What does “Error in tools:::httpdPort <= 0L : …” in Rstudio means?

Question

I have upgraded R to version 3.2.2. When I restart Rstudio, before \">\" is shown, there is an error message:

Error in tools:::httpdPort <= 0L :
        c         


        

Answer 1

I just encountered the same problem today and searched through the source code to understand the origin. The reason is that until R 3.1.3, httpdPort was a variable, while since R 3.2.0, it is a function.

The error occurs, because the line

tools:::httpdPort <= 0L

is wrong, if httpdPortis a function. It should rather be

tools:::httpdPort() <= 0L

It seems that RStudio runs that line at some point and of course, it needs to know, which of the two versions to run. This is why RStudio needs to be updated after R is updated from a version <= 3.1.3 to a version >= 3.2.0.

The httpdPort is defined in the file src/library/tools/R/dynamicHelp.R. In R version 3.1.3, the definition reads

httpdPort <- 0L

while in R version 3.2.0, it is

httpdPort <- local({
    port <- 0L
    function(new) {
        if(!missing(new))
            port <<- new
        else
            port
    }
})

To solution to the problem is thus to either downgrade your R version to <= 3.1.3 or to upgrade RStudio.