[Bug-readline] Readline + Python + GDL => Seg fault

[Gregory Novak]

GDL is a free implementation of the IDL programming language that can
be built as a Python module to allow one to call IDL code from Python.
http://gnudatalanguage.sourceforge.net/

When "enough" of readline has been activated, I get a seg fault with
the backtrace listed below when trying to call any GDL code from
Python. I've also reported this problem there on the Python and GDL
mailing lists.

One way to initialize enough of readline is to use IPython
(http://ipython.scipy.org), an enhanced interactive Python shell (this
is how I found the bug). Another way is to follow the instructions
from IPython's author (no IPython required) listed below.

I am using:
OS X 10.4.8
Python 2.4.2 (#1, Mar 22 2006, 21:27:43) 
[GCC 4.0.1 (Apple Computer, Inc. build 5247)] on darwin
GDL 0.9 pre 3
readline 5.0

Greg Novak

----------------------------------------------------------------------
Message from Fernando Perez:

Here's how to crash plain python (at least it works reliably on my
ubuntu box).  Paste this into an interactive session (don't try to
execfile, you have to paste it as if you had typed it interactively so
readline has to work):

import os
import readline

''' Some gibberish here is needed that's long enough to trigger the bug.  I'm
not sure how much data is actually required...

12jd lsjlksajsa jfl;ksaj34567890
123asdjf lkasdj flkajs l;kfd4567890
123asdflkasdj fl;saj f;a4567890
12jd lsjlksajsa jfl;ksaj34567890
123asdjf lkasdj flkajs l;kfd4567890
123asdflkasdj fl;saj f;a4567890
12jd lsjlksajsa jfl;ksaj34567890
123asdjf lkasdj flkajs l;kfd4567890
123asdflkasdj fl;saj f;a4567890
'''

try:
   __histfile = os.path.join(os.environ['HOME'],'.python-history')
   readline.read_history_file(__histfile)
except IOError:
   pass  # History file doesn't exist yet.

# This will now cause a crash:

import GDL
print GDL.function("sin",(1,))

# EOF

----------------------------------------------------------------------
Backtrace:
Program received signal EXC_BAD_ACCESS, Could not access memory.
Reason: KERN_PROTECTION_FAILURE at address: 0x00000000
0x00556304 in call_readline (sys_stdin=0x699b20, sys_stdout=0x697f40, prompt=0x5
56c70 "") at /Volumes/Panther/sw.build/python24-2.4.2-1004/Python-2.4.2/Modules/
readline.c:885
885     /Volumes/Panther/sw.build/python24-2.4.2-1004/Python-2.4.2/Modules/readl
ine.c: No such file or directory.
        in /Volumes/Panther/sw.build/python24-2.4.2-1004/Python-2.4.2/Modules/re
adline.c
(gdb) bt
#0  0x00556304 in call_readline (sys_stdin=0x699b20, sys_stdout=0x697f40, 
prompt=0x556c70 "") at 
/Volumes/Panther/sw.build/python24-2.4.2-1004/Python-2.4.2/Modules/readline.c:885
#1  0x000bc0bc in PyOS_Readline (sys_stdin=0xa0001b9c, sys_stdout=0xa0001bf4, 
prompt=0x5b36d6c "\n\001\033[0;34m\002In 
[\001\033[1;34m\0022\001\033[0;34m\002]: \001\033[0m\002") at 
Parser/myreadline.c:208
#2  0x000a4cac in builtin_raw_input (self=0x0, args=0xa0001b9c) at 
Python/bltinmodule.c:1631
#3  0x000911b8 in PyEval_EvalFrame (f=0x1904010) at Python/ceval.c:3558
#4  0x00093480 in PyEval_EvalCodeEx (co=0x78a760, globals=0x14, locals=0x0, 
args=0x18fdd74, argcount=3, kws=0x18fdd80, kwcount=0, defs=0x11fb44c, 
defcount=2, closure=0x0) at Python/ceval.c:2736
#5  0x000913d4 in PyEval_EvalFrame (f=0x18fdc10) at Python/ceval.c:3651
#6  0x00093480 in PyEval_EvalCodeEx (co=0x78a3e0, globals=0x14, locals=0x0, 
args=0x1801d64, argcount=2, kws=0x1801d6c, kwcount=0, defs=0x11fa13c, 
defcount=1, closure=0x0) at Python/ceval.c:2736
#7  0x000913d4 in PyEval_EvalFrame (f=0x1801c10) at Python/ceval.c:3651
#8  0x00093480 in PyEval_EvalCodeEx (co=0x78a2a0, globals=0x14, locals=0x0, 
args=0x627028, argcount=2, kws=0x627030, kwcount=0, defs=0x11fa11c, defcount=1, 
closure=0x0) at Python/ceval.c:2736
#9  0x000913d4 in PyEval_EvalFrame (f=0x626ed0) at Python/ceval.c:3651
#10 0x00093480 in PyEval_EvalCodeEx (co=0x754520, globals=0x14, locals=0x0, 
args=0x627028, argcount=1, kws=0x601390, kwcount=0, defs=0x11fb4ec, defcount=2, 
closure=0x0) at Python/ceval.c:2736
#11 0x000913d4 in PyEval_EvalFrame (f=0x601240) at Python/ceval.c:3651
#12 0x00093480 in PyEval_EvalCodeEx (co=0x37b820, globals=0x14, locals=0x0, 
args=0x0, argcount=0, kws=0x0, kwcount=0, defs=0x0, defcount=0, closure=0x0) at 
Python/ceval.c:2736
#13 0x00093610 in PyEval_EvalCode (co=0x0, globals=0x14, locals=0x14800000) at 
Python/ceval.c:484
#14 0x0000db54 in PyRun_FileExFlags (fp=0xa000db34, filename=0xbffff33e 
"/sw/bin/ipython2.4", start=20, globals=0x34ba50, locals=0x34ba50, closeit=1, 
flags=0x37b820) at Python/pythonrun.c:1265
#15 0x0000defc in PyRun_SimpleFileExFlags (fp=0xa000db34, filename=0xbffff33e 
"/sw/bin/ipython2.4", closeit=1, flags=0xbffff14c) at Python/pythonrun.c:860
#16 0x000067e4 in Py_Main (argc=-1073745588, argv=0x80000000) at 
Modules/main.c:484
#17 0x00001e48 in _start (argc=2, argv=0xbffff254, envp=0xbffff260) at 
/SourceCache/Csu/Csu-58/crt.c:272
#18 0x00001cf0 in start ()