[cpp-qt-client] New makeOperationsVirtual option

[limentas]

This PR implements new makeOperationsVirtual option for cpp-qt-client generator. If this option has true value then generated operations become virtual. This allows to easily mock up generated code and unit test the code which uses generated classes. You can find example of generated code here as a diff. On the left side the code how it looks like before the changes or with default value of the new option. And on the right side the code how it looks like after the changes and with the option set to true.

Fix #19512

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  @ravinikam @stkrwork @etherealjoy @MartinDelille @muttleyxd

[muttleyxd]

Looks good, I wonder if it shouldn't be set to true by default. Both ways are fine for me though.

[limentas]

Thanks for your review.
Talking about making the option true by default. My point was to not change current behavior. But I don't see any harm if it is on by default. Since *Api class already has QObject as a parent it already has virtual table. I also don't see a code that can be broken with this change as well. But maybe I'm missing something.

[MartinDelille]

Why not just adding the virtual keyword and without the option ?

[limentas]

My intention is to not break something. Although I don't foreseen problems I may miss something. If you guys think that we can make this behavior default. I'm all for it.

[wing328]

My intention is to not break something. Although I don't foreseen problems I may miss something. If you guys think that we can make this behavior default. I'm all for it.

Thanks for taking consideration into backward compatibility.

Upcoming release allows breaking changes with fallbacks so please set the option to true by default and we will see if any user encounters issues with this enhancement.

[limentas]

@wing328 Thank you for your input. This totally makes sense.
I've made the new parameter true by default.

[wing328]

can you please update the samples (step 3) as well as we should see some changes in the c++ qt petstore client?

[limentas]

can you please update the samples (step 3) as well as we should see some changes in the c++ qt petstore client?

@wing328 Thanks for reminder. It turned out I've made the property true by default in a wrong way. I figured out and fixed the issues.

[MartinDelille]

Happy to see new contributor to the qt cpp generator! 🎉