On Dec 5, 2008, at 3:22 AM, Ralf Schuchardt wrote:
Am 05.12.2008 um 01:41 schrieb Gary Teter:
Wow. I got misled by my logging. Turns out it's perfectly fine for
__originalSnapshot to be null before objectWillChange is called,
because the first time it's called it sets the __originalSnapshot
>before< the new value is set. Further changes to the object don't
set the __originalSnapshot.
So it turns out that the problem is that somehow objectWillChange
is not getting called until >after< the change has been made.
Here's what it should look like:
[EMAIL PROTECTED] lock()
going to setServiceRate() - [2223, UPS Mail Innovations Bound
Printed Matter, $5.36 for 64 oz, zone 5 (min BPM 50%)]
beginning willChange() - Order # 664975
objectWillChange: Order # 664975, created 08/25/06 03:03:44 PM 1
items for subtotal $59.95
snapshot() - returning: { ...omitted... } <-- here's where
__originalSnapshot gets set
done willChange() - Order # 664975
beginning willChange() - Order # 664975
done willChange() - Order # 664975
done setServiceRate() - [2223, UPS Mail Innovations Bound Printed
Matter, $5.36 for 64 oz, zone 5 (min BPM 50%)]
And here's what it looks like when it's borked:
[EMAIL PROTECTED] lock()
going to setServiceRate() - [5, UPS Ground for 2400 oz, United
States]
beginning willChange() - Order # 664975
done willChange() - Order # 664975
beginning willChange() - Order # 664975
done willChange() - Order # 664975
done setServiceRate() - [5, UPS Ground for 2400 oz, United States]
Note that the serviceRate has been completely set by this point,
and objectWillChange has not yet been called. (It gets called
later. Now I get to figure out why
EOObserverCenter.notifyObserversObjectWillChange() apparently
isn't doing its job...
It might well be another EOF bug (or a consequence of the bug Chuck
talked about).
EOObserverCenter stores the last changed object per thread, so it
will not repeatedly send notifications for the same object.
This information is normally reset at certain points, but sometimes
it's missed.
As a result you may see sporadic failures to recognize changes in
an EO when the same worker thread is changing the same object.
A workaround may be to call
"EOObserverCenter.notifyObserversObjectWillChange(null)" at
strategic places like in Application.dispatchRequest().
(But I believe the real culprit is the EC loosing its information
about changed objects, otherwise it shouldn't be necessary to tell
the EC about changes in an EO again ...)
Ralf
That's what I suspected, so I added a call to
notifyObserversObjectWillChange(null) to a method that responds to
the EditingContextDidSaveChanges notification, figuring that's the
best place to put it. But the borking is still there. I also added
logging to see if the observerNotificationSuppressCount was non-zero
during OrderObject's willChange (it's zero), and to display the
observersForObject for the OrderObject in case somehow its ec was not
on the list (it is).
As I understand EOObserverCenter the only thing left is that the
observer center's last changed object is being set somehow behind my
back in between my setting it to null and my attempt to set the
serviceRate relationship. But how and why is eluding me right now:
[EMAIL PROTECTED] _clearOriginalSnapshotAndInitializeRec
() - OrderLineItem 1302722
_editingContextDidSaveChanges - notifyObserversObjectWillChange(null)
[EMAIL PROTECTED] saveChanges()
_editingContextDidSaveChanges - notifyObserversObjectWillChange(null)
[EMAIL PROTECTED] unlock()
[EMAIL PROTECTED] tryLock()
[EMAIL PROTECTED] lock()
[EMAIL PROTECTED] processRecentChanges()
[EMAIL PROTECTED] unlock()
<end of previous request>
[2008-12-04 18:42:46 PST] <WorkerThread8> <127.0.0.1> "POST /cgi-bin/
WebObjects/Store.woa/1/wo/TdoyaGbiVbMqgXYbawJFpw/
93.2.3.1.0.2.1.35.3.1.1.1.1.2.1.5.3.0.3.1 HTTP/1.1" Mozilla/5.0
(Macintosh; U; Intel Mac OS X 10_4_11; en) AppleWebKit/525.27.1
(KHTML, like Gecko) Version/3.2.1 Safari/525.27.1
[EMAIL PROTECTED] lock()
going to setServiceRate() - [5, UPS Ground for 2400 oz, United States]
beginning willChange() - Order # 664975,
observerNotificationSuppressCount: 0
beginning willChange() - Order # 664975, observersForObject:
([EMAIL PROTECTED])
done willChange() - Order # 664975, observerNotificationSuppressCount: 0
done willChange() - Order # 664975, observersForObject:
([EMAIL PROTECTED])
beginning willChange() - Order # 664975,
observerNotificationSuppressCount: 0
beginning willChange() - Order # 664975, observersForObject:
([EMAIL PROTECTED])
done willChange() - Order # 664975, observerNotificationSuppressCount: 0
done willChange() - Order # 664975, observersForObject:
([EMAIL PROTECTED])
done setServiceRate() - [5, UPS Ground for 2400 oz, United States]
Anybody know the best way to install my own replacement
EOObserverCenter so I can see what's going on? Or a way to set
breakpoints in code that's not mine?
--
The Ent visualization project:
http://wirehose.com/research/entvisualization
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