Make explicit that we expect co-ordinates to be finite

The various spatial-vector, line, point, region and margin types have
all long taken for granted that their co-ordinates are finite and, in
particular, not NaN. Make this expectation explicit in the
documentation. Added assertions where (chiefly) noexcept and (where
the assertion would be a simple qIsFinite() call) constexpr didn't
preclude doing so. Also assert against zero divisors that would lead
to non-finite results.

Make minor clean-ups to docs in the process. QMarginsF had several
methods whose declaration, definition and docs weren't consistent in
their parameter names.

Task-number: QTBUG-89010
Change-Id: I601a830959d13a73dcb17ce31a1202a1486c8f7f
Reviewed-by: Laszlo Agocs <laszlo.agocs@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>

1 files changed, 5 insertions, 1 deletions

diff --git a/src/corelib/tools/qpoint.h b/src/corelib/tools/qpoint.h
index 118d837d69..b886ce3801 100644
--- a/src/corelib/tools/qpoint.h
+++ b/src/corelib/tools/qpoint.h
@@ -295,7 +295,10 @@ public:
     friend constexpr inline QPointF operator-(const QPointF &p)
     { return QPointF(-p.xp, -p.yp); }
     friend constexpr inline QPointF operator/(const QPointF &p, qreal divisor)
-    { return QPointF(p.xp / divisor, p.yp / divisor); }
+    {
+        Q_ASSERT(divisor < 0 || divisor > 0);
+        return QPointF(p.xp / divisor, p.yp / divisor);
+    }
 
     constexpr QPoint toPoint() const;
 
@@ -406,6 +409,7 @@ constexpr inline QPointF &QPointF::operator*=(qreal c)
 
 constexpr inline QPointF &QPointF::operator/=(qreal divisor)
 {
+    Q_ASSERT(divisor > 0 || divisor < 0);
     xp /= divisor;
     yp /= divisor;
     return *this;