[pywin32-bugs] [ pywin32-Bugs-874096 ] Race condition with genpy.py and stdout

[SourceForge.net <no...@so...>]

Bugs item #874096, was opened at 2004-01-10 08:56
Message generated for change (Comment added) made by mhammond
You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=551954&aid=874096&group_id=78018

Category: com
Group: None
Status: Open
Resolution: None
Priority: 5
Submitted By: David Boreham (dboreham)
Assigned to: Nobody/Anonymous (nobody)
Summary: Race condition with genpy.py and stdout

Initial Comment:

I've been investigating a problem for a client of mine
where the symptoms were that a generated python
file in the ...\win32com\gen_py directory had become
corrupted. It looked mostly ok, but contained one
line of text which was not Python. I tracked that string
down to another part of the application, completely
unrelated.

Upon investigation I believe that the cause is this
code in genpy.py:

  def generate(self, file, is_for_demand = 0):
    if is_for_demand:
      self.generate_type = GEN_DEMAND_BASE
    else:
      self.generate_type = GEN_FULL
    self.file = file
    oldOut = sys.stdout
    sys.stdout = file
    try:
      self.do_generate()
    finally:
      sys.stdout = oldOut
      self.file = None
      self.progress.Finished()

It's redirecting stdout for the generated python file.
In the application this happens underneath a call
to gencache.EnsureModule().
Unfortunately the application is concurrently executing 
another thread which is also writing to stdout.

The result is that the two sets of output are 
intermingled.

I guess that it would be possible to refactor the
code in genpy.py such that it outputs to a file
rather than to stdout (the file could be stdout
for cases where the code is run as a standalone
utility).

I see the checkin comment for version 1.30
suggests that this is a known problem:

>Also started a move to "print >>" for the generation.

Thanks.



----------------------------------------------------------------------

>Comment By: Mark Hammond (mhammond)
Date: 2004-04-07 15:26

Message:
Logged In: YES 
user_id=14198

Yes, this could happen :)  I'd love patches to address this.

----------------------------------------------------------------------

You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=551954&aid=874096&group_id=78018