file descriptor leak in getSrcLines in R 2.10.0 svn 48590

I noticed the following file descriptor leak when I couldn't remove
a package unless I shut down the R session that had loaded and
used it.  The function that triggered the problem printed the output
of a call to parse().  Each time one prints a srcref a connection is
opened and not closed.  It looks like it happens in
as.character.srcref's
call to getSrcLines, which has some logic I don't understand about
closing 'srcfile' on exit only if !.is.Open(srcfile):

getSrcLines

function (srcfile, first, last)
{
    if (first > last)
        return(character(0L))
    if (!.isOpen(srcfile))
        on.exit(close(srcfile))
    conn <- open(srcfile, first)
    lines <- readLines(conn, n = last - first + 1L, warn = FALSE)
    srcfile$line <- first + length(lines)
    return(lines)
}

(It looks like the srcref stuff is not finished yet, as there are other
problems, like print(parse(file)) not showing what it used to.)

This is on Linux, compiled by me with an ancient version of gcc.

% R
R version 2.10.0 Under development (unstable) (2009-05-21 r48590)
...

showConnections()

     description class mode text isopen can read can write

tf<-tempfile()
cat(file=tf, "1:7\nlog(pi)\n")
showConnections()

     description class mode text isopen can read can write

p<-parse(tf)
showConnections()

     description class mode text isopen can read can write

p

expression(<srcref: file "/tmp/RtmpZ1llo5/file327b23c6" chars 1:1 to
1:3>,
    <srcref: file "/tmp/RtmpZ1llo5/file327b23c6" chars 2:1 to 2:7>)
attr(,"srcfile")
/tmp/RtmpZ1llo5/file327b23c6

showConnections()

  description                    class  mode text   isopen   can read
can write
3 "/tmp/RtmpZ1llo5/file327b23c6" "file" "rt" "text" "opened" "yes"
"no"
4 "/tmp/RtmpZ1llo5/file327b23c6" "file" "rt" "text" "opened" "yes"
"no"
5 "/tmp/RtmpZ1llo5/file327b23c6" "file" "rt" "text" "opened" "yes"
"no"
6 "/tmp/RtmpZ1llo5/file327b23c6" "file" "rt" "text" "opened" "yes"
"no"

tf

[1] "/tmp/RtmpZ1llo5/file327b23c6"

z<-attr(p,"srcref")[[2]]
showConnections()

  description                    class  mode text   isopen   can read
can write
3 "/tmp/RtmpZ1llo5/file327b23c6" "file" "rt" "text" "opened" "yes"
"no"
4 "/tmp/RtmpZ1llo5/file327b23c6" "file" "rt" "text" "opened" "yes"
"no"
5 "/tmp/RtmpZ1llo5/file327b23c6" "file" "rt" "text" "opened" "yes"
"no"
6 "/tmp/RtmpZ1llo5/file327b23c6" "file" "rt" "text" "opened" "yes"
"no"

zz<-as.character(z)
showConnections()

  description                    class  mode text   isopen   can read
can write
3 "/tmp/RtmpZ1llo5/file327b23c6" "file" "rt" "text" "opened" "yes"
"no"
4 "/tmp/RtmpZ1llo5/file327b23c6" "file" "rt" "text" "opened" "yes"
"no"
5 "/tmp/RtmpZ1llo5/file327b23c6" "file" "rt" "text" "opened" "yes"
"no"
6 "/tmp/RtmpZ1llo5/file327b23c6" "file" "rt" "text" "opened" "yes"
"no"
7 "/tmp/RtmpZ1llo5/file327b23c6" "file" "rt" "text" "opened" "yes"
"no"

zz

[1] "<srcref: file \"/tmp/RtmpZ1llo5/file327b23c6\" chars 2:1 to 2:7>"

Bill Dunlap
TIBCO Software Inc - Spotfire Division
wdunlap tibco.com