become a FAQ. Having to write conditions = structure("condition", exclude = "packageStartupMessage")) for such a common use case might be a bit tedious. Maybe that should be the new default rather than conditions = "condition" - I'll think about it (EDIT +10min: now tracked in #803)

[ismirsehregal]

Ah - thanks for the heads-up!

[HenrikBengtsson]

BTW, I think you could also muffled the startup message with:

  output$text <- renderText({
    if(myTask$status() == "success"){
      paste(suppressPackageStartupMessages(myTask$result()), collapse = ", ")
    }
  })

Please let me know if that works - that could be helpful for others to know.

[ismirsehregal]

That was actually one of the things I tried before I started the discussion here. Unfortunately it doesn't help.