[Development] Source break policy for function overloads

Thiago Macieira thiago.macieira at intel.com
Wed Jul 13 18:47:28 CEST 2016

Em quarta-feira, 13 de julho de 2016, às 10:44:13 PDT, Alexander Blasche 
> Hi,
> Yesterday, I stumbled over a break in QtSerialBus due to the addition of new
> QTimer::setInterval(..) overloads in qtbase/dev. This was introduced by
> https://codereview.qt-project.org/#/c/160889/
> Unfortunately this has the undesirable side effect that lines like:
> q->connect(q, &QModbusClient::timeoutChanged, element.timer.data(),
> &QTimer::setInterval);
> do not compile anymore. The function pointer to setInterval() becomes
> ambiguous. While the fix (https://codereview.qt-project.org/#/c/165034/)
> was not difficult once you know what is happening this can hit every
> customer and basically reduces the source compatibility promise into
> absurdity.
> While talking to several devs in the office I could not find a congruent
> opinion on this issue. Do we or even can we care? Do we have a policy?

We do have this policy since 5.0 that we have to be careful about overloads 
due to the connect syntax. The breakage was accidental and not intended.

I did intend to add overloads, as they're nice to use, I just hadn't 
considered the consequences.

Thiago Macieira - thiago.macieira (AT) intel.com
  Software Architect - Intel Open Source Technology Center

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