YT: Allow heterogeneous lookup for TCompactFlatMap

b7397bff929c40b73c27256bbf9be5a5594ebafa

4 files changed, 139 insertions, 122 deletions

diff --git a/library/cpp/yt/small_containers/compact_flat_map-inl.h b/library/cpp/yt/small_containers/compact_flat_map-inl.h
index 459d72fa2c1..e781569d9da 100644
--- a/library/cpp/yt/small_containers/compact_flat_map-inl.h
+++ b/library/cpp/yt/small_containers/compact_flat_map-inl.h
@@ -8,137 +8,140 @@ namespace NYT {
 
 ///////////////////////////////////////////////////////////////////////////////
 
-template <class K, class V, size_t N>
+template <class TKey, class TValue, size_t N, class TKeyCompare>
 template <class TInputIterator>
-TCompactFlatMap<K, V, N>::TCompactFlatMap(TInputIterator begin, TInputIterator end)
+TCompactFlatMap<TKey, TValue, N, TKeyCompare>::TCompactFlatMap(TInputIterator begin, TInputIterator end)
 {
     insert(begin, end);
 }
 
-template <class K, class V, size_t N>
-TCompactFlatMap<K, V, N>::TCompactFlatMap(std::initializer_list<value_type> values)
-    : TCompactFlatMap<K, V, N>(values.begin(), values.end())
+template <class TKey, class TValue, size_t N, class TKeyCompare>
+TCompactFlatMap<TKey, TValue, N, TKeyCompare>::TCompactFlatMap(std::initializer_list<value_type> values)
+    : TCompactFlatMap<TKey, TValue, N, TKeyCompare>(values.begin(), values.end())
 { }
 
-template <class K, class V, size_t N>
-bool TCompactFlatMap<K, V, N>::operator==(const TCompactFlatMap& rhs) const
+template <class TKey, class TValue, size_t N, class TKeyCompare>
+bool TCompactFlatMap<TKey, TValue, N, TKeyCompare>::operator==(const TCompactFlatMap& rhs) const
 {
     return Storage_ == rhs.Storage_;
 }
 
-template <class K, class V, size_t N>
-bool TCompactFlatMap<K, V, N>::operator!=(const TCompactFlatMap& rhs) const
+template <class TKey, class TValue, size_t N, class TKeyCompare>
+bool TCompactFlatMap<TKey, TValue, N, TKeyCompare>::operator!=(const TCompactFlatMap& rhs) const
 {
     return !(*this == rhs);
 }
 
-template <class K, class V, size_t N>
-typename TCompactFlatMap<K, V, N>::iterator TCompactFlatMap<K, V, N>::begin()
+template <class TKey, class TValue, size_t N, class TKeyCompare>
+typename TCompactFlatMap<TKey, TValue, N, TKeyCompare>::iterator TCompactFlatMap<TKey, TValue, N, TKeyCompare>::begin()
 {
     return Storage_.begin();
 }
 
-template <class K, class V, size_t N>
-typename TCompactFlatMap<K, V, N>::const_iterator TCompactFlatMap<K, V, N>::begin() const
+template <class TKey, class TValue, size_t N, class TKeyCompare>
+typename TCompactFlatMap<TKey, TValue, N, TKeyCompare>::const_iterator TCompactFlatMap<TKey, TValue, N, TKeyCompare>::begin() const
 {
     return Storage_.begin();
 }
 
-template <class K, class V, size_t N>
-typename TCompactFlatMap<K, V, N>::const_iterator TCompactFlatMap<K, V, N>::cbegin() const
+template <class TKey, class TValue, size_t N, class TKeyCompare>
+typename TCompactFlatMap<TKey, TValue, N, TKeyCompare>::const_iterator TCompactFlatMap<TKey, TValue, N, TKeyCompare>::cbegin() const
 {
     return Storage_.begin();
 }
 
-template <class K, class V, size_t N>
-typename TCompactFlatMap<K, V, N>::iterator TCompactFlatMap<K, V, N>::end()
+template <class TKey, class TValue, size_t N, class TKeyCompare>
+typename TCompactFlatMap<TKey, TValue, N, TKeyCompare>::iterator TCompactFlatMap<TKey, TValue, N, TKeyCompare>::end()
 {
     return Storage_.end();
 }
 
-template <class K, class V, size_t N>
-typename TCompactFlatMap<K, V, N>::const_iterator TCompactFlatMap<K, V, N>::end() const
+template <class TKey, class TValue, size_t N, class TKeyCompare>
+typename TCompactFlatMap<TKey, TValue, N, TKeyCompare>::const_iterator TCompactFlatMap<TKey, TValue, N, TKeyCompare>::end() const
 {
     return Storage_.end();
 }
 
-template <class K, class V, size_t N>
-typename TCompactFlatMap<K, V, N>::const_iterator TCompactFlatMap<K, V, N>::cend() const
+template <class TKey, class TValue, size_t N, class TKeyCompare>
+typename TCompactFlatMap<TKey, TValue, N, TKeyCompare>::const_iterator TCompactFlatMap<TKey, TValue, N, TKeyCompare>::cend() const
 {
     return Storage_.end();
 }
 
-template <class K, class V, size_t N>
-void TCompactFlatMap<K, V, N>::reserve(size_type n)
+template <class TKey, class TValue, size_t N, class TKeyCompare>
+void TCompactFlatMap<TKey, TValue, N, TKeyCompare>::reserve(size_type n)
 {
     Storage_.reserve(n);
 }
 
-template <class K, class V, size_t N>
-typename TCompactFlatMap<K, V, N>::size_type TCompactFlatMap<K, V, N>::size() const
+template <class TKey, class TValue, size_t N, class TKeyCompare>
+typename TCompactFlatMap<TKey, TValue, N, TKeyCompare>::size_type TCompactFlatMap<TKey, TValue, N, TKeyCompare>::size() const
 {
     return Storage_.size();
 }
 
-template <class K, class V, size_t N>
-int TCompactFlatMap<K, V, N>::ssize() const
+template <class TKey, class TValue, size_t N, class TKeyCompare>
+int TCompactFlatMap<TKey, TValue, N, TKeyCompare>::ssize() const
 {
     return static_cast<int>(Storage_.size());
 }
 
-template <class K, class V, size_t N>
-bool TCompactFlatMap<K, V, N>::empty() const
+template <class TKey, class TValue, size_t N, class TKeyCompare>
+bool TCompactFlatMap<TKey, TValue, N, TKeyCompare>::empty() const
 {
     return Storage_.empty();
 }
 
-template <class K, class V, size_t N>
-void TCompactFlatMap<K, V, N>::clear()
+template <class TKey, class TValue, size_t N, class TKeyCompare>
+void TCompactFlatMap<TKey, TValue, N, TKeyCompare>::clear()
 {
     Storage_.clear();
 }
 
-template <class K, class V, size_t N>
-void TCompactFlatMap<K, V, N>::shrink_to_small()
+template <class TKey, class TValue, size_t N, class TKeyCompare>
+void TCompactFlatMap<TKey, TValue, N, TKeyCompare>::shrink_to_small()
 {
     Storage_.shrink_to_small();
 }
 
-template <class K, class V, size_t N>
-typename TCompactFlatMap<K, V, N>::iterator TCompactFlatMap<K, V, N>::find(const K& k)
+template <class TKey, class TValue, size_t N, class TKeyCompare>
+template <NDetail::CComparisonAllowed<TKey, TKeyCompare> TOtherKey>
+typename TCompactFlatMap<TKey, TValue, N, TKeyCompare>::iterator TCompactFlatMap<TKey, TValue, N, TKeyCompare>::find(const TOtherKey& k)
 {
     auto [rangeBegin, rangeEnd] = equal_range(k);
     return rangeBegin == rangeEnd ? end() : rangeBegin;
 }
 
-template <class K, class V, size_t N>
-typename TCompactFlatMap<K, V, N>::const_iterator TCompactFlatMap<K, V, N>::find(const K& k) const
+template <class TKey, class TValue, size_t N, class TKeyCompare>
+template <NDetail::CComparisonAllowed<TKey, TKeyCompare> TOtherKey>
+typename TCompactFlatMap<TKey, TValue, N, TKeyCompare>::const_iterator TCompactFlatMap<TKey, TValue, N, TKeyCompare>::find(const TOtherKey& k) const
 {
     auto [rangeBegin, rangeEnd] = equal_range(k);
     return rangeBegin == rangeEnd ? end() : rangeBegin;
 }
 
-template <class K, class V, size_t N>
-bool TCompactFlatMap<K, V, N>::contains(const K& k) const
+template <class TKey, class TValue, size_t N, class TKeyCompare>
+template <NDetail::CComparisonAllowed<TKey, TKeyCompare> TOtherKey>
+bool TCompactFlatMap<TKey, TValue, N, TKeyCompare>::contains(const TOtherKey& k) const
 {
     return find(k) != end();
 }
 
-template <class K, class V, size_t N>
-auto TCompactFlatMap<K, V, N>::insert(const value_type& value) -> std::pair<iterator, bool>
+template <class TKey, class TValue, size_t N, class TKeyCompare>
+auto TCompactFlatMap<TKey, TValue, N, TKeyCompare>::insert(const value_type& value) -> std::pair<iterator, bool>
 {
     return do_insert(value);
 }
 
-template <class K, class V, size_t N>
-auto TCompactFlatMap<K, V, N>::insert(value_type&& value) -> std::pair<iterator, bool>
+template <class TKey, class TValue, size_t N, class TKeyCompare>
+auto TCompactFlatMap<TKey, TValue, N, TKeyCompare>::insert(value_type&& value) -> std::pair<iterator, bool>
 {
     return do_insert(std::move(value));
 }
 
-template <class K, class V, size_t N>
+template <class TKey, class TValue, size_t N, class TKeyCompare>
 template <class TArg>
-auto TCompactFlatMap<K, V, N>::do_insert(TArg&& value) -> std::pair<iterator, bool>
+auto TCompactFlatMap<TKey, TValue, N, TKeyCompare>::do_insert(TArg&& value) -> std::pair<iterator, bool>
 {
     auto [rangeBegin, rangeEnd] = equal_range(value.first);
     if (rangeBegin != rangeEnd) {
@@ -149,38 +152,38 @@ auto TCompactFlatMap<K, V, N>::do_insert(TArg&& value) -> std::pair<iterator, bo
     }
 }
 
-template <class K, class V, size_t N>
+template <class TKey, class TValue, size_t N, class TKeyCompare>
 template <class TInputIterator>
-void TCompactFlatMap<K, V, N>::insert(TInputIterator begin, TInputIterator end)
+void TCompactFlatMap<TKey, TValue, N, TKeyCompare>::insert(TInputIterator begin, TInputIterator end)
 {
     for (auto it = begin; it != end; ++it) {
         insert(*it);
     }
 }
 
-template <class K, class V, size_t N>
+template <class TKey, class TValue, size_t N, class TKeyCompare>
 template <class... TArgs>
-auto TCompactFlatMap<K, V, N>::emplace(TArgs&&... args) -> std::pair<iterator, bool>
+auto TCompactFlatMap<TKey, TValue, N, TKeyCompare>::emplace(TArgs&&... args) -> std::pair<iterator, bool>
 {
     return insert(value_type(std::forward<TArgs>(args)...));
 }
 
-template <class K, class V, size_t N>
-V& TCompactFlatMap<K, V, N>::operator[](const K& k)
+template <class TKey, class TValue, size_t N, class TKeyCompare>
+TValue& TCompactFlatMap<TKey, TValue, N, TKeyCompare>::operator[](const TKey& k)
 {
-    auto [it, inserted] = insert({k, V()});
+    auto [it, inserted] = insert({k, TValue()});
     return it->second;
 }
 
-template <class K, class V, size_t N>
-void TCompactFlatMap<K, V, N>::erase(const K& k)
+template <class TKey, class TValue, size_t N, class TKeyCompare>
+void TCompactFlatMap<TKey, TValue, N, TKeyCompare>::erase(const TKey& k)
 {
     auto [rangeBegin, rangeEnd] = equal_range(k);
     erase(rangeBegin, rangeEnd);
 }
 
-template <class K, class V, size_t N>
-void TCompactFlatMap<K, V, N>::erase(iterator pos)
+template <class TKey, class TValue, size_t N, class TKeyCompare>
+void TCompactFlatMap<TKey, TValue, N, TKeyCompare>::erase(iterator pos)
 {
     Storage_.erase(pos);
 
@@ -188,8 +191,8 @@ void TCompactFlatMap<K, V, N>::erase(iterator pos)
     Storage_.shrink_to_small();
 }
 
-template <class K, class V, size_t N>
-void TCompactFlatMap<K, V, N>::erase(iterator b, iterator e)
+template <class TKey, class TValue, size_t N, class TKeyCompare>
+void TCompactFlatMap<TKey, TValue, N, TKeyCompare>::erase(iterator b, iterator e)
 {
     Storage_.erase(b, e);
 
@@ -197,46 +200,52 @@ void TCompactFlatMap<K, V, N>::erase(iterator b, iterator e)
     Storage_.shrink_to_small();
 }
 
-template <class K, class V, size_t N>
-std::pair<typename TCompactFlatMap<K, V, N>::iterator, typename TCompactFlatMap<K, V, N>::iterator>
-TCompactFlatMap<K, V, N>::equal_range(const K& k)
+template <class TKey, class TValue, size_t N, class TKeyCompare>
+template <NDetail::CComparisonAllowed<TKey, TKeyCompare> TOtherKey>
+std::pair<typename TCompactFlatMap<TKey, TValue, N, TKeyCompare>::iterator, typename TCompactFlatMap<TKey, TValue, N, TKeyCompare>::iterator>
+TCompactFlatMap<TKey, TValue, N, TKeyCompare>::equal_range(const TOtherKey& k)
 {
-    auto result = std::equal_range(Storage_.begin(), Storage_.end(), k, TKeyComparer());
-    YT_ASSERT(std::distance(result.first, result.second) <= 1);
+    auto result = std::ranges::equal_range(Storage_, k, {}, &value_type::first);
+    YT_ASSERT(result.size() <= 1);
     return result;
 }
 
-template <class K, class V, size_t N>
-std::pair<typename TCompactFlatMap<K, V, N>::const_iterator, typename TCompactFlatMap<K, V, N>::const_iterator>
-TCompactFlatMap<K, V, N>::equal_range(const K& k) const
+template <class TKey, class TValue, size_t N, class TKeyCompare>
+template <NDetail::CComparisonAllowed<TKey, TKeyCompare> TOtherKey>
+std::pair<typename TCompactFlatMap<TKey, TValue, N, TKeyCompare>::const_iterator, typename TCompactFlatMap<TKey, TValue, N, TKeyCompare>::const_iterator>
+TCompactFlatMap<TKey, TValue, N, TKeyCompare>::equal_range(const TOtherKey& k) const
 {
-    auto result = std::equal_range(Storage_.begin(), Storage_.end(), k, TKeyComparer());
-    YT_ASSERT(std::distance(result.first, result.second) <= 1);
+    auto result = std::ranges::equal_range(Storage_, k, {}, &value_type::first);
+    YT_ASSERT(result.size() <= 1);
     return result;
 }
 
-template <class K, class V, size_t N>
-typename TCompactFlatMap<K, V, N>::const_iterator TCompactFlatMap<K, V, N>::lower_bound(const K& k) const
+template <class TKey, class TValue, size_t N, class TKeyCompare>
+template <NDetail::CComparisonAllowed<TKey, TKeyCompare> TOtherKey>
+typename TCompactFlatMap<TKey, TValue, N, TKeyCompare>::const_iterator TCompactFlatMap<TKey, TValue, N, TKeyCompare>::lower_bound(const TOtherKey& k) const
 {
-    return std::lower_bound(Storage_.begin(), Storage_.end(), k, TKeyComparer());
+    return std::ranges::lower_bound(Storage_, k, {}, &value_type::first);
 }
 
-template <class K, class V, size_t N>
-typename TCompactFlatMap<K, V, N>::iterator TCompactFlatMap<K, V, N>::lower_bound(const K& k)
+template <class TKey, class TValue, size_t N, class TKeyCompare>
+template <NDetail::CComparisonAllowed<TKey, TKeyCompare> TOtherKey>
+typename TCompactFlatMap<TKey, TValue, N, TKeyCompare>::iterator TCompactFlatMap<TKey, TValue, N, TKeyCompare>::lower_bound(const TOtherKey& k)
 {
-    return std::lower_bound(Storage_.begin(), Storage_.end(), k, TKeyComparer());
+    return std::ranges::lower_bound(Storage_, k, {}, &value_type::first);
 }
 
-template <class K, class V, size_t N>
-typename TCompactFlatMap<K, V, N>::const_iterator TCompactFlatMap<K, V, N>::upper_bound(const K& k) const
+template <class TKey, class TValue, size_t N, class TKeyCompare>
+template <NDetail::CComparisonAllowed<TKey, TKeyCompare> TOtherKey>
+typename TCompactFlatMap<TKey, TValue, N, TKeyCompare>::const_iterator TCompactFlatMap<TKey, TValue, N, TKeyCompare>::upper_bound(const TOtherKey& k) const
 {
-    return std::upper_bound(Storage_.begin(), Storage_.end(), k, TKeyComparer());
+    return std::ranges::upper_bound(Storage_, k, {}, &value_type::first);
 }
 
-template <class K, class V, size_t N>
-typename TCompactFlatMap<K, V, N>::iterator TCompactFlatMap<K, V, N>::upper_bound(const K& k)
+template <class TKey, class TValue, size_t N, class TKeyCompare>
+template <NDetail::CComparisonAllowed<TKey, TKeyCompare> TOtherKey>
+typename TCompactFlatMap<TKey, TValue, N, TKeyCompare>::iterator TCompactFlatMap<TKey, TValue, N, TKeyCompare>::upper_bound(const TOtherKey& k)
 {
-    return std::upper_bound(Storage_.begin(), Storage_.end(), k, TKeyComparer());
+    return std::ranges::upper_bound(Storage_, k, {}, &value_type::first);
 }
 
 ////////////////////////////////////////////////////////////////////////////////
diff --git a/library/cpp/yt/small_containers/compact_flat_map.h b/library/cpp/yt/small_containers/compact_flat_map.h
index b598a34731c..120c2141b92 100644
--- a/library/cpp/yt/small_containers/compact_flat_map.h
+++ b/library/cpp/yt/small_containers/compact_flat_map.h
@@ -4,9 +4,21 @@
 
 namespace NYT {
 
+namespace NDetail {
+
+template <typename T>
+concept CHasIsTransparentFlag = requires {
+    typename T::is_transparent;
+};
+
+template <typename T, typename U, typename TCompare>
+concept CComparisonAllowed = std::same_as<T, U> || CHasIsTransparentFlag<TCompare>;
+
+} // namespace NDetail
+
 ///////////////////////////////////////////////////////////////////////////////
 
-//! A flat map implementation over TCompactVector that tries to keep data inline.
+//! A flat map implementation over TCompactTValueector that tries to keep data inline.
 /*!
  *  Similarly to SmallSet, this is implemented via binary search over a sorted
  *  vector. Unlike SmallSet, however, this one never falls back to std::map (or
@@ -21,32 +33,20 @@ namespace NYT {
  *  Because of the latter, one should be very careful with iterators: virtually
  *  any call to insert or erase may potentially invalidate all iterators.
  */
-template <class K, class V, size_t N>
+template <class TKey, class TValue, size_t N, class TKeyCompare = std::ranges::less>
 class TCompactFlatMap
 {
 public:
-    // NB: can't make this pair<const K, V> as TCompactVector requires its type
+    // NB: can't make this pair<const TKey, TValue> as TCompactTValueector requires its type
     // parameter to be copy-assignable.
-    using value_type = std::pair<K, V>;
-    using key_type = K;
-    using mapped_type = V;
+    using value_type = std::pair<TKey, TValue>;
+    using key_type = TKey;
+    using mapped_type = TValue;
+    using key_compare = TKeyCompare;
 
 private:
     using TStorage = TCompactVector<value_type, N>;
 
-    struct TKeyComparer
-    {
-        bool operator()(const K& lhs, const value_type& rhs)
-        {
-            return lhs < rhs.first;
-        }
-
-        bool operator()(const value_type& lhs, const K& rhs)
-        {
-            return lhs.first < rhs;
-        }
-    };
-
 public:
     using iterator = typename TStorage::iterator;
     using const_iterator = typename TStorage::const_iterator;
@@ -80,17 +80,26 @@ public:
 
     void shrink_to_small();
 
-    iterator find(const K& k);
-    const_iterator find(const K& k) const;
-
-    iterator lower_bound(const K& k);
-    const_iterator lower_bound(const K& k) const;
-    iterator upper_bound(const K& k);
-    const_iterator upper_bound(const K& k) const;
-    std::pair<iterator, iterator> equal_range(const K& k);
-    std::pair<const_iterator, const_iterator> equal_range(const K& k) const;
-
-    bool contains(const K& k) const;
+    template <NDetail::CComparisonAllowed<TKey, TKeyCompare> TOtherKey>
+    iterator find(const TOtherKey& k);
+    template <NDetail::CComparisonAllowed<TKey, TKeyCompare> TOtherKey>
+    const_iterator find(const TOtherKey& k) const;
+
+    template <NDetail::CComparisonAllowed<TKey, TKeyCompare> TOtherKey>
+    iterator lower_bound(const TOtherKey& k);
+    template <NDetail::CComparisonAllowed<TKey, TKeyCompare> TOtherKey>
+    const_iterator lower_bound(const TOtherKey& k) const;
+    template <NDetail::CComparisonAllowed<TKey, TKeyCompare> TOtherKey>
+    iterator upper_bound(const TOtherKey& k);
+    template <NDetail::CComparisonAllowed<TKey, TKeyCompare> TOtherKey>
+    const_iterator upper_bound(const TOtherKey& k) const;
+    template <NDetail::CComparisonAllowed<TKey, TKeyCompare> TOtherKey>
+    std::pair<iterator, iterator> equal_range(const TOtherKey& k);
+    template <NDetail::CComparisonAllowed<TKey, TKeyCompare> TOtherKey>
+    std::pair<const_iterator, const_iterator> equal_range(const TOtherKey& k) const;
+
+    template <NDetail::CComparisonAllowed<TKey, TKeyCompare> TOtherKey>
+    bool contains(const TOtherKey& k) const;
 
     std::pair<iterator, bool> insert(const value_type& value);
     std::pair<iterator, bool> insert(value_type&& value);
@@ -101,9 +110,9 @@ public:
     template <class... TArgs>
     std::pair<iterator, bool> emplace(TArgs&&... args);
 
-    V& operator[](const K& k);
+    TValue& operator[](const TKey& k);
 
-    void erase(const K& k);
+    void erase(const TKey& k);
     void erase(iterator pos);
     void erase(iterator b, iterator e);
 
diff --git a/library/cpp/yt/small_containers/compact_set-inl.h b/library/cpp/yt/small_containers/compact_set-inl.h
index e93d11f126f..20736f50833 100644
--- a/library/cpp/yt/small_containers/compact_set-inl.h
+++ b/library/cpp/yt/small_containers/compact_set-inl.h
@@ -216,19 +216,19 @@ bool TCompactSet<T, N, C, A>::empty() const
 template <typename T, size_t N,  typename C, typename A>
 typename TCompactSet<T, N, C, A>::size_type TCompactSet<T, N, C, A>::size() const
 {
-    return is_small() ? Vector_.size() : Set_.size();
+    return IsSmall() ? Vector_.size() : Set_.size();
 }
 
 template <typename T, size_t N,  typename C, typename A>
 const T& TCompactSet<T, N, C, A>::front() const
 {
-    return is_small() ? Vector_.front() : *Set_.begin();
+    return IsSmall() ? Vector_.front() : *Set_.begin();
 }
 
 template <typename T, size_t N,  typename C, typename A>
 typename TCompactSet<T, N, C, A>::size_type TCompactSet<T, N, C, A>::count(const T& v) const
 {
-    if (is_small()) {
+    if (IsSmall()) {
         return std::binary_search(Vector_.begin(), Vector_.end(), v, C()) ? 1 : 0;
     } else {
         return Set_.count(v);
@@ -244,7 +244,7 @@ bool TCompactSet<T, N, C, A>::contains(const T& v) const
 template <typename T, size_t N,  typename C, typename A>
 std::pair<typename TCompactSet<T, N, C, A>::const_iterator, bool> TCompactSet<T, N, C, A>::insert(const T& v)
 {
-    if (!is_small()) {
+    if (!IsSmall()) {
         auto [it, inserted] = Set_.insert(v);
         return {const_iterator(std::move(it)), inserted};
     }
@@ -279,7 +279,7 @@ void TCompactSet<T, N, C, A>::insert(TIter i, TIter e)
 template <typename T, size_t N,  typename C, typename A>
 bool TCompactSet<T, N, C, A>::erase(const T& v)
 {
-    if (!is_small()) {
+    if (!IsSmall()) {
         return Set_.erase(v);
     }
 
@@ -302,7 +302,7 @@ void TCompactSet<T, N, C, A>::clear()
 template <typename T, size_t N,  typename C, typename A>
 typename TCompactSet<T, N, C, A>::const_iterator TCompactSet<T, N, C, A>::begin() const
 {
-    return is_small() ? const_iterator(Vector_.begin()) : const_iterator(Set_.begin());
+    return IsSmall() ? const_iterator(Vector_.begin()) : const_iterator(Set_.begin());
 }
 
 template <typename T, size_t N,  typename C, typename A>
@@ -314,7 +314,7 @@ typename TCompactSet<T, N, C, A>::const_iterator TCompactSet<T, N, C, A>::cbegin
 template <typename T, size_t N,  typename C, typename A>
 typename TCompactSet<T, N, C, A>::const_iterator TCompactSet<T, N, C, A>::end() const
 {
-    return is_small() ? const_iterator(Vector_.end()) : const_iterator(Set_.end());
+    return IsSmall() ? const_iterator(Vector_.end()) : const_iterator(Set_.end());
 }
 
 template <typename T, size_t N,  typename C, typename A>
@@ -324,7 +324,7 @@ typename TCompactSet<T, N, C, A>::const_iterator TCompactSet<T, N, C, A>::cend()
 }
 
 template <typename T, size_t N,  typename C, typename A>
-bool TCompactSet<T, N, C, A>::is_small() const
+bool TCompactSet<T, N, C, A>::IsSmall() const
 {
     return Set_.empty();
 }
diff --git a/library/cpp/yt/small_containers/compact_set.h b/library/cpp/yt/small_containers/compact_set.h
index ca5e3c6efd7..354fad195cd 100644
--- a/library/cpp/yt/small_containers/compact_set.h
+++ b/library/cpp/yt/small_containers/compact_set.h
@@ -80,7 +80,7 @@ private:
     using TSetConstIterator = typename std::set<T, C, A>::const_iterator;
     using TVectorConstIterator = typename TCompactVector<T, N>::const_iterator;
 
-    bool is_small() const;
+    bool IsSmall() const;
 };
 
 ///////////////////////////////////////////////////////////////////////////////
@@ -90,4 +90,3 @@ private:
 #define COMPACT_SET_INL_H_
 #include "compact_set-inl.h"
 #undef COMPACT_SET_INL_H_
-