How to properly close the Chromote session in a package?

[stla]

Hello,

I've made a RStudio addin with chromote (it uses a JavaScript library to reindent some code).

I do as follows to close the Chromote session:

  ......
  result <- session$Runtime$evaluate("editor.getValue();")
  value <- result$result$value
  on.exit(session$close())
  value

Is it ok? I read somewhere that to really shut down the session, one has to do session$parent$close(). But if I do that my package does not work, I get the error Chromote object is closed.

[stla]

I've just seen this SO thread and then I tried:

  parentBrowser <- session$parent$get_browser()
  on.exit(parentBrowser$close())

Then the package works but I get this message:

[2023-07-01 02:40:26] [error] handle_read_frame error: asio.system:10054 (An existing connection was forcibly closed by the remote host.)

[stla]

This throws a true R error. And RCMD Check complains that there are connections style open at the end.

[stla]

I get that when I check my package:

 > cleanEx()
Error: -07-19 09:56:21] [error] handle_read_frame error: websocketpp.transport:7 (End of File)
  Error: connections left open:
  	/tmp/RtmpI2u7Qc/working_dir/RtmpSVIMYD/supervisor_stdin1da34ccd933f (fifo)
  	/tmp/RtmpI2u7Qc/working_dir/RtmpSVIMYD/supervisor_stdout1da37a2efa39 (fifo)
  Execution halted

[stla]

I read somewhere that to really shut down the session, one has to do session$parent$close(). But if I do that my package does not work, I get the error Chromote object is closed.

I know why this error occurs.

The session$parent$close function is:

function () {
    private$is_active_ <- FALSE
    self$Browser$close()
}

And the session$Browser$close function calls self$send_command. But in the send_command function, there is:

    if (!private$is_active_) {
        stop("Chromote object is closed.")
    }

Hence the error.

[wch]

Thanks for the investigation into the problem! I've just pushed a fix for it.

[stla]

Thanks! Does this fix solves the RCMD Check problem with the unclosed connection ?

Oddly, I don't have this problem when I RCMD Check on my Windows laptop, but it occurs on Ubuntu in the Github action.

[wch]

Hm, I'm not sure about R CMD check. It looks like the workflow on this repo was disabled automatically due to inactivity. I just re-enabled it, but I'm not sure if it's possible to kick off another run without pushing a new commit.

Update: I just pushed a commit to trigger the GHA workflow.

[stla]

I've just tested your fix and session$parent$close() returns FALSE.

[wch]

I've just tested your fix and session$parent$close() returns FALSE.

That just happens to be the value of the last expression in the function. Do you think it should return something else?

[stla]

session$close() returns TRUE. I thought this means "ok, the session has been closed". The FALSE is misleading for me.

[wch]

OK, I just pushed a change so that it returns TRUE when it closes. Subsequent calls to $close() return FALSE.