Hey, Nick. Discontent is the father of invention.
Revision 2098 works around test failures when POE::Wheel::ReadLine's
DESTROY calls $poe_kernel->select() and state() outside the proper
session context. Certain asserts turn this behavior into hard, fatal
errors, and POE's tests usually run with all asserts turned on.
The problem's source is the dynamic pending functions in
POE::Wheel::ReadLine. They create closures for $self. The object
can't destruct until the functions do, and the functions stored in
SELF_PENDING and SELF_PENDING_FN won't until the object does. Perl
eventually breaks up this group hug during global destruction just
prior to exiting.
Revision 2098 is a complete mistake. I shouldn't have patched over a
memory leak, but I justified it by considering that
POE::Wheel::ReadLine object lifetimes usually match the entire
program using it. Few people would notice it leaking because. I
might have gotten away with it, too, if I had remembered to restore
the terminal.
I'd like to reverse revision 2098. It may be as easy as ensuring
that the SELF_PENDING and SELF_PENDING_FN members are cleaned up when
they're not needed. The new ReadLine test should stop blowing up
when it's fixed.
--
Rocco Caputo - [EMAIL PROTECTED]
On Sep 19, 2006, at 07:48, Nick Williams wrote:
I now have a new problem (don't I always ;-).
ReadLine has a modification that I didn't spot earlier (due to our
inability to use the last few releases) that doesn't make sense to
me. The change labelled r2098 (which went into 0.37, I believe)
does this:
2006-09-05 01:41:11 (r2098) by rcaputo; poe/lib/POE/Wheel/
ReadLine.pm M
A cheezy hack to avoid destroying Wheel::ReadLine instances from
within POE::Kernel's space. A proper fix would be to somehow break
this wheel's circular references to $self so that DESTROY is
triggered immediately when the user destroys the objects' last
references.
I really really don't understand this. The hack is within DESTROY
(i.e. it's within the code that's called when the wheel is
evaporating: by definition there are no more references). The hack
says if we're evaporating and our parent session has already left
the building, then we will not do proper DESTROY semantics but will
instead return. An important result of this is that we won't bother
resetting the terminal mode back to normal. Which means that quite
often after using this module, the terminal will be screwed up.
This isn't good. A quick hack fix would be to always restore the
terminal state before we hit the conditional return. But then it
leads me into where I don't understand: why would we not want to do
all of the cleanup? Even if the parent is poe_kernel (i.e. our real
session parent has already departed), we can still do cleanup.
We're in the DESTROY handler! Does it hurt to do any of that
cleanup? Is the comment saying something else? I don't understand
the reasoning behind this....
Nick
Rocco Caputo wrote:
You have a few hours to perhaps a day or two to prepare yourself
for the onslaught of goodness encapsulated in this release.
Perhaps most significantly, the two changes you've been waiting
for all week (if not longer):
+ The sig() reference count has been removed. There will be much
rejoicing, and probably some gnashing of teeth.
+ sig_child($pid, $event) was introduced. It waits for an
explicit process ID. It holds a session reference count. It
automatically clears after the specified process has been reaped
and the event has been delivered.
But that's not all. Other people were busy improving POE while I
was distracted by signals fixes. Give a big shout out to:
+ Apocalypse made alias_resolve() failures non-fatal when certain
assertions are enabled. Rob Bloodgood reported this problem, and
persisted in making sure it was fixed.
+ Vanilla Perl test failures were worked around. That
distribution is highly experimental. Its developers don't
recommend its use. And it isn't bundled with Win32::Console,
needed by the Wheel::Run tests. So those tests are skipped if
that module isn't installed.
+ Martijn Van Beers documented some hook methods in POE::Session,
improving POE's kwalitee and passing the features on to you!
+ Matt Sickler applied a doc patch for TRACE_STATISTICS, submitted
by Joel Bernsein.
And some 0.37 test failures were fixed. And probably other stuff
I forgot. That's okay, though. There's a CHANGES file inside
the tarball, and it'll be more than happy to explain everything
in much greater detail.
