[Python-bugs-list] Reference counting problem? (PR#338)

gpk@bell-labs.com gpk@bell-labs.com
Wed, 24 May 2000 10:24:33 -0400 (EDT)

Full_Name: Greg Kochanski
Version: 1.6 as of 5/21/2000
OS: Solaris 2.6
Submission from: h-135-104-33-130.research.bell-labs.com (

Python 1.6 seems to have some kind of reference counting problem.

The following function (in the midst of a large program)
will crash with a nonsensical exception if I comment out the
print statement.

def _pull_types(d, nc):
        """Finds all the column definitions in the data file,
        that is, attributes in the form 'TTYPE#'.   These
        attributes tell you what kind of data is in a specific
        column.  It then builds an output dictionary that
        tells you what column contains any desired type of data."""

        ts = type('')
        kl = d.keys()
        o = {}
        for k in kl:
                assert type(k)==ts, 'Key must be string'
		# comment out next line to crash:
                print "PULLTYPES(", k, ")", 'type(k)=', type(k)
                if len(k)>5 and k[:5] == 'TTYPE':
                        col = string.atoi(k[5:])
                        if col>0 and col<=nc:
                                o[d[k]] = col-1
        return o

Output with print statement in:

PULLTYPES( HISTORY ) type(k)= <type 'string'>
PULLTYPES( _FILETYPE ) type(k)= <type 'string'>
PULLTYPES( I_NOISE ) type(k)= <type 'string'>
PULLTYPES( NAXIS2 ) type(k)= <type 'string'>
PULLTYPES( CDELT2 ) type(k)= <type 'string'>
PULLTYPES( CDELT1 ) type(k)= <type 'string'>

Output with print statement commented out:

Traceback (most recent call last):
  File "/u/gpk/f0cls/bin/get_3_f0.sh", line 101, in ?
    pegg = get_f0(t + '/pegg.sd', pfile+'.pegg', t + '/pegg');
  File "/u/gpk/f0cls/bin/get_3_f0.sh", line 83, in get_f0
    return gpkimgclass.read(ttn + '.f0.dat')
  File "/home/gpk/lib/gpkimgclass.py", line 41, in read
    return gpk_img(hdr, data)
  File "/home/gpk/lib/gpkimgclass.py", line 69, in __init__
    self.types = _pull_types(self.hdr, self.n[1])
  File "/home/gpk/lib/gpkimgclass.py", line 23, in _pull_types
    if len(k)>5 and k[:5] == 'TTYPE':
IndexError: list index out of range