What did your actual application do? This seems a very strange thing
to do, and the segfault is in trying to construct the traceback.
Only by using do.call on the object (and not even by name) do I get
this error. E.g.
`[.data.frame`(1:10, 3)
Error in NextMethod("[") : object not specified
do.call("[.data.frame", list(1:10, 3))
Error in NextMethod("[") : object not specified
are fine.
Obviously it would be nice to fix this, but I'd like to understand the
actual circumstances: there is more to it than the subject line.
On Thu, 29 Jan 2009, brechbueh...@gmail.com wrote:
Full_Name: Christian Brechbuehler
Version: 2.7.2, 2.8.1
OS: linux-gnu
Submission from: (NULL) (24.128.51.18)
Calling [.data.frame on an object that's not a data frame, specifically 1:10,
causes segmentation fault.
Context
=======
We can subscript with a number of different notations:
> (1:10)[3]
[1] 3
> do.call(get("[",pos="package:base"),list(1:10,3))
[1] 3
> do.call(get("[.numeric_version",pos="package:base"),list(1:10,3))
[1] 3
Problem
=======
If we mistakenly believe the object is a data frame (as we did in a much more
complicated real situation), this happens:
> do.call(get("[.data.frame",pos="package:base"),list(1:10,3))
Error in NextMethod("[") :
no calling generic was found: was a method called directly?
*** caught segfault ***
address (nil), cause 'unknown'
Process R:2 segmentation fault (core dumped) at Thu Jan 29 09:26:29 2009
The Error message is appropriate. But the segmentation fault is unexpected.
Versions
========
I reproduced the problem on R 2.7.2 and 2.8.1. Details:
version
_
platform x86_64-unknown-linux-gnu
arch x86_64
os linux-gnu
system x86_64, linux-gnu
status Patched
major 2
minor 7.2
year 2008
month 09
day 20
svn rev 46776
language R
version.string R version 2.7.2 Patched (2008-09-20 r46776)
==========================================================
version
_
platform x86_64-unknown-linux-gnu
arch x86_64
os linux-gnu
system x86_64, linux-gnu
status Patched
major 2
minor 8.1
year 2009
month 01
day 26
svn rev 47743
language R
version.string R version 2.8.1 Patched (2009-01-26 r47743)
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--
Brian D. Ripley, rip...@stats.ox.ac.uk
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
University of Oxford, Tel: +44 1865 272861 (self)
1 South Parks Road, +44 1865 272866 (PA)
Oxford OX1 3TG, UK Fax: +44 1865 272595
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