Can the same checks be implemented in clang-tidy instead of having yet another tool? clang-tidy now has boost specific checks so maybe they would also accept a Qt specific module in there.
On Sun, 11 Sep 2016 at 03:29 Sergio Martins <sergio.mart...@kdab.com> wrote: > Hi, > > > I've been developing a Qt oriented clang compiler plugin called clazy [1]. > > It has about 50 custom checks/warnings for common Qt and C++ mistakes. > I would like to propose clazy to be used to sanitize API of new Qt > modules. Of > course, only a few of the 50 checks are relevant to API, so I will only > talk > about those. > > > ** Checks that can find bugs ** > > > * clazy-copyable-polymorphic > > polymorphic copyable classes are usually vulnerable to slicing [2] > The cases I found were either real bugs or easily fixable by adding > Q_DISABLE_COPY. > > > > * clazy-rule-of-two-soft > > Finds when you're calling the compiler generated copy-ctor of a class that > has > a user-defined assign operator (and vice-versa). > You'll want to write both, or none. I've found many bugs where one of them > was > missing (where the copy-ctor didn't have the same behavior as the assign- > operator). > > In most cases you can simply remove the user defined methods and let the > compiler generate them. > > > > > * clazy-rule-of-three > > Either implement all 3 dtor, copy-ctor and assign-op or none of them. > > This is my favorite as it finds many bugs which are easy to fix. > > It's very common to have a class that is holding a resource and frees it in > the DTOR, but if that class gets copied then two DTORs might run, freeing > the > resource twice, which might crash or misbehave the app. > > See for example https://codereview.qt-project.org/#/c/151488/ , > QBasicTimer is > copyable, but when a copy is destroyed it stops both timers. > > Also common is copying a class that has a d-pointer and getting a crash > when > both DTORs are run because you forgot the copy-ctor and assign-op. > > So either implement the copy-ctor and assign-op too, or use > Q_DISABLE_COPY, or > in the majority of cases, just remove your DTOR if it doesn't do any work. > > > > * mutable-container-key > > QMap or QHash having a key that can be modified by external factors (like > QPointer) > > > > > > ** Nice to haves (don't find real bugs but are related to performance) ** > > > * clazy-function-args-by-ref > > Pass big or non-trivial types (so copy-ctor and dtor don't get called) by > const-ref > > > > * clazy-missing-typeinfo > > Types used in containers but missing a Q_DECLARE_TYPEINFO > > > > * clazy-qenums: > > Use Q_ENUM instead of Q_ENUMS > > > * clazy-missing-qobject-macro > > missing a Q_OBJECT macro > > > > ** Debatable ** > > * clazy-function-args-by-value > Pass small and trivial types by value > > > Thanks for reading. > > > [1] https://github.com/KDE/clazy > [2] https://en.wikipedia.org/wiki/Object_slicing > > > > Regards, > -- > Sérgio Martins | sergio.mart...@kdab.com | Senior Software Engineer > Klarälvdalens Datakonsult AB, a KDAB Group company > Tel: Sweden (HQ) +46-563-540090, USA +1-866-777-KDAB(5322) > KDAB - The Qt Experts > _______________________________________________ > Development mailing list > Development@qt-project.org > http://lists.qt-project.org/mailman/listinfo/development >
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