QVariant: fix comparisons between strings and integer 0

250ca8d5f8bb3771695ae8eccb8d9b469003d840 changed the qConvertToNumber
to have a std::optional return instead of a boolean out-argument.

In doing so a code path that was supposed to report a failure (string
could not be converted to an integer) accidentally starting reporting
success (and converting the string to 0).

The problem is that the `ok` check from QString::toLongLong was
accidentally dropped in the refactoring; previously the function set
`ok` to false and returned 0, now the function just returns 0.

Instead, amend that return to return nullopt (because the conversion has
failed).

Change-Id: Iaedef5463f3ec500a97bd4c9bbddf977f66df61a
Pick-to: 6.5 6.5.0
Fixes: QTBUG-111867
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
Reviewed-by: Marc Mutz <marc.mutz@qt.io>

0 files changed, 0 insertions, 0 deletions