YT-20547: TIncarnationId is strongly typed

First commit

2 files changed, 41 insertions, 1 deletions

diff --git a/library/cpp/yt/misc/wrapper_traits-inl.h b/library/cpp/yt/misc/wrapper_traits-inl.h
index 88d1af5945d..7ab7699641e 100644
--- a/library/cpp/yt/misc/wrapper_traits-inl.h
+++ b/library/cpp/yt/misc/wrapper_traits-inl.h
@@ -78,6 +78,32 @@ constexpr bool TWrapperTraits<T>::RecursiveHasValue(const T& wrapper) noexcept
     }
 }
 
+template <class T>
+    requires std::is_object_v<T>
+template <class U>
+constexpr T TWrapperTraits<T>::Wrap(U&& unwrapped) noexcept
+{
+    static_assert(std::same_as<std::remove_cvref_t<U>, TUnwrapped>);
+
+    return T(std::forward<U>(unwrapped));
+}
+
+template <class T>
+    requires std::is_object_v<T>
+template <class U>
+constexpr T TWrapperTraits<T>::RecursiveWrap(U&& unwrapped) noexcept
+{
+    using TTraits = TWrapperTraits<T>;
+    using TInnerTraits = TWrapperTraits<typename TTraits::TUnwrapped>;
+
+    if constexpr (CNonTrivialWrapper<TUnwrapped>) {
+        return TTraits::Wrap(TInnerTraits::RecursiveWrap(std::forward<U>(unwrapped)));
+    } else {
+        //! U == TUnwrapped.
+        return TTraits::Wrap(std::forward<U>(unwrapped));
+    }
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 
 //! Some standard library specializations
@@ -98,7 +124,7 @@ struct TBasicWrapperTraits<std::optional<T>>
 
     template <class U>
         requires std::same_as<std::remove_cvref_t<U>, std::optional<T>>
-    static decltype(auto) Unwrap(U&& optional)
+    static constexpr decltype(auto) Unwrap(U&& optional)
     {
         return *std::forward<U>(optional);
     }
diff --git a/library/cpp/yt/misc/wrapper_traits.h b/library/cpp/yt/misc/wrapper_traits.h
index 61a97b8ea44..8a6d5814199 100644
--- a/library/cpp/yt/misc/wrapper_traits.h
+++ b/library/cpp/yt/misc/wrapper_traits.h
@@ -1,5 +1,6 @@
 #pragma once
 
+#include <concepts>
 #include <utility>
 
 namespace NYT {
@@ -49,6 +50,19 @@ public:
     static constexpr decltype(auto) RecursiveUnwrap(U&& wrapper);
 
     using TRecursiveUnwrapped = std::remove_cvref_t<decltype(TWrapperTraits<T>::RecursiveUnwrap(std::declval<T>()))>;
+
+    //! Unfortunatelly, clang is incapable of processing associated constraints if they depend
+    //! on class information (e.g. aliases and static varibles) and written out-of-line.
+
+    //! TODO(arkady-e1ppa): Add proper constraints when clang supports them:
+    //! Wrap: std::same_as<std::remove_cvref_t<U>, TUnwrapped>
+    //! RecursiveWrap: std::same_as<std::remove_cvref_t<U>, TRecursiveUnwrapped>
+    //! Proper constructible_from checks? Easy for wrap, hard for recursive wrap.
+    template <class U>
+    static constexpr T Wrap(U&& unwrapped) noexcept;
+
+    template <class U>
+    static constexpr T RecursiveWrap(U&& unwrapped) noexcept;
 };
 
 ////////////////////////////////////////////////////////////////////////////////