From phgrosjean at sciviews.org  Fri Sep  3 10:29:46 2010
From: phgrosjean at sciviews.org (Philippe Grosjean)
Date: Fri, 03 Sep 2010 10:29:46 +0200
Subject: [Rd] Weird erratic error and illogical error message,
 could someone explain this?
Message-ID: <4C80B1FA.9060403@sciviews.org>

Hello,

It's several days I try to track this bug, and even cannot cook a 
reproducible example. Yet, it occurs consistently in a long-running task 
after a variable period of time. Here is an example:

... my long-running code [as I said, cannot give something simple
that produces this bug in a reproducible manner]

Error in match(x, table, nomatch = 0L) :
     formal argument "nomatch" matched by multiple actual arguments
 > traceback()
6: match(x, table, nomatch = 0L)
5: "factor" %in% attrib[["class", exact = TRUE]]
4: structure(.Internal(Sys.time()), class = c("POSIXt", "POSIXct"))
3: Sys.time()
2: chemTrigger() at chemostat_1.0-1.R#1132
1: chemRun()

So, the culprid is a call inside `%in%` (from within structure() in 
Sys.time()). But I can run millions times `%in%`, or structure(), or 
Sys.time() on my machine without producing this bug. Arguments at 5: are 
simple character strings. They don't hurt!

Also, I am lost because the message is totally illogical in the context 
where it appears: I can understand this message here:

 > match(1, 2, nomatch = 0L, nomatch = NA)
Error in match(1, 2, nomatch = 0L, nomatch = NA) :
   formal argument "nomatch" matched by multiple actual arguments

or here:

 > test <- function (...) match(1, ..., nomatch = 0L)
 > test(2, nomatch = NA)
Error in match(1, ..., nomatch = 0L) :
   formal argument "nomatch" matched by multiple actual arguments

but in the call "match(x, table, nomatch = 0L)" where x is the character 
string "factor" and table is another character string ("numeric") 
extracted from a list, I don't understand why it produces this error 
message. '.Internal(Sys.time())' uses do_systime c code that returns a 
one-element double... not something that can hurt here?!

Can someone explain me, or give me an example where an argument is NOT 
duplicated in the call (well, as I understand it here) and where one 
gets such an error message? And why?

Many thanks, I am desperate :-(

I got this error on R 2.11.1 on Mac OS X 10.6.4, and on R 2.10.1 on 
Windows XP SP3 (but it does not matter, since I cannot cook a 
reproducible example).

Philippe

P.S.: seems related to this: 
http://finzi.psych.upenn.edu/Rhelp10/2008-June/165101.html
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  ) ) ) ) )
( ( ( ( (    Prof. Philippe Grosjean
  ) ) ) ) )
( ( ( ( (    Numerical Ecology of Aquatic Systems
  ) ) ) ) )   Mons University, Belgium
( ( ( ( (
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[Rd] Weird erratic error and illogical error message, could someone explain this?
Philippe Grosjean