Mark clear and reset methods as reinitializing the object.

This means, that moved-from object can be safely used after the call of such method.
This attribute is used by clang-tidy which checks that moved-from objects are not used 
unless a reinitialization method is called first.

12 files changed, 61 insertions, 41 deletions

diff --git a/contrib/libs/cxxsupp/libcxx/include/__config b/contrib/libs/cxxsupp/libcxx/include/__config
index 1984c01ed73..3f383a82d01 100644
--- a/contrib/libs/cxxsupp/libcxx/include/__config
+++ b/contrib/libs/cxxsupp/libcxx/include/__config
@@ -1325,6 +1325,12 @@ extern "C" _LIBCPP_FUNC_VIS void __sanitizer_annotate_contiguous_container(
 #  define _LIBCPP_FALLTHROUGH() ((void)0)
 #endif
 
+#if defined(_LIBCPP_COMPILER_CLANG_BASED)
+# define _LIBCPP_REINITIALIZES_OBJECT [[clang::reinitializes]]
+#else
+# define _LIBCPP_REINITIALIZES_OBJECT
+#endif
+
 #if __has_attribute(__nodebug__) && !defined(__CUDACC__)
 #define _LIBCPP_NODEBUG __attribute__((__nodebug__))
 #else
diff --git a/contrib/libs/cxxsupp/libcxx/include/deque b/contrib/libs/cxxsupp/libcxx/include/deque
index 50a8b381534..a4ab230742f 100644
--- a/contrib/libs/cxxsupp/libcxx/include/deque
+++ b/contrib/libs/cxxsupp/libcxx/include/deque
@@ -1467,7 +1467,7 @@ public:
         _NOEXCEPT_(!__alloc_traits::propagate_on_container_swap::value ||
                    __is_nothrow_swappable<allocator_type>::value);
 #endif
-    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_REINITIALIZES_OBJECT _LIBCPP_INLINE_VISIBILITY
     void clear() _NOEXCEPT;
 
     _LIBCPP_INLINE_VISIBILITY
@@ -2948,6 +2948,7 @@ deque<_Tp, _Allocator>::swap(deque& __c)
 }
 
 template <class _Tp, class _Allocator>
+_LIBCPP_REINITIALIZES_OBJECT
 inline
 void
 deque<_Tp, _Allocator>::clear() _NOEXCEPT
diff --git a/contrib/libs/cxxsupp/libcxx/include/map b/contrib/libs/cxxsupp/libcxx/include/map
index aaf4b616209..d6a5ad1fa4b 100644
--- a/contrib/libs/cxxsupp/libcxx/include/map
+++ b/contrib/libs/cxxsupp/libcxx/include/map
@@ -1370,7 +1370,7 @@ public:
     _LIBCPP_INLINE_VISIBILITY
     iterator  erase(const_iterator __f, const_iterator __l)
         {return __tree_.erase(__f.__i_, __l.__i_);}
-    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_REINITIALIZES_OBJECT _LIBCPP_INLINE_VISIBILITY
     void clear() _NOEXCEPT {__tree_.clear();}
 
 #if _LIBCPP_STD_VER > 14
@@ -2112,7 +2112,7 @@ public:
     }
 #endif
 
-    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_REINITIALIZES_OBJECT _LIBCPP_INLINE_VISIBILITY
     void clear() _NOEXCEPT {__tree_.clear();}
 
     _LIBCPP_INLINE_VISIBILITY
diff --git a/contrib/libs/cxxsupp/libcxx/include/set b/contrib/libs/cxxsupp/libcxx/include/set
index 04b6f52c084..99a061a0387 100644
--- a/contrib/libs/cxxsupp/libcxx/include/set
+++ b/contrib/libs/cxxsupp/libcxx/include/set
@@ -745,7 +745,7 @@ public:
     _LIBCPP_INLINE_VISIBILITY
     iterator  erase(const_iterator __f, const_iterator __l)
         {return __tree_.erase(__f, __l);}
-    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_REINITIALIZES_OBJECT _LIBCPP_INLINE_VISIBILITY
     void clear() _NOEXCEPT {__tree_.clear();}
 
 #if _LIBCPP_STD_VER > 14
@@ -1276,7 +1276,7 @@ public:
     _LIBCPP_INLINE_VISIBILITY
     iterator  erase(const_iterator __f, const_iterator __l)
         {return __tree_.erase(__f, __l);}
-    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_REINITIALIZES_OBJECT _LIBCPP_INLINE_VISIBILITY
     void clear() _NOEXCEPT {__tree_.clear();}
 
 #if _LIBCPP_STD_VER > 14
diff --git a/contrib/libs/cxxsupp/libcxx/include/vector b/contrib/libs/cxxsupp/libcxx/include/vector
index 916eaa75b63..1a2a271058b 100644
--- a/contrib/libs/cxxsupp/libcxx/include/vector
+++ b/contrib/libs/cxxsupp/libcxx/include/vector
@@ -637,7 +637,7 @@ public:
     _LIBCPP_INLINE_VISIBILITY iterator erase(const_iterator __position);
     iterator erase(const_iterator __first, const_iterator __last);
 
-    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_REINITIALIZES_OBJECT _LIBCPP_INLINE_VISIBILITY
     void clear() _NOEXCEPT
     {
         size_type __old_size = size();
@@ -2352,7 +2352,7 @@ public:
     _LIBCPP_INLINE_VISIBILITY iterator erase(const_iterator __position);
     iterator erase(const_iterator __first, const_iterator __last);
 
-    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_REINITIALIZES_OBJECT _LIBCPP_INLINE_VISIBILITY
     void clear() _NOEXCEPT {__size_ = 0;}
 
     void swap(vector&)
diff --git a/util/generic/buffer.h b/util/generic/buffer.h
index 95764674049..a5efe398ce7 100644
--- a/util/generic/buffer.h
+++ b/util/generic/buffer.h
@@ -4,6 +4,7 @@
 
 #include <util/generic/fwd.h>
 #include <util/system/align.h>
+#include <util/system/compiler.h>
 #include <util/system/yassert.h>
 
 #include <cstring>
@@ -46,7 +47,7 @@ public:
         Pos_ -= n;
     }
 
-    inline void Reset() noexcept {
+    Y_REINITIALIZES_OBJECT inline void Reset() noexcept {
         TBuffer().Swap(*this);
     }
 
diff --git a/util/generic/hash.h b/util/generic/hash.h
index 81311cc1ee4..0e2a7cfd12f 100644
--- a/util/generic/hash.h
+++ b/util/generic/hash.h
@@ -4,6 +4,7 @@
 #include "mapfindptr.h"
 
 #include <util/memory/alloc.h>
+#include <util/system/compiler.h>
 #include <util/system/type_name.h>
 #include <util/system/yassert.h>
 #include <util/str_stl.h>
@@ -820,7 +821,7 @@ public:
     void erase(const_iterator first, const_iterator last);
 
     bool reserve(size_type num_elements_hint);
-    void basic_clear();
+    Y_REINITIALIZES_OBJECT void basic_clear();
 
     /**
      * Clears the hashtable without deallocating the nodes.
@@ -841,7 +842,7 @@ public:
     template <class KeySaver>
     int save_for_st(IOutputStream* stream, KeySaver& ks, sthash<int, int, THash<int>, TEqualTo<int>, typename KeySaver::TSizeType>* stHash = nullptr) const;
 
-    void clear(size_type downsize) {
+    Y_REINITIALIZES_OBJECT void clear(size_type downsize) {
         basic_clear();
 
         if (downsize < buckets.size()) {
@@ -872,7 +873,7 @@ public:
      * Alternatively, the user can call `basic_clear`, which doesn't do the
      * downsizing.
      */
-    void clear() {
+    Y_REINITIALIZES_OBJECT void clear() {
         if (num_elements)
             clear((num_elements * 2 + buckets.size()) / 3);
     }
@@ -1715,13 +1716,13 @@ public:
     void erase(iterator f, iterator l) {
         rep.erase(f, l);
     }
-    void clear() {
+    Y_REINITIALIZES_OBJECT void clear() {
         rep.clear();
     }
-    void clear(size_t downsize_hint) {
+    Y_REINITIALIZES_OBJECT void clear(size_t downsize_hint) {
         rep.clear(downsize_hint);
     }
-    void basic_clear() {
+    Y_REINITIALIZES_OBJECT void basic_clear() {
         rep.basic_clear();
     }
     void release_nodes() {
@@ -1981,13 +1982,13 @@ public:
     void erase(iterator f, iterator l) {
         rep.erase(f, l);
     }
-    void clear() {
+    Y_REINITIALIZES_OBJECT void clear() {
         rep.clear();
     }
-    void clear(size_t downsize_hint) {
+    Y_REINITIALIZES_OBJECT void clear(size_t downsize_hint) {
         rep.clear(downsize_hint);
     }
-    void basic_clear() {
+    Y_REINITIALIZES_OBJECT void basic_clear() {
         rep.basic_clear();
     }
     void release_nodes() {
diff --git a/util/generic/hash_set.h b/util/generic/hash_set.h
index e8088cf23b4..fd8851c2993 100644
--- a/util/generic/hash_set.h
+++ b/util/generic/hash_set.h
@@ -3,6 +3,8 @@
 #include "fwd.h"
 #include "hash.h"
 
+#include <util/system/compiler.h>
+
 #include <initializer_list>
 #include <utility>
 
@@ -227,13 +229,13 @@ public:
     void erase(iterator f, iterator l) {
         rep.erase(f, l);
     }
-    void clear() {
+    Y_REINITIALIZES_OBJECT void clear() {
         rep.clear();
     }
-    void clear(size_t downsize_hint) {
+    Y_REINITIALIZES_OBJECT void clear(size_t downsize_hint) {
         rep.clear(downsize_hint);
     }
-    void basic_clear() {
+    Y_REINITIALIZES_OBJECT void basic_clear() {
         rep.basic_clear();
     }
     void release_nodes() {
@@ -435,13 +437,13 @@ public:
     void erase(iterator f, iterator l) {
         rep.erase(f, l);
     }
-    void clear() {
+    Y_REINITIALIZES_OBJECT void clear() {
         rep.clear();
     }
-    void clear(size_t downsize_hint) {
+    Y_REINITIALIZES_OBJECT void clear(size_t downsize_hint) {
         rep.clear(downsize_hint);
     }
-    void basic_clear() {
+    Y_REINITIALIZES_OBJECT void basic_clear() {
         rep.basic_clear();
     }
     void release_nodes() {
diff --git a/util/generic/maybe.h b/util/generic/maybe.h
index 34d21aebcdc..633eb1b8435 100644
--- a/util/generic/maybe.h
+++ b/util/generic/maybe.h
@@ -6,6 +6,7 @@
 #include "yexception.h"
 
 #include <util/system/align.h>
+#include <util/system/compiler.h>
 #include <util/stream/output.h>
 #include <util/ysaveload.h>
 
@@ -284,7 +285,7 @@ public:
         return *Data();
     }
 
-    void Clear() noexcept {
+    Y_REINITIALIZES_OBJECT void Clear() noexcept {
         if (Defined()) {
             this->Defined_ = false;
             Data()->~T();
diff --git a/util/generic/ptr.h b/util/generic/ptr.h
index db076e7e113..3addc85753e 100644
--- a/util/generic/ptr.h
+++ b/util/generic/ptr.h
@@ -9,8 +9,9 @@
 
 #include <utility>
 
-#include <util/system/yassert.h>
+#include <util/system/compiler.h>
 #include <util/system/defaults.h>
+#include <util/system/yassert.h>
 
 template <class T, class U>
 using TGuardConversion = typename std::enable_if_t<std::is_convertible<U*, T*>::value>;
@@ -189,14 +190,14 @@ public:
         return this->DoRelease(T_);
     }
 
-    inline void Reset(T* t) noexcept {
+    Y_REINITIALIZES_OBJECT inline void Reset(T* t) noexcept {
         if (T_ != t) {
             DoDestroy();
             T_ = t;
         }
     }
 
-    inline void Reset() noexcept {
+    Y_REINITIALIZES_OBJECT inline void Reset() noexcept {
         Destroy();
     }
 
@@ -284,18 +285,18 @@ public:
         return this->DoRelease(T_);
     }
 
-    inline void Reset(T* t) noexcept {
+    Y_REINITIALIZES_OBJECT inline void Reset(T* t) noexcept {
         if (T_ != t) {
             DoDestroy();
             T_ = t;
         }
     }
 
-    inline void Reset(TAutoPtr<T, D> t) noexcept {
+    Y_REINITIALIZES_OBJECT inline void Reset(TAutoPtr<T, D> t) noexcept {
         Reset(t.Release());
     }
 
-    inline void Reset() noexcept {
+    Y_REINITIALIZES_OBJECT inline void Reset() noexcept {
         Destroy();
     }
 
@@ -546,11 +547,11 @@ public:
     // Effectively replace both:
     // Reset(const TIntrusivePtr&)
     // Reset(TIntrusivePtr&&)
-    inline void Reset(TIntrusivePtr t) noexcept {
+    Y_REINITIALIZES_OBJECT inline void Reset(TIntrusivePtr t) noexcept {
         Swap(t);
     }
 
-    inline void Reset() noexcept {
+    Y_REINITIALIZES_OBJECT inline void Reset() noexcept {
         Drop();
     }
 
@@ -666,11 +667,11 @@ public:
     // Effectively replace both:
     // Reset(const TIntrusiveConstPtr&)
     // Reset(TIntrusiveConstPtr&&)
-    inline void Reset(TIntrusiveConstPtr t) noexcept {
+    Y_REINITIALIZES_OBJECT inline void Reset(TIntrusiveConstPtr t) noexcept {
         Swap(t);
     }
 
-    inline void Reset() noexcept {
+    Y_REINITIALIZES_OBJECT inline void Reset() noexcept {
         Drop();
     }
 
@@ -865,11 +866,11 @@ public:
     // Effectively replace both:
     // Reset(const TSharedPtr& t)
     // Reset(TSharedPtr&& t)
-    inline void Reset(TSharedPtr t) noexcept {
+    Y_REINITIALIZES_OBJECT inline void Reset(TSharedPtr t) noexcept {
         Swap(t);
     }
 
-    inline void Reset() noexcept {
+    Y_REINITIALIZES_OBJECT inline void Reset() noexcept {
         Drop();
     }
 
@@ -1015,14 +1016,14 @@ public:
         return DoRelease(T_);
     }
 
-    inline void Reset(T* t) noexcept {
+    Y_REINITIALIZES_OBJECT inline void Reset(T* t) noexcept {
         if (T_ != t) {
             DoDestroy();
             T_ = t;
         }
     }
 
-    inline void Reset() noexcept {
+    Y_REINITIALIZES_OBJECT inline void Reset() noexcept {
         Destroy();
     }
 
@@ -1094,11 +1095,11 @@ public:
         T_.Swap(r.T_);
     }
 
-    inline void Reset(TCowPtr p) {
+    Y_REINITIALIZES_OBJECT inline void Reset(TCowPtr p) {
         p.Swap(*this);
     }
 
-    inline void Reset() {
+    Y_REINITIALIZES_OBJECT inline void Reset() {
         T_.Reset();
     }
 
diff --git a/util/generic/string.h b/util/generic/string.h
index fedde9e787d..5f569544816 100644
--- a/util/generic/string.h
+++ b/util/generic/string.h
@@ -8,6 +8,7 @@
 #include <string>
 #include <string_view>
 
+#include <util/system/compiler.h>
 #include <util/system/yassert.h>
 
 #include "ptr.h"
@@ -561,7 +562,7 @@ private:
     }
 
 public:
-    inline void clear() noexcept {
+    Y_REINITIALIZES_OBJECT inline void clear() noexcept {
 #ifdef TSTRING_IS_STD_STRING
         Storage_.clear();
 #else
diff --git a/util/system/compiler.h b/util/system/compiler.h
index ba8ea4e3b70..d2054465977 100644
--- a/util/system/compiler.h
+++ b/util/system/compiler.h
@@ -636,6 +636,12 @@ _YandexAbort();
         } while (0)
 #endif
 
+#if defined(__clang__)
+    #define Y_REINITIALIZES_OBJECT [[clang::reinitializes]]
+#else
+    #define Y_REINITIALIZES_OBJECT
+#endif
+
 #ifdef __cplusplus
 
 void UseCharPointerImpl(volatile const char*);