[[nodiscard]] and KDE coding policy

[Ingo Klöcker]

On Donnerstag, 30. Juli 2026 17:14:44 Mitteleuropäische Sommerzeit David 
Edmundson wrote:
> I'm seeing more and more merge requests using [[nodiscard]] and now
> review comments insisting on others adding [[nodiscard]] to new code.
> 
> I've seen everyone has their own set of rules:
>  - some don't use it
>  - some add it when the return value is important (like opening a file
> having an error)
>  or when the return value has a RAII pattern or requires the caller to
> take over memory ownership
>  - some add it to every getter
> 
> I don't like inconsistency and I don't like repeated discussions on
> merge requests.
> 
> I would like to as a group decide on something and add it to
> https://community.kde.org/Policies/Library_Code_Policy at least for
> new code with a definitive rule that everyone has to follow.
> 
> Whether we change existing code is also up for discussion it's a
> source-incompatible change even though it's binary compatible.

Is it a source-incompatible change (as in it breaks the build of using code)? 
The compiler will throw warnings like in
https://invent.kde.org/pim/kmbox/-/jobs/4766098, but unless you tell the 
compiler to fail on these warnings it seems to be source compatible.

I'd prefer [[nodiscard]] to be used only if the return value really shouldn't 
be ignored.

This is Qt's [[nodiscard]] policy:
https://contribute.qt-project.org/quips/19

Regards,
Ingo
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