[ python-Bugs-875404 ] global stmt causes breakpoints to be ignored

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Bugs item #875404, was opened at 2004-01-12 06:52
Message generated for change (Comment added) made by isandler
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Category: None
Group: None
Status: Open
Resolution: None
Priority: 5
Submitted By: Maciej Kalisiak (mackal)
Assigned to: Nobody/Anonymous (nobody)
Summary: global stmt causes breakpoints to be ignored

Initial Comment:
It seems that having a "global" statement in "main()" 
(perhaps elsewhere too) causes pdb to ignore
breakpoints in the whole application.  See the attached
example small program.

Procedure:
- pdb python_bug.py  # the attached program
- 's', and then 'n' once or twice to make sure prog loaded
- 'break main'
- 'c'

If the "global foo" statement is present, pdb will not
stop at the breakpoint.  If it is commented out (and
"foo = 1" as well, of course), the breakpoint is obeyed.

I'm using
Python 2.3   (from the Debian "sid" distribution)
Tried under Linux 2.2.20, as well as 2.4.*.

Maciej Kalisiak
mac at dgp dot toronto dot edu


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Comment By: Ilya Sandler (isandler)
Date: 2004-08-04 16:26

Message:
Logged In: YES 
user_id=971153

Patch 1003640 should fix this problem


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Comment By: Ilya Sandler (isandler)
Date: 2004-03-10 14:22

Message:
Logged In: YES 
user_id=971153

The same behaviour exists in the CVS version of python

Here is what (I think) happens:

1. When you try to set a break on a function: e.g "b main"
pdb sets a breakpoint not at "def main", but at the next non
comment/non-blank line of code

2. Sample code has "global " as a first
non-comment/non-blank line of code, so that's where pdb sets
the breakpoint

3. But global is a compile-time statement, the line with
global is never reached at run time, so pdb never stops there

Workaround for the original submitter: put any other
executable stmt as the first line of your main(), or set a
bkpt via line number

However, this behaviour is still wrong...The bug could be
probably fixed by adding more logic to pdb.checkline()....

Are there any other compile-time only statements?

I think I could submit a patch for this problem, but does
anyone look at pdb related patches?? My previous pdb patch
#896011 has been sitting in the queue for a month now...




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