FreeTDS Development Group

["Ivo van der Wijk" <vladdrac AT gmail.com>]

Hi All

I'm currently using a very recent nightly build (feb 5) of FreeTDS. We
need the recently added   timeout code and it works (mostly) as a
charm.

However, in certain cases, when a timeout occurs (which I simply test
by unplugging the utp), FreeTDS (and python, Zope which I use it for
along with it) dies with the following assertion errror:

buffering.h:233: failed assertion `buffer_index_valid(buf, idx)'

Essentially, this happens in dblib.c function dbnextrow(), and I
suspect because of the following.

In this function the following code path is executed:

      if (-1 != (idx = buffer_current_index(dbproc))) {
            (...)
               switch (tds_process_tokens(tds, &res_type, NULL, mask)) {
                (...)
                default:
                        result = FAIL;
                        break;
                }
        }
        if (res_type == TDS_ROW_RESULT || res_type == TDS_COMPUTE_RESULT) {
                buffer_transfer_bound_data(&dbproc->row_buf, res_type, 
computeid,
dbproc, idx);
        }
       (...)
       return result;

In case of 'default', which sets result to FAIL, the next if is still
evaluated, causing buffer_transfer_bound_data to be invoked, which
triggers the assertion error.

Immediately returning FAIL in the default clause fixes my problem
currently. In other words:

                default:
                      return FAIL;


It would probably be more elegant to test 'result' in the remaining if
statements, and return result at the end of the function.

Can anyone verify that this is a proper bug and proper fix? I'm far
from a FreeTDS expert, and my C is rather rusty. But this does seem to
fix my problem for now.

Kind regards,

 Ivo van der Wijk

--
Drs. I.R. van der Wijk / m3r Consultancy B.V.
Linux/Python/Zope/Plone and Open Source solutions
PO-box 51091, 1007 EB Amsterdam, The Netherlands
Email: ivo <at> m3r.nl