YT-21233: Introduce ToAttributeValue cpo which removes dependency of TErrorAttribute from yt/core

Plan:

 1) Remove `IAttributedDictionary` type from the public API. \+

 2) Remove `Set` method from public API in favor of `operator<<=`. \+

 3) Adopt `ConvertTo<T>` (or other name) CPO with proper extension into `NYT::NYson::ConvertTo` from `yt/core`.

 4) Use CPO from (3) to eliminate direct dependency on `yt/core` of `Get/Find` methods from attributes API.

 5) Adopt `ConvertToYsonString` (or other name) CPO with proper extension into `yt/core` customisations.

 6) Use CPO from (5) to eliminate direct dependency on `yt/core` of `TErrorAttribute` ctor.

 7) Swap attributes implementation to the one which doesn’t use `IAttributeDictionary`.

 8) At this point `stripped_error*` can be moved to library/cpp/yt and so can recursively dependant on THROW macro methods `Get/Find/…`.

 9) Adjust CPO’s to work with `std::string` instead of `TYsonString` assuming text format to be used (maybe `TString` for now).

10) Remove dep of `library/cpp/yt/error` on `yson` entirely.

This pr addresses 5-6 steps of plan. Below is a brief explanation of design decisions. We also expressed everything related to key-value code in terms of aliases of `TErrorAttribute` so that later we could make a relatively simple switch to `std::string`. We expect to do steps 7-8 in the next pull request as everything should be ready
commit_hash:de9feca2bd24d823b33d904ef0fa5f4856f9b020

7 files changed, 92 insertions, 32 deletions

diff --git a/library/cpp/yt/error/convert_to_cpo.h b/library/cpp/yt/error/convert_to_cpo.h
index 55f608c3b60..dcfc8b0677d 100644
--- a/library/cpp/yt/error/convert_to_cpo.h
+++ b/library/cpp/yt/error/convert_to_cpo.h
@@ -2,8 +2,6 @@
 
 #include <library/cpp/yt/misc/tag_invoke_cpo.h>
 
-#include <util/generic/strbuf.h>
-
 namespace NYT {
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -34,7 +32,7 @@ inline constexpr NConvertToImpl::TFn<T> ConvertTo = {};
 ////////////////////////////////////////////////////////////////////////////////
 
 template <class TTo, class TFrom>
-concept CConvertToWorks = requires (const TFrom& from) {
+concept CConvertsTo = requires (const TFrom& from) {
     { NYT::ConvertTo<TTo>(from) } -> std::same_as<TTo>;
 };
 
diff --git a/library/cpp/yt/error/error_attribute.h b/library/cpp/yt/error/error_attribute.h
new file mode 100644
index 00000000000..dec4a4dd9b3
--- /dev/null
+++ b/library/cpp/yt/error/error_attribute.h
@@ -0,0 +1,57 @@
+#pragma once
+
+#include <library/cpp/yt/misc/tag_invoke_cpo.h>
+
+// TODO(arkady-e1ppa): Eliminate.
+#include <library/cpp/yt/yson_string/string.h>
+
+namespace NYT {
+
+////////////////////////////////////////////////////////////////////////////////
+
+namespace NToAttributeValueImpl {
+
+struct TFn
+    : public TTagInvokeCpoBase<TFn>
+{ };
+
+} // namespace NToAttributeValueImpl
+
+////////////////////////////////////////////////////////////////////////////////
+
+inline constexpr NToAttributeValueImpl::TFn ToAttributeValue = {};
+
+////////////////////////////////////////////////////////////////////////////////
+
+template <class T>
+concept CConvertibleToAttributeValue = CTagInvocableS<
+    TTagInvokeTag<ToAttributeValue>,
+    NYson::TYsonString(const T&)>;
+
+////////////////////////////////////////////////////////////////////////////////
+
+struct TErrorAttribute
+{
+    // NB(arkady-e1ppa): Switch to std::string is quite possible
+    // however it requires patching IAttributeDictionary or
+    // switching it to the std::string first for interop reasons.
+    // Do that later.
+    using TKey = TString;
+    // TODO(arkady-e1ppa): Use ConvertToYsonString(value, Format::Text)
+    // here for complex values. Write manual implementations as ToString
+    // for primitive types (e.g. integral types, guid, string, time).
+    using TValue = NYson::TYsonString;
+
+    template <CConvertibleToAttributeValue T>
+    TErrorAttribute(const TKey& key, const T& value)
+        : Key(key)
+        , Value(NYT::ToAttributeValue(value))
+    { }
+
+    TKey Key;
+    TValue Value;
+};
+
+////////////////////////////////////////////////////////////////////////////////
+
+} // namespace NYT
diff --git a/library/cpp/yt/error/error_attributes-inl.h b/library/cpp/yt/error/error_attributes-inl.h
index 8ffbf3e0a39..6574665865b 100644
--- a/library/cpp/yt/error/error_attributes-inl.h
+++ b/library/cpp/yt/error/error_attributes-inl.h
@@ -9,7 +9,7 @@ namespace NYT {
 ////////////////////////////////////////////////////////////////////////////////
 
 template <class T>
-    requires CConvertToWorks<T, TErrorAttributes::TValue>
+    requires CConvertsTo<T, TErrorAttributes::TValue>
 T TErrorAttributes::Get(TStringBuf key) const
 {
     auto yson = GetYson(key);
@@ -21,7 +21,7 @@ T TErrorAttributes::Get(TStringBuf key) const
 }
 
 template <class T>
-    requires CConvertToWorks<T, TErrorAttributes::TValue>
+    requires CConvertsTo<T, TErrorAttributes::TValue>
 typename TOptionalTraits<T>::TOptional TErrorAttributes::Find(TStringBuf key) const
 {
     auto yson = FindYson(key);
@@ -36,8 +36,8 @@ typename TOptionalTraits<T>::TOptional TErrorAttributes::Find(TStringBuf key) co
 }
 
 template <class T>
-    requires CConvertToWorks<T, TErrorAttributes::TValue>
-T TErrorAttributes::GetAndRemove(const TString& key)
+    requires CConvertsTo<T, TErrorAttributes::TValue>
+T TErrorAttributes::GetAndRemove(const TKey& key)
 {
     auto result = Get<T>(key);
     Remove(key);
@@ -45,15 +45,15 @@ T TErrorAttributes::GetAndRemove(const TString& key)
 }
 
 template <class T>
-    requires CConvertToWorks<T, TErrorAttributes::TValue>
+    requires CConvertsTo<T, TErrorAttributes::TValue>
 T TErrorAttributes::Get(TStringBuf key, const T& defaultValue) const
 {
     return Find<T>(key).value_or(defaultValue);
 }
 
 template <class T>
-    requires CConvertToWorks<T, TErrorAttributes::TValue>
-T TErrorAttributes::GetAndRemove(const TString& key, const T& defaultValue)
+    requires CConvertsTo<T, TErrorAttributes::TValue>
+T TErrorAttributes::GetAndRemove(const TKey& key, const T& defaultValue)
 {
     auto result = Find<T>(key);
     if (result) {
@@ -65,8 +65,8 @@ T TErrorAttributes::GetAndRemove(const TString& key, const T& defaultValue)
 }
 
 template <class T>
-    requires CConvertToWorks<T, TErrorAttributes::TValue>
-typename TOptionalTraits<T>::TOptional TErrorAttributes::FindAndRemove(const TString& key)
+    requires CConvertsTo<T, TErrorAttributes::TValue>
+typename TOptionalTraits<T>::TOptional TErrorAttributes::FindAndRemove(const TKey& key)
 {
     auto result = Find<T>(key);
     if (result) {
diff --git a/library/cpp/yt/error/error_attributes.cpp b/library/cpp/yt/error/error_attributes.cpp
index 2c1b5423146..09aa48eebb9 100644
--- a/library/cpp/yt/error/error_attributes.cpp
+++ b/library/cpp/yt/error/error_attributes.cpp
@@ -15,7 +15,7 @@ void TErrorAttributes::Clear()
     }
 }
 
-NYson::TYsonString TErrorAttributes::GetYsonAndRemove(const TString& key)
+TErrorAttributes::TValue TErrorAttributes::GetYsonAndRemove(const TKey& key)
 {
     auto result = GetYson(key);
     Remove(key);
diff --git a/library/cpp/yt/error/error_attributes.h b/library/cpp/yt/error/error_attributes.h
index 7c2f4a54078..80dd80de484 100644
--- a/library/cpp/yt/error/error_attributes.h
+++ b/library/cpp/yt/error/error_attributes.h
@@ -1,6 +1,7 @@
 #pragma once
 
 #include "convert_to_cpo.h"
+#include "error_attribute.h"
 #include "mergeable_dictionary.h"
 
 #include <library/cpp/yt/misc/optional.h>
@@ -20,34 +21,34 @@ namespace NYT {
 class TErrorAttributes
 {
 public:
-    using TKey = TString;
-    using TValue = NYson::TYsonString;
+    using TKey = TErrorAttribute::TKey;
+    using TValue = TErrorAttribute::TValue;
     using TKeyValuePair = std::pair<TKey, TValue>;
 
     //! Returns the list of all keys in the dictionary.
-    std::vector<TString> ListKeys() const;
+    std::vector<TKey> ListKeys() const;
 
     //! Returns the list of all key-value pairs in the dictionary.
     std::vector<TKeyValuePair> ListPairs() const;
 
     //! Returns the value of the attribute (null indicates that the attribute is not found).
-    NYson::TYsonString FindYson(TStringBuf key) const;
+    TValue FindYson(TStringBuf key) const;
 
     //! Sets the value of the attribute.
-    void SetYson(const TString& key, const NYson::TYsonString& value);
+    void SetYson(const TKey& key, const TValue& value);
 
     //! Removes the attribute.
     //! Returns |true| if the attribute was removed or |false| if there is no attribute with this key.
-    bool Remove(const TString& key);
+    bool Remove(const TKey& key);
 
     //! Removes all attributes.
     void Clear();
 
     //! Returns the value of the attribute (throws an exception if the attribute is not found).
-    NYson::TYsonString GetYson(TStringBuf key) const;
+    TValue GetYson(TStringBuf key) const;
 
     //! Same as #GetYson but removes the value.
-    NYson::TYsonString GetYsonAndRemove(const TString& key);
+    TValue GetYsonAndRemove(const TKey& key);
 
     //! Returns |true| iff the given key is present.
     bool Contains(TStringBuf key) const;
@@ -58,35 +59,35 @@ public:
     //! Finds the attribute and deserializes its value.
     //! Throws if no such value is found.
     template <class T>
-        requires CConvertToWorks<T, TValue>
+        requires CConvertsTo<T, TValue>
     T Get(TStringBuf key) const;
 
     //! Same as #Get but removes the value.
     template <class T>
-        requires CConvertToWorks<T, TValue>
-    T GetAndRemove(const TString& key);
+        requires CConvertsTo<T, TValue>
+    T GetAndRemove(const TKey& key);
 
     //! Finds the attribute and deserializes its value.
     //! Uses default value if no such attribute is found.
     template <class T>
-        requires CConvertToWorks<T, TValue>
+        requires CConvertsTo<T, TValue>
     T Get(TStringBuf key, const T& defaultValue) const;
 
     //! Same as #Get but removes the value if it exists.
     template <class T>
-        requires CConvertToWorks<T, TValue>
-    T GetAndRemove(const TString& key, const T& defaultValue);
+        requires CConvertsTo<T, TValue>
+    T GetAndRemove(const TKey& key, const T& defaultValue);
 
     //! Finds the attribute and deserializes its value.
     //! Returns null if no such attribute is found.
     template <class T>
-        requires CConvertToWorks<T, TValue>
+        requires CConvertsTo<T, TValue>
     typename TOptionalTraits<T>::TOptional Find(TStringBuf key) const;
 
     //! Same as #Find but removes the value if it exists.
     template <class T>
-        requires CConvertToWorks<T, TValue>
-    typename TOptionalTraits<T>::TOptional FindAndRemove(const TString& key);
+        requires CConvertsTo<T, TValue>
+    typename TOptionalTraits<T>::TOptional FindAndRemove(const TKey& key);
 
     template <CMergeableDictionary TDictionary>
     void MergeFrom(const TDictionary& dict);
diff --git a/library/cpp/yt/error/mergeable_dictionary.h b/library/cpp/yt/error/mergeable_dictionary.h
index 90597059e40..361694d8416 100644
--- a/library/cpp/yt/error/mergeable_dictionary.h
+++ b/library/cpp/yt/error/mergeable_dictionary.h
@@ -1,6 +1,7 @@
 #pragma once
 
 #include "public.h"
+#include "error_attribute.h"
 
 #include <ranges>
 
@@ -23,6 +24,7 @@ namespace NDetail {
 template <class T>
 struct TMergeableDictionaryImpl
 {
+    // TL;DR: MakeIterableView returns something like std::span<std::pair<TKey, TValue>>.
     using TView = std::invoke_result_t<decltype(&TMergeDictionariesTraits<T>::MakeIterableView), const T&>;
     using TIterator = std::ranges::iterator_t<TView>;
     using TValue = typename std::iterator_traits<TIterator>::value_type;
@@ -33,10 +35,10 @@ struct TMergeableDictionaryImpl
 
     static constexpr bool CorrectTupleElements = requires {
         typename std::tuple_element<0, TValue>::type;
-        std::same_as<typename std::tuple_element<0, TValue>::type, TString>;
+        std::same_as<typename std::tuple_element<0, TValue>::type, TErrorAttribute::TKey>;
 
         typename std::tuple_element<1, TValue>::type;
-        std::same_as<typename std::tuple_element<1, TValue>::type, NYson::TYsonString>;
+        std::same_as<typename std::tuple_element<1, TValue>::type, TErrorAttribute::TValue>;
     };
 };
 
diff --git a/library/cpp/yt/error/public.h b/library/cpp/yt/error/public.h
index 63b95497c7b..04201128aa3 100644
--- a/library/cpp/yt/error/public.h
+++ b/library/cpp/yt/error/public.h
@@ -9,6 +9,8 @@ namespace NYT {
 template <class T>
 class TErrorOr;
 
+
+struct TErrorAttribute;
 class TErrorAttributes;
 struct TOriginAttributes;