[issue1565525] tracebacks eat up memory by holding references to locals and globals when they are not wanted

[Greg Hazel]

Greg Hazel <ghazel at users.sourceforge.net> added the comment:

The objects I do want in the traceback are the objects necessary to print a traceback, but not the locals and globals of each frame.

For example:

def bar():
  x = "stuff"
  raise Exception("example!")
bar()

prints: 
Traceback (most recent call last):
  Line 4, in <module>
    bar()
  Line 3, in bar
    raise Exception("example!")
Exception: example!

There is no reason in that example to have a reference to "x" in the traceback, since it's not used in the output. This becomes important when I try to save a reference to the traceback object and raise it later:

import sys
def bar():
  x = "stuff"
  raise Exception("example!")
try:
  bar()
except:
  exc_info = sys.exc_info()
def foo(e):
  raise e[0], e[1], e[2]
# sometime possibly much later...
foo(exc_info)

Traceback (most recent call last):
  Line 12, in <module>
    foo(exc_info)
  Line 6, in <module>
    bar()
  Line 4, in bar
    raise Exception("example!")
Exception: example!


During that "sometime possibly much later..." comment, a reference to "x" is held, when it will not be used in printing the traceback later. So, I would not like to keep a reference to "x", and currently there is no way to do that without also dropping a reference to the data needed to print the traceback.

----------

_______________________________________
Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue1565525>
_______________________________________