[Rd] file descriptor leak in getSrcLines in R 2.10.0 svn 48590

[Duncan Murdoch]

On 5/21/2009 2:17 PM, William Dunlap wrote:
> 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):

I have a simpler recipe to reproduce the crash now:

tf <- tempfile()
con <- file(tf, open="w", encoding="unknown")

This gives an error message about an unsupported conversion
and leaves the con object only partially built. closeAllConnections() 
will then crash.

Should be relatively easy to fix...I'll take a look.

Duncan Murdoch

> 
>> 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 
> 
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