[New-bugs-announce] [issue8011] traceback tb_lineno example needs correction for Python3

[Michael Newman]

New submission from Michael Newman <michael.b.newman at gmail.com>:

In the second example given in "27.8.1. Traceback Examples" at:
http://docs.python.org/3.1/library/traceback.html
http://docs.python.org/py3k/library/traceback.html
which has the lumberjack:

The last line won't work in Python 3.1 and 3.2:
 print("*** tb_lineno:", traceback.tb_lineno(exceptionTraceback))
because "tb_lineno" is no longer an attribute in the "traceback" module.

# Python 2.6 works fine (because Python2 retains the "tb_lineno" attribute in the "traceback" module):
# Python 2.6.4 (r264:75706, Dec  7 2009, 18:45:15) [GCC 4.4.1] on linux2
*** print_tb:
  File "print_traceback_and_exception.py", line 18, in <module>
    lumberjack()
...
*** format_tb:
['  File "print_traceback_and_exception.py", line 18, in <module>\n    lumberjack()\n', '  File "print_traceback_and_exception.py", line 12, in lumberjack\n    bright_side_of_death()\n', '  File "print_traceback_and_exception.py", line 15, in bright_side_of_death\n    return tuple()[0]\n']
('*** tb_lineno:', 18)

# Broken example using Python 3.1:
# Python 3.1.1 (r311:74480, Feb  7 2010, 16:32:28) [GCC 4.4.1] on linux2
mike at ebx2009:/media/Cruzer/notes/Programming/python3/lib/traceback$ python3.1 print_traceback_and_exception.py
*** print_tb:
  File "print_traceback_and_exception.py", line 18, in <module>
    lumberjack()
...
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
  File "print_traceback_and_exception.py", line 38, in <module>
    print("*** tb_lineno:", traceback.tb_lineno(exceptionTraceback))
AttributeError: 'module' object has no attribute 'tb_lineno'

# Broken example using Python 3.2:
# Python 3.2a0 (py3k:78294, Feb 21 2010, 16:37:29) [GCC 4.4.1] on linux2
mike at ebx2009:/media/Cruzer/notes/Programming/python3/lib/traceback$ python3.2 print_traceback_and_exception.py 
*** print_tb:
  File "print_traceback_and_exception.py", line 18, in <module>
    lumberjack()
...
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
  File "print_traceback_and_exception.py", line 38, in <module>
    print("*** tb_lineno:", traceback.tb_lineno(exceptionTraceback))
AttributeError: 'module' object has no attribute 'tb_lineno'

This can be corrected by changing the last line of the example from:
print("*** tb_lineno:", traceback.tb_lineno(exceptionTraceback))
to:
print("*** tb_lineno:", exceptionTraceback.tb_lineno)

# Using my "rev1" example:

# Python 3.1 now sees the brighter side of life:
mike at ebx2009:/media/Cruzer/notes/Programming/python3/lib/traceback$ python3.1 print_traceback_and_exception_rev1.py 
*** print_tb:
  File "print_traceback_and_exception_rev1.py", line 19, in <module>
    lumberjack()
...
*** format_tb:
['  File "print_traceback_and_exception_rev1.py", line 19, in <module>\n    lumberjack()\n', '  File "print_traceback_and_exception_rev1.py", line 13, in lumberjack\n    bright_side_of_death()\n', '  File "print_traceback_and_exception_rev1.py", line 16, in bright_side_of_death\n    return tuple()[0]\n']
*** tb_lineno: 19

For reference:
"print_traceback_and_exception_rev1.py" = example corrected with Python3. The original line has been commented out in case you want to turn it back on and see the error yourself.

----------
assignee: georg.brandl
components: Documentation
files: print_traceback_and_exception_rev1.py
messages: 100033
nosy: georg.brandl, mnewman
severity: normal
status: open
title: traceback tb_lineno example needs correction for Python3
versions: Python 3.1, Python 3.2
Added file: http://bugs.python.org/file16357/print_traceback_and_exception_rev1.py

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<http://bugs.python.org/issue8011>
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