[wxCode-users] [ wxcode-Bugs-2342054 ] crash after rename / cell edit

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Bugs item #2342054, was opened at 2008-11-25 08:21
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Category: treelistctrl
Group: None
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: Ronan Chartois (pgriddev)
Assigned to: Otto Wyss (wyo)
Summary: crash after rename / cell edit

Initial Comment:
After several renames, I get either intermittent crashes or failure of
the Edit control to show and work properly.

The bug is due to the usage of a deleted object. Say, we're editing a label and
hit ENTER. In the OnChar handler, the edit control is marked for some
asynchronous deletion, and then m_finished flag is set.


void wxEditTextCtrl::OnChar( wxKeyEvent &event )
{
    //...
    if (event.GetKeyCode() == WXK_RETURN)
    {
        if (!wxPendingDelete.Member(this))
            wxPendingDelete.Append(this);

        m_finished = true;
        // ...
    }
    // ...
}


At some point in time _later_, the destructor is called (because the object has
been pending for deletion), whicn in turn calls CancelEdit. CancelEdit exits
immediately, because m_finished is set. So there's no chance that
m_renameControl of the owner is reset to NULL.


void wxEditTextCtrl::CancelEdit() {
    if (m_finished) return;

    // ...
    if (m_owner) {
        m_owner->OnRenameAccept(true);  // cancelled
        if (m_owner->m_renameControl == this) {
            m_owner->m_renameControl = NULL;
            m_owner->m_editItem = NULL;
        }
        // ...
    }

    // ...
}


In the next EditLabel call, the following code will crash, because
m_renameControl pointer is dangling.


    if (m_renameControl) {
        m_renameControl->CancelEdit();
    }


I patched this bug by moving the "m_owner->m_renameControl = NULL" above the "if
(m_finished) return;" in CancelEdit. The patch works for me but may be wrong in
some way; unfortunately, I don't have time to think it over and test it. So
please fix this major bug as you see fit.



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