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feat(util): Add const-propagating wrapper#301

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bnbajwa merged 1 commit intoreactivemarkets:masterfrom
bnbajwa:util
Oct 22, 2025
Merged

feat(util): Add const-propagating wrapper#301
bnbajwa merged 1 commit intoreactivemarkets:masterfrom
bnbajwa:util

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@bnbajwa bnbajwa commented Oct 21, 2025 •
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Can be used with pointers/smart pointers/custom types

Normally, constness isn't propagated to pointer/reference/smart pointer members of a class. This wrapper allows for propagation of constness. e.g.:

class S {
   int* member;
   void f() const { *member = 5; } // compiles OK -- object pointed by `member` can be modified in const method
};

class S2 {
   propagate_const<int*> member;
   void f() const { *member = 5; } // compiler ERROR -- cannot modify object pointed by `member` in const method
};

SDB-9943

@bnbajwa bnbajwa requested a review from a team as a code owner October 21, 2025 14:47
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Summary of Changes

Hello @bnbajwa, I'm Gemini Code Assist1! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request introduces a robust propagate_const utility designed to enhance const-correctness for types that encapsulate pointers or pointer-like objects. By providing a consistent interface for accessing the underlying value while correctly propagating const qualifiers, this feature simplifies the development of safe and predictable APIs for smart pointers, custom wrappers, and raw pointers, ensuring that mutability is managed appropriately across different access patterns.

Highlights

  • New propagate_const Wrapper: Introduces a propagate_const class template that wraps an object and provides get(), operator->(), and operator*() methods, ensuring const propagation to the underlying pointed type.
  • Flexible Underlying Type Detection: Implements a pointed_underlying struct with specializations for types exposing a get() method (like smart pointers), raw pointers, and references, allowing the propagate_const wrapper to correctly identify and interact with the wrapped object.
  • C++20 Pointer Concept: Adds a new C++20 concept Pointer to Concepts.hpp to identify types that are raw pointers, which is utilized by the pointed_underlying mechanism.
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Code Review

This pull request introduces a propagate_const wrapper class that can be used with pointers, smart pointers, and custom types to propagate constness. It also adds a Pointer concept to Concepts.hpp. The code appears well-structured, but there are a few areas that could be improved for correctness and maintainability.

@bnbajwa
feat(util): Add const-propagating wrapper
b947c15 
Can be used with pointers/smart pointers/custom types

SDB-9943
@bnbajwa bnbajwa merged commit bf46c49 into reactivemarkets:master Oct 22, 2025
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@bnbajwa bnbajwa deleted the util branch October 22, 2025 09:30
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@markaylett markaylett markaylett approved these changes

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