Undefined symbol (Rf_PrintWarnings) when using rpy 2.3.1 and R 3.0.1

So it seems the version of rpy2 (2.3.1) that comes with Ubuntu Raring isn't currently compatible with the version of R (3.0.1) in CRAN.

If you try to import it you'll get something like this:

$ python
Python 2.7.4 (default, Apr 19 2013, 18:28:01) 
[GCC 4.7.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import rpy2
>>> import rpy2.rinterface
Traceback (most recent call last):
  File "", line 1, in 
  File "/usr/lib/python2.7/dist-packages/rpy2/rinterface/__init__.py", line 93, in 
    from rpy2.rinterface._rinterface import *
ImportError: /usr/lib/python2.7/dist-packages/rpy2/rinterface/_rinterface.so: undefined symbol: Rf_PrintWarnings

However, the solution is pretty straightforward.

First download the source for rpy2 2.3.1. Then extract it and edit the file rpy2-2.3.1/rpy/rinterface/_rinterface.c. Then comment out the following on lines 1764-1765:

  extern void Rf_PrintWarnings(void);
  Rf_PrintWarnings(); /* show any warning messages */

Such that it appears as:

  //extern void Rf_PrintWarnings(void);
  //Rf_PrintWarnings(); /* show any warning messages */

Change to the rpy2-2.3.1 directory where you extracted the source to and reinstall rpy2 using:

sudo python setup.py install

Which should allow it to work again.

$ python
Python 2.7.4 (default, Apr 19 2013, 18:28:01) 
[GCC 4.7.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import rpy2
>>> import rpy2.rinterface
>>> 

You won't get any of the warning messages that Rf_PrintWarnings() would have output when it calls an R function.  This has already been fixed in the development branch but this quick fix means you don't have to wait for an official update to get rpy2 running again.