[R] Error in summary.warnings?

[Martin Maechler]

>>>>> Martin Maechler 
>>>>>     on Fri, 8 May 2020 17:37:29 +0200 writes:

>>>>> Allison Meisner 
>>>>>     on Thu, 7 May 2020 19:32:36 +0000 writes:

    > I believe there is an error in the summary.warnings function (typically called via 'summary(warnings())'). Below is a minimal working example:

    > #########

    > testfunction <- function(x){
    >  if(x > 30){
    >      warning("A big problem (should be 20 of these)")
    >  }else{
    >      warning("Bigger problem (should be 30 of these)")
    >  }
    > }

    > for(i in 1:50){
    >     testfunction(i)
    > }

    > summary(warnings())

    > #########

    > I checked the code for summary.warnings:

    > function (object, ...)
    > {
    >  msgs <- names(object)
    >  calls <- as.character(object)
    >  ss <- ": "
    >  c.m. <- paste(calls, msgs, sep = ss)
    >  if(length(i.no.call <- which(calls == "NULL")))
    >     c.m.[i.no.call] <- substr(c.m.[i.no.call],
    > 				  nchar(paste0("NULL", ss))+1L, 100000L)
    >  tm <- table(c.m., deparse.level = 0L)
    >  structure(unique(object), counts = as.vector(tm), class = "summary.warnings")
    > }


    >> The problem appears to be in the last line: unique preserves the order of the input, but counts reflects the counts in the table tm, which is a problem because table names are in alphabetical order.

I've committed the fix.  If you are interested,
I've replaced the last 2 lines with

    i.uniq <- which(!duplicated(object, incomparables=FALSE))
    tm <- table(factor(c.m., levels=c.m.[i.uniq]), deparse.level=0L)
    structure(object[i.uniq], counts = as.vector(tm), class = "summary.warnings")


which (at least conceptually) should even be faster the previous code.

Thank you again,
Martin

    >> Am I missing something?

    > No -- I think you are perfect and I was very imperfect ;-)  when
    > I created and tested the function ..

    > This will be fixed in the next versions of R.

    > Thank you very much for the report  and the nice concise
    > reproducible example!

    > Best regards,
    > Martin

    >> Allison
    >> ----------
    >> Allison Meisner, PhD
    >> Postdoctoral Fellow
    >> Department of Biostatistics
    >> Johns Hopkins Bloomberg School of Public Health
    >> 615 N. Wolfe Street
    >> Baltimore, MD 21205

    > Martin Maechler
    > ETH Zurich  and   R Core team

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