R devel - Jul 2005 - Minor "bug" in source()

For R v2.1.1 patched and R v2.2.0 devel:

Calling source(file, chdir=TRUE) with is.character(file) != TRUE, that 
is, with 'file' as a connection, will generate an error. Example:

 > file <- textConnection("cat('Hello world\n')")
 > source(file, chdir=TRUE)
Error in source(file, chdir = TRUE) : Object "ofile" not found

Of course, it does not make sense to change working directory, but 
quietly ignoring 'chdir' is better, I think.

This is due to a simple coding mistake in source() [sorry, 56k modem
=> no R source => no diff]:

<snip></snip>
     if (is.character(file)) {
         ofile <- file
         if (capabilities("iconv")) {
             if (identical(encoding, "unknown")) {
         <snip></snip>
     }
     Ne <- length(exprs <- .Internal(parse(file, n = -1, NULL,
         "?")))
     if (verbose)
         cat("--> parsed", Ne, "expressions; now eval(.)ing
them:\n")
     if (Ne == 0)
         return(invisible())
     if (chdir && is.character(ofile)) {        <=== HERE
         isURL <- length(grep("^(ftp|http|file)://", ofile)) >
             0
         if (!isURL && (path <- dirname(ofile)) != ".") {
             owd <- getwd()
             on.exit(setwd(owd), add = TRUE)
             setwd(path)
         }
     }
<snip></snip>

I suggest to either i) do 'ofile <- file' before the first if-clause 
above, or better ii) move the last if-clause inside the first one (and 
remove " && is.character(ofile)").

Best

Henrik

I think at least a warning is appropriate here (and also for a URL), so 
have modified the code to have one in each case.

There is a reason why the chdir code is later, after the parsing, for it 
was thought more important to get an error from parsing than from failing 
to chdir.

On Tue, 19 Jul 2005, Henrik Bengtsson wrote:
> For R v2.1.1 patched and R v2.2.0 devel:
>
> Calling source(file, chdir=TRUE) with is.character(file) != TRUE, that
> is, with 'file' as a connection, will generate an error. Example:
>
> > file <- textConnection("cat('Hello world\n')")
> > source(file, chdir=TRUE)
> Error in source(file, chdir = TRUE) : Object "ofile" not found
>
> Of course, it does not make sense to change working directory, but
> quietly ignoring 'chdir' is better, I think.
>
> This is due to a simple coding mistake in source() [sorry, 56k modem
> => no R source => no diff]:
>
> <snip></snip>
>     if (is.character(file)) {
>         ofile <- file
>         if (capabilities("iconv")) {
>             if (identical(encoding, "unknown")) {
>         <snip></snip>
>     }
>     Ne <- length(exprs <- .Internal(parse(file, n = -1, NULL,
>         "?")))
>     if (verbose)
>         cat("--> parsed", Ne, "expressions; now
eval(.)ing them:\n")
>     if (Ne == 0)
>         return(invisible())
>     if (chdir && is.character(ofile)) {        <=== HERE
>         isURL <- length(grep("^(ftp|http|file)://", ofile))
>
>             0
>         if (!isURL && (path <- dirname(ofile)) != ".")
{
>             owd <- getwd()
>             on.exit(setwd(owd), add = TRUE)
>             setwd(path)
>         }
>     }
> <snip></snip>
>
> I suggest to either i) do 'ofile <- file' before the first
if-clause
> above, or better ii) move the last if-clause inside the first one (and
> remove " && is.character(ofile)").
>
> Best
>
> Henrik
>
> ______________________________________________
> R-devel at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel
>
>
-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
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