Marc Mutz 101427957b tst_QGraphicsItem: check that qgraphicsitem_cast casts correctly
GCC, with ubsan and optimization enabled, issues -Warray-bounds for
the cast from &polygonItem to QGraphicsTextItem*, because the latter
is-a QObject and the former is not, so the cast has to adjust the
pointer value to correct for the fact that QGraphicsItem is not the
first base class of QGraphicsTextItem:

  qgraphicsitem.h:973:56: warning: array subscript -1 is outside array bounds of ‘QGraphicsPolygonItem [1]’ [-Warray-bounds]
    973 |         || (item && int(Item::Type) == item->type()) ? static_cast<T>(item) : nullptr;
        |                                                        ^~~~~~~~~~~~~~~~~~~~
  tst_qgraphicsitem.cpp:3193:26: note: while referencing ‘polygonItem’

Check the implementation is correct in this respect by not just
checking for nullptr or non-nullptr, but checking that the result
matches what dynamic_cast produces.

We can assume dynamic_cast works on QGraphicsItems because QPA is
using dynamic_cast, so both QtGui and QtWidgets need to have been
compiled with RTTI enabled.

This doesn't eliminate the GCC warning, but confirms that it is a
False Positive.

Pick-to: 6.9 6.8 6.5
Change-Id: Ifc262cb6e715e8e68c180855adc2467960da89a1
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
2025-04-05 17:24:45 +00:00
..
2024-11-05 14:36:16 +01:00
2023-04-13 18:30:58 +02:00

This directory contains autotests and benchmarks based on Qt Test. In order
to run the autotests reliably, you need to configure a desktop to match the
test environment that these tests are written for.

Linux X11:

   * The user must be logged in to an active desktop; you can't run the
     autotests without a valid DISPLAY that allows X11 connections.

   * The tests are run against a KDE3 or KDE4 desktop.

   * Window manager uses "click to focus", and not "focus follows mouse". Many
     tests move the mouse cursor around and expect this to not affect focus
     and activation.

   * Disable "click to activate", i.e., when a window is opened, the window
     manager should automatically activate it (give it input focus) and not
     wait for the user to click the window.