[Development] Unnecessary ambiguity in Qt documentation about reentrancy and safety of const methods.

[Giuseppe D'Angelo]

On 18/07/2026 19:41, Thiago Macieira wrote:
> If the class is using a smart pointer for the Private, the smart pointer will
> propagate the constness of the public function and it will be easy to notice
> where we violate by way of a const_cast. Older classes often use raw pointers,
> which don't propagate const, and then we may perform non-const operations,
> intentionally or not.

For QMap I introduced QESDPV2 precisely because I wanted deep constness. 
Neither QESDP nor the standard library smart pointers propagate, and 
those are landmines. We should likely also introduce a private 
propagate_const if someone really needs a raw pointer for whatever reason.

This is also documented as THICK.8 in
https://codereview.qt-project.org/c/meta/quips/+/321050

(I also ported uic to generate propagate_const<> around the QWidget* 
data members in the ui class, catching many logical constness bugs in 
some projects.)

My 2 c,
-- 
Giuseppe D'Angelo | giuseppe.dangelo at kdab.com | Senior Software Engineer
KDAB (France) S.A.S., a KDAB Group company
Tel. France +33 (0)4 90 84 08 53, http://www.kdab.com
KDAB - Trusted Software Excellence
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