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Bug 353303

Summary: RWOLockManager.unlock(CONTEXT) gives ConcurrentModEx
Product: [Modeling] EMF Reporter: Caspar D. <caspar_d>
Component: cdo.coreAssignee: Caspar D. <caspar_d>
Status: CLOSED FIXED QA Contact: Eike Stepper <stepper>
Severity: normal    
Priority: P3 CC: saulius.tvarijonas
Version: 4.1Flags: stepper: review+
Target Milestone: ---   
Hardware: All   
OS: All   
Whiteboard:
Attachments:
Description Flags
Patch v1
none
Patch v2
none
Patch v3 (left-over tests removed) none

Description Caspar D. CLA 2011-07-28 07:12:24 EDT 
Unlocking all locks for a given context, i.e. calling 
RWOLockManager.unlock(CONTEXT context), causes ConcurrendModEx,
due to the removal of lockStates while the set of lockStates
for a given context is being iterated over. (The actual
removal happens in #removeLockFromContext.)

No test case was ever written for this scenario. Not sure if
the old RWLockManager did it right. Doesn't matter now, will
provide a fix + testcase for the RWOLockManager momentarily.
Comment 1 Caspar D. CLA 2011-07-28 07:14:08 EDT 
Created attachment 200519 [details]
Patch v1
Comment 2 Caspar D. CLA 2011-07-28 07:22:00 EDT 
Created attachment 200521 [details]
Patch v2

v2 of the patch renames the maps and a method involved with updating
the contextToLockStates map.

I know you (Eike) renamed the method before, but I really believe the
name 'removeLockFromContext' is deceiving. First, what's being removed
is a LockState object, which is a combination of locks, not a single
lock. And second, it's not being removed from a context; rather, it's
being removed from the set of all lockStates that a given context is
involved in. I added JavaDocs to the method, to this effect.

(Functionally patch v2 is the same as v1.)
Comment 3 Caspar D. CLA 2011-07-28 07:26:45 EDT 
PS. I recommend looking at patch v1 first, because it shows how minimal
the fix is.
Comment 4 Eike Stepper CLA 2011-07-28 07:54:24 EDT 
Created attachment 200524 [details]
Patch v3 (left-over tests removed)
Comment 5 Caspar D. CLA 2011-07-28 08:10:48 EDT 
Committed revision 8839.
Comment 6 Eike Stepper CLA 2012-09-21 07:19:00 EDT 
Closing.