Glyph Lefkowitz wrote: […]
Agreed. I've seen this behavior crop up shocking close to the top of profiles for Calendar Server as well, so I'm very glad to hear you've undertaken this work. The current default is almost certainly wrong; the only code which has practically ever used it was the HTML traceback stuff, which most serious users disable for security reasons anyway.
Good to know we're not the only ones :) The fact that it speeds up 'trial twisted' by ~10-15% is a nice bonus too!
Debugging is kind of a process-global thing, most of the time. I think maybe we should have 'twisted.python.debug' which is the main thing that all these features use, and then a setDebugging for each system (Failure, Deferred, reactor; and ideally, eventually stuff like web, mail, conch too) to turn on these expensive-but-occasionally-worthwhile features.
A similar scheme has worked well for bzrlib. +1
But I'd be happy if this change did _nothing_ but make Failure simply default to not capturing globals and locals, and add a flag to explicitly request this behavior. Like you say: the information is always captured but almost never used.
That's fine with me! I'll update the patch to add captureVars=False to Failure.__init__ instead of what it currently does, and happily leave defer.py unmodified from trunk. Thanks for the feedback, -Andrew.