Amends 32edae5e26, after which we keep a
copy of the restored state if the state couldn't be applied yet. Since
making a copy of the entire state results in multiple copies of layout
item pointers, we might end up with dangling pointers if the layout
structure is modified while we keep the copy. This can happen if methods
such as tabifyDockWidgets or splitDockWidget get called; e.g. tabifying
dock widgets will destroy the layout items that were added for them.
Unfortunately, the layout items do not have a pointer back to the layout
they live in, and the items in the stored state might not yet live in a
layout anyway. So we cannot remove the items from their layout in a
QDockWidgetItem destructor implementation.
Instead, we have to forget the stored state. Add a helper function that
writes the stored state back to the actual state, and deletes the stored
state afterwards. Call this function when the layout might get modified
programmatically.
Add a test case that reproduces the crash without the fix, and passes
with the patch.
Fixes: QTBUG-120025
Pick-to: 6.7 6.6 6.5
Change-Id: I8f7e886f3c4ac38e25f9b8bc194eea0833e5974f
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Axel Spoerl <axel.spoerl@qt.io>
9ea9e2476d