Bug 354700

Description Chris Fairhall 2011-08-14 00:07:42 EDT

Build Identifier: 1.5.0.20110720-0846

I've started using ProgressMonitorDialogs to give user feedback to long running operations.
This was going great until we started running out of memory.

I've found that if a user closes their browser while a progress dialog is open its ModalContextThread will never terminate. It is stuck in a display.syncExec.


It looks like a syncExec call will never return after the display is disposed of. The caller sits in a while(!lock.done()) lock.wait()
Interrupting the thread won't even break it out as the exception is caught and not dealt with until after lock.done() == true

The ModalContextThread holds references to the Display (and from there, all widgets, etc...) and UIThread, stopping them from being garbage collected as being a Thread it is a GC root.

It is also impossible to hack around this as the only reference left to the RunnableLock after the Display is disposed is on a stack frame inside a method.


Currently the only fix I can think of is setting a Throwable to all the current runnable locks and notifying them when a display is disposed. That would propagate the throwable to the caller of syncExec (wrapped in an SWTException)


Reproducible: Always

Steps to Reproduce:
1. Create a ModalContext via new ProgressMonitorDialog(...)
2. Dispose of Display before the ModalContextThread finishes
3. ModalContextThread will never terminate