auidemo crashes when undocking toolbars

[ksinger2]

auidemo crashes when undocking toolbars with svn checkout of 58061.
os: vista
msvc9

reason pane.frame is null pointer!

bugfix:
..\..\src\aui\framemanager.cpp
line 3520: wxPoint frame_pos = pane.frame->GetPosition();

replace by:
wxPoint frame_pos(0,0);
if(pane.frame) frame_pos= pane.frame->GetPosition();

[bpetty]

I tried to reproduce this on Windows XP using 2.8.9, SVN 2.8 branch, and SVN trunk (2.9) without success when this was first reported. I figured this was just a Vista issue, and left it for someone with Vista to investigate.

Today, as reported in #10516, this is possibly the same crash supposedly being seen on Windows XP with wxPython 2.8.9.2 and also in the demo. I've now also tried to reproduce this crash using wxPython 2.8.9.2 with Python 2.6, and I still don't see this crash.

Since there's now been two reports of this, and we're just about to release 2.8.10, I've decided to go ahead and commit a blind fix which will likely prevent the crash, but since I can't determine the reason why pane.frame is null, this fix will not likely be the appropriate solution to what could be a different problem altogether, and undocking toolbars in both these cases where it is crashing may still not work (even if the crash is fixed).

I'd appreciate it if you could give a more detailed description of how to reproduce this crash (and include a call stack of the crash), and test my fix in r59107 of the 2.8 branch in SVN.

As described by the reporter, this crash is either in wxAuiManager::OnFloatingPaneMoving() and/or wxAuiManager::OnFloatingPaneMoved(). Both functions should only be called with a valid floating pane which should always have a valid associated frame. So if frame is indeed null, that means we have a problem somewhere else that needs to be fixed. My temporary fix will simply just return from these functions if there isn't a valid frame, but that also means that the floating frame or hint window (if either exist when these functions are being called with an invalid frame) will not be handled correctly.

[biwillia76]

I've been looking at this bug recently, and will make sure the patch applied is valid. Thanks much. -Ben

[byte]

Did you try "http://trac.wxwidgets.org/attachment/ticket/9931/aui.diff" before that fix?
I had the same problem with aui toolbars and found typo in AUI (+workaround to fix that typo!).
Patch fixes this (remove unneeded comments if all ok).

[net147]

Backtrace of crash.

[net147]

I've attached a backtrace of the crash on 2.9 SVN.

[net147]

Fix for crash when moving floating pane.

[net147]

This issue was fixed in the 2.8 branch by r59107 but has not been applied to 2.9 SVN. I've attached a patch to fix this in 2.9 SVN.

[net147]

I suspect that OnPaneMoving or OnPaneMoved is being called somewhere between when the frame is created and when p.frame is set to the instance of the frame. I can consistently reproduce this crash on one of my development systems so i'll look into this and report back what I find.

[net147]

I have found why this crash occurs. Changeset r54905 introduced a call inside wxAuiFloatingFrame::SetPaneWindow to SetWindowStyleFlag which sometimes causes a movement event to be triggered before p.frame is set. Undocking and docking toolbars with r59107 applied seems to work fine for this case.

[biwillia76]

Wow. Great job debugging this. This information will form the basis of the correct patch. Thanks much.

[vadz]

Resetting 2.9.0 milestone as it's too late for it

[net147]

Would it not be a good idea to apply the fix in r59107 to trunk as well so that it doesn't crash until we find a more proper fix (if any) for this?

[biwillia76]

Done. Thanks for pointing this out.

[net147]

Replying to biwillia76:

Done. Thanks for pointing this out.

Did you find any clues for a correct patch for this or is the current one sufficient?

[net147]

Would it be appropriate to apply the fix in r59107 to the 2.9.0 branch as well since it is still in release candidate status?

[net147]

I don't see why 2.8 SVN and trunk have the fix applied but 2.9.0 branch doesn't. I think it should be applied so that 2.9.0 shouldn't crash out of the box when people use AUI toolbars on some systems...

[BIW]

(In [60628]) fix from r59107 - aui toolbar crash fixed (fixes #10371)