Library import 8 (#1074)

* Library import 8

* Add contrib/libs/cxxsupp/libcxx/include/__verbose_abort

24 files changed, 316 insertions, 64 deletions

diff --git a/library/cpp/http/fetch/exthttpcodes.h b/library/cpp/http/fetch/exthttpcodes.h
index 49e7e5e62d..764e637fee 100644
--- a/library/cpp/http/fetch/exthttpcodes.h
+++ b/library/cpp/http/fetch/exthttpcodes.h
@@ -50,6 +50,7 @@ enum ExtHttpCodes {
     HTTP_FETCHER_MB_ERROR = 1041,
     HTTP_SSL_CERT_ERROR = 1042,
     HTTP_FIREWALL_REJECT = 1043,
+    HTTP_INTERNAL_DNS_ERROR = 1047,
     HTTP_PROXY_REQUEST_CANCELED = 1051,
 
     // Custom (replace HTTP 200/304)
diff --git a/library/cpp/http/fetch/http_digest.cpp b/library/cpp/http/fetch/http_digest.cpp
index 4dff4b047d..5adf391709 100644
--- a/library/cpp/http/fetch/http_digest.cpp
+++ b/library/cpp/http/fetch/http_digest.cpp
@@ -47,21 +47,19 @@ const char* httpDigestHandler::getHeaderInstruction() const {
 }
 
 /************************************************************/
-void httpDigestHandler::generateCNonce(char* outCNonce) {
-    if (!*outCNonce)
-        sprintf(outCNonce, "%ld", (long)time(nullptr));
-}
-
-/************************************************************/
-inline void addMD5(MD5& ctx, const char* value) {
+Y_FORCE_INLINE void addMD5(MD5& ctx, const char* value) {
     ctx.Update((const unsigned char*)(value), strlen(value));
 }
 
-inline void addMD5(MD5& ctx, const char* value, int len) {
+Y_FORCE_INLINE void addMD5(MD5& ctx, const char* value, int len) {
     ctx.Update((const unsigned char*)(value), len);
 }
 
-inline void addMD5Sep(MD5& ctx) {
+Y_FORCE_INLINE void addMD5(MD5& ctx, std::string_view str) {
+    ctx.Update(str);
+}
+
+Y_FORCE_INLINE void addMD5Sep(MD5& ctx) {
     addMD5(ctx, ":", 1);
 }
 
@@ -69,7 +67,7 @@ inline void addMD5Sep(MD5& ctx) {
 /* calculate H(A1) as per spec */
 void httpDigestHandler::digestCalcHA1(const THttpAuthHeader& hd,
                                       char* outSessionKey,
-                                      char* outCNonce) {
+                                      const std::string& outCNonce) {
     MD5 ctx;
     ctx.Init();
     addMD5(ctx, User_);
@@ -82,8 +80,6 @@ void httpDigestHandler::digestCalcHA1(const THttpAuthHeader& hd,
         unsigned char digest[16];
         ctx.Final(digest);
 
-        generateCNonce(outCNonce);
-
         ctx.Init();
         ctx.Update(digest, 16);
         addMD5Sep(ctx);
@@ -103,7 +99,7 @@ void httpDigestHandler::digestCalcResponse(const THttpAuthHeader& hd,
                                            const char* method,
                                            const char* nonceCount,
                                            char* outResponse,
-                                           char* outCNonce) {
+                                           const std::string& outCNonce) {
     char HA1[33];
     digestCalcHA1(hd, HA1, outCNonce);
 
@@ -123,9 +119,6 @@ void httpDigestHandler::digestCalcResponse(const THttpAuthHeader& hd,
     addMD5Sep(ctx);
 
     if (hd.qop_auth) {
-        if (!*outCNonce)
-            generateCNonce(outCNonce);
-
         addMD5(ctx, nonceCount, 8);
         addMD5Sep(ctx);
         addMD5(ctx, outCNonce);
@@ -141,7 +134,7 @@ void httpDigestHandler::digestCalcResponse(const THttpAuthHeader& hd,
 bool httpDigestHandler::processHeader(const THttpAuthHeader* header,
                                       const char* path,
                                       const char* method,
-                                      const char* cnonce) {
+                                      const char* cnonceIn) {
     if (!User_ || !header || !header->use_auth || !header->realm || !header->nonce)
         return false;
 
@@ -161,16 +154,12 @@ bool httpDigestHandler::processHeader(const THttpAuthHeader* header,
     NonceCount_++;
 
     char nonceCount[20];
-    sprintf(nonceCount, "%08d", NonceCount_);
+    snprintf(nonceCount, sizeof(nonceCount), "%08d", NonceCount_);
 
-    char CNonce[50];
-    if (cnonce)
-        strcpy(CNonce, cnonce);
-    else
-        CNonce[0] = 0;
+    std::string cNonce = cnonceIn ? std::string(cnonceIn) : std::to_string(time(nullptr));
 
     char response[33];
-    digestCalcResponse(*header, path, method, nonceCount, response, CNonce);
+    digestCalcResponse(*header, path, method, nonceCount, response, cNonce);
 
     //digest-response  = 1#( username | realm | nonce | digest-uri
     //                   | response | [ algorithm ] | [cnonce] |
@@ -189,8 +178,8 @@ bool httpDigestHandler::processHeader(const THttpAuthHeader* header,
     if (header->qop_auth)
         out << ", qop=auth";
     out << ", nc=" << nonceCount;
-    if (CNonce[0])
-        out << ", cnonce=\"" << CNonce << "\"";
+    if (!cNonce.empty())
+        out << ", cnonce=\"" << cNonce << "\"";
     out << ", response=\"" << response << "\"";
     if (header->opaque)
         out << ", opaque=\"" << header->opaque << "\"";
diff --git a/library/cpp/http/fetch/http_digest.h b/library/cpp/http/fetch/http_digest.h
index 3b1872d70b..e5ffa3c69e 100644
--- a/library/cpp/http/fetch/http_digest.h
+++ b/library/cpp/http/fetch/http_digest.h
@@ -2,11 +2,13 @@
 
 #include "httpheader.h"
 
+#include <string>
+
 #include <util/system/compat.h>
 #include <library/cpp/http/misc/httpcodes.h>
 
 class httpDigestHandler {
-protected:
+private:
     const char* User_;
     const char* Password_;
     char* Nonce_;
@@ -15,18 +17,16 @@ protected:
 
     void clear();
 
-    void generateCNonce(char* outCNonce);
-
     void digestCalcHA1(const THttpAuthHeader& hd,
                        char* outSessionKey,
-                       char* outCNonce);
+                       const std::string& outCNonce);
 
     void digestCalcResponse(const THttpAuthHeader& hd,
                             const char* method,
                             const char* path,
                             const char* nonceCount,
                             char* outResponse,
-                            char* outCNonce);
+                            const std::string& outCNonce);
 
 public:
     httpDigestHandler();
diff --git a/library/cpp/http/fetch/httpagent.h b/library/cpp/http/fetch/httpagent.h
index c66af00ced..18f10c160e 100644
--- a/library/cpp/http/fetch/httpagent.h
+++ b/library/cpp/http/fetch/httpagent.h
@@ -172,9 +172,9 @@ public:
             Hostheader = (char*)malloc((HostheaderLen = reqHostheaderLen));
         }
         if (port == 80)
-            sprintf(Hostheader, "Host: %s\r\n", hostname);
+            snprintf(Hostheader, HostheaderLen, "Host: %s\r\n", hostname);
         else
-            sprintf(Hostheader, "Host: %s:%u\r\n", hostname, port);
+            snprintf(Hostheader, HostheaderLen, "Host: %s:%u\r\n", hostname, port);
         pHostBeg = strchr(Hostheader, ' ') + 1;
         pHostEnd = strchr(pHostBeg, '\r');
         // convert hostname to lower case since some web server don't like
@@ -195,7 +195,7 @@ public:
             delete[] Hostheader;
             Hostheader = new char[(HostheaderLen = reqHostheaderLen)];
         }
-        sprintf(Hostheader, "Host: %s\r\n", host);
+        snprintf(Hostheader, HostheaderLen, "Host: %s\r\n", host);
     }
 
     void SetSocket(SOCKET fd) {
diff --git a/library/cpp/http/fetch/httpload.cpp b/library/cpp/http/fetch/httpload.cpp
index f3f6c5245e..65631203e5 100644
--- a/library/cpp/http/fetch/httpload.cpp
+++ b/library/cpp/http/fetch/httpload.cpp
@@ -259,9 +259,10 @@ bool httpLoadAgent::doSetHost(const TAddrList& addrs) {
         return false;
 
     if (RealHost_) {
+        size_t reqHostheaderLen = strlen(RealHost_) + 20;
         free(Hostheader);
-        Hostheader = (char*)malloc(strlen(RealHost_) + 20);
-        sprintf(Hostheader, "Host: %s\r\n", RealHost_);
+        Hostheader = (char*)malloc((HostheaderLen = reqHostheaderLen));
+        snprintf(Hostheader, HostheaderLen, "Host: %s\r\n", RealHost_);
     }
 
     if (!URL_.IsNull(THttpURL::FlagAuth)) {
diff --git a/library/cpp/unified_agent_client/client.h b/library/cpp/unified_agent_client/client.h
index 62e1210803..e58ffc8b11 100644
--- a/library/cpp/unified_agent_client/client.h
+++ b/library/cpp/unified_agent_client/client.h
@@ -40,8 +40,8 @@ namespace NUnifiedAgent {
         // TLog instance for client library's own logs.
         //
         // Default: TLoggerOperator<TGlobalLog>::Log()
-        TClientParameters& SetLog(TLog& log) {
-            Log = log;
+        TClientParameters& SetLog(TLog log) {
+            Log = std::move(log);
             return *this;
         }
 
diff --git a/library/cpp/yt/memory/blob.h b/library/cpp/yt/memory/blob.h
index 0a1318c231..42cab83017 100644
--- a/library/cpp/yt/memory/blob.h
+++ b/library/cpp/yt/memory/blob.h
@@ -3,6 +3,8 @@
 #include "ref.h"
 #include "ref_counted.h"
 
+#include <library/cpp/yt/misc/port.h>
+
 namespace NYT {
 
 ////////////////////////////////////////////////////////////////////////////////
diff --git a/library/cpp/yt/memory/chunked_memory_pool.h b/library/cpp/yt/memory/chunked_memory_pool.h
index a22e2ec27c..d5771480ac 100644
--- a/library/cpp/yt/memory/chunked_memory_pool.h
+++ b/library/cpp/yt/memory/chunked_memory_pool.h
@@ -3,6 +3,8 @@
 #include "public.h"
 #include "ref.h"
 
+#include <library/cpp/yt/misc/port.h>
+
 #include <util/generic/size_literals.h>
 
 namespace NYT {
diff --git a/library/cpp/yt/memory/intrusive_ptr.h b/library/cpp/yt/memory/intrusive_ptr.h
index 1da3b06966..91b15279ae 100644
--- a/library/cpp/yt/memory/intrusive_ptr.h
+++ b/library/cpp/yt/memory/intrusive_ptr.h
@@ -55,7 +55,7 @@ public:
         : T_(other.Get())
     {
         static_assert(
-            std::is_base_of_v<TRefCountedBase, T>,
+            std::derived_from<T, TRefCountedBase>,
             "Cast allowed only for types derived from TRefCountedBase");
         if (T_) {
             Ref(T_);
@@ -75,7 +75,7 @@ public:
         : T_(other.Get())
     {
         static_assert(
-            std::is_base_of_v<TRefCountedBase, T>,
+            std::derived_from<T, TRefCountedBase>,
             "Cast allowed only for types derived from TRefCountedBase");
         other.T_ = nullptr;
     }
@@ -103,7 +103,7 @@ public:
             std::is_convertible_v<U*, T*>,
             "U* must be convertible to T*");
         static_assert(
-            std::is_base_of_v<TRefCountedBase, T>,
+            std::derived_from<T, TRefCountedBase>,
             "Cast allowed only for types derived from TRefCountedBase");
         TIntrusivePtr(other).Swap(*this);
         return *this;
@@ -124,7 +124,7 @@ public:
             std::is_convertible_v<U*, T*>,
             "U* must be convertible to T*");
         static_assert(
-            std::is_base_of_v<TRefCountedBase, T>,
+            std::derived_from<T, TRefCountedBase>,
             "Cast allowed only for types derived from TRefCountedBase");
         TIntrusivePtr(std::move(other)).Swap(*this);
         return *this;
diff --git a/library/cpp/yt/memory/new-inl.h b/library/cpp/yt/memory/new-inl.h
index 53adaecdc0..c21bd37a0c 100644
--- a/library/cpp/yt/memory/new-inl.h
+++ b/library/cpp/yt/memory/new-inl.h
@@ -6,6 +6,8 @@
 
 #include "ref_tracked.h"
 
+#include <library/cpp/yt/misc/port.h>
+
 #include <library/cpp/yt/malloc//malloc.h>
 
 namespace NYT {
@@ -121,7 +123,7 @@ Y_FORCE_INLINE T* NewEpilogue(void* ptr, As&& ... args)
     }
 }
 
-template <class T, bool = std::is_base_of_v<TRefCountedBase, T>>
+template <class T, bool = std::derived_from<T, TRefCountedBase>>
 struct TConstructHelper
 {
     static constexpr size_t RefCounterSpace = (sizeof(TRefCounter) + alignof(T) - 1) & ~(alignof(T) - 1);
diff --git a/library/cpp/yt/memory/ref.cpp b/library/cpp/yt/memory/ref.cpp
index 605bc4ae2e..b5b636c9db 100644
--- a/library/cpp/yt/memory/ref.cpp
+++ b/library/cpp/yt/memory/ref.cpp
@@ -4,6 +4,8 @@
 
 #include <library/cpp/yt/malloc/malloc.h>
 
+#include <library/cpp/yt/misc/port.h>
+
 #include <util/system/info.h>
 #include <util/system/align.h>
 
diff --git a/library/cpp/yt/memory/ref_counted-inl.h b/library/cpp/yt/memory/ref_counted-inl.h
index fcd64abb17..f86f634ffd 100644
--- a/library/cpp/yt/memory/ref_counted-inl.h
+++ b/library/cpp/yt/memory/ref_counted-inl.h
@@ -103,7 +103,7 @@ Y_FORCE_INLINE void DestroyRefCountedImpl(T* obj)
 ////////////////////////////////////////////////////////////////////////////////
 
 // Specialization for final classes.
-template <class T, bool = std::is_base_of_v<TRefCountedBase, T>>
+template <class T, bool = std::derived_from<T, TRefCountedBase>>
 struct TRefCountedTraits
 {
     static_assert(
diff --git a/library/cpp/yt/memory/weak_ptr.h b/library/cpp/yt/memory/weak_ptr.h
index a5a7f0a525..c647198aaf 100644
--- a/library/cpp/yt/memory/weak_ptr.h
+++ b/library/cpp/yt/memory/weak_ptr.h
@@ -48,7 +48,7 @@ public:
         : TWeakPtr(ptr.Get())
     {
         static_assert(
-            std::is_base_of_v<TRefCountedBase, T>,
+            std::derived_from<T, TRefCountedBase>,
             "Cast allowed only for types derived from TRefCountedBase");
     }
 
@@ -63,7 +63,7 @@ public:
         : TWeakPtr(other.Lock())
     {
         static_assert(
-            std::is_base_of_v<TRefCountedBase, T>,
+            std::derived_from<T, TRefCountedBase>,
             "Cast allowed only for types derived from TRefCountedBase");
     }
 
@@ -78,7 +78,7 @@ public:
     TWeakPtr(TWeakPtr<U>&& other) noexcept
     {
         static_assert(
-            std::is_base_of_v<TRefCountedBase, T>,
+            std::derived_from<T, TRefCountedBase>,
             "Cast allowed only for types derived from TRefCountedBase");
         TIntrusivePtr<U> strongOther = other.Lock();
         if (strongOther) {
diff --git a/library/cpp/yt/misc/strong_typedef-inl.h b/library/cpp/yt/misc/strong_typedef-inl.h
index 09b814b62c..0e9adee186 100644
--- a/library/cpp/yt/misc/strong_typedef-inl.h
+++ b/library/cpp/yt/misc/strong_typedef-inl.h
@@ -170,8 +170,55 @@ struct hash<NYT::TStrongTypedef<T, TTag>>
 template <class T, class TTag>
     requires std::numeric_limits<T>::is_specialized
 class numeric_limits<NYT::TStrongTypedef<T, TTag>>
-    : public numeric_limits<T>
-{ };
+{
+public:
+    #define XX(name) \
+        static constexpr decltype(numeric_limits<T>::name) name = numeric_limits<T>::name;
+
+    XX(is_specialized)
+    XX(is_signed)
+    XX(digits)
+    XX(digits10)
+    XX(max_digits10)
+    XX(is_integer)
+    XX(is_exact)
+    XX(radix)
+    XX(min_exponent)
+    XX(min_exponent10)
+    XX(max_exponent)
+    XX(max_exponent10)
+    XX(has_infinity)
+    XX(has_quiet_NaN)
+    XX(has_signaling_NaN)
+    XX(has_denorm)
+    XX(has_denorm_loss)
+    XX(is_iec559)
+    XX(is_bounded)
+    XX(is_modulo)
+    XX(traps)
+    XX(tinyness_before)
+    XX(round_style)
+
+    #undef XX
+
+    #define XX(name) \
+        static constexpr NYT::TStrongTypedef<T, TTag> name() noexcept \
+        { \
+            return NYT::TStrongTypedef<T, TTag>(numeric_limits<T>::name()); \
+        }
+
+    XX(min)
+    XX(max)
+    XX(lowest)
+    XX(epsilon)
+    XX(round_error)
+    XX(infinity)
+    XX(quiet_NaN)
+    XX(signaling_NaN)
+    XX(denorm_min)
+
+    #undef XX
+};
 
 ////////////////////////////////////////////////////////////////////////////////
 
diff --git a/library/cpp/yt/misc/unittests/strong_typedef_ut.cpp b/library/cpp/yt/misc/unittests/strong_typedef_ut.cpp
index bc9321bb3c..1a06cc3c8b 100644
--- a/library/cpp/yt/misc/unittests/strong_typedef_ut.cpp
+++ b/library/cpp/yt/misc/unittests/strong_typedef_ut.cpp
@@ -43,8 +43,8 @@ XX(round_style)
 #undef XX
 
 #define XX(name) \
-    static_assert(std::numeric_limits<TMyInt1>::name() == std::numeric_limits<int>::name()); \
-    static_assert(std::numeric_limits<TMyInt2>::name() == std::numeric_limits<int>::name());
+    static_assert(std::numeric_limits<TMyInt1>::name() == TMyInt1(std::numeric_limits<int>::name())); \
+    static_assert(std::numeric_limits<TMyInt2>::name() == TMyInt2(TMyInt1(std::numeric_limits<int>::name())));
 
 XX(min)
 XX(max)
diff --git a/library/cpp/yt/threading/fork_aware_spin_lock.h b/library/cpp/yt/threading/fork_aware_spin_lock.h
index 1d69aa1bca..215fb58dc9 100644
--- a/library/cpp/yt/threading/fork_aware_spin_lock.h
+++ b/library/cpp/yt/threading/fork_aware_spin_lock.h
@@ -30,7 +30,7 @@ public:
     bool IsLocked() const noexcept;
 
 private:
-    TSpinLock SpinLock_;
+    ::TSpinLock SpinLock_;
 };
 
 ////////////////////////////////////////////////////////////////////////////////
diff --git a/library/python/svn_version/__init__.py b/library/python/svn_version/__init__.py
index caaef65bfe..b5c05d6bc0 100644
--- a/library/python/svn_version/__init__.py
+++ b/library/python/svn_version/__init__.py
@@ -1,5 +1,25 @@
-from .__svn_version import svn_version, commit_id, svn_revision, svn_last_revision, hash, svn_branch, svn_tag, patch_number, vcs, svn_timestamp
+from .__svn_version import (
+    svn_version,
+    commit_id,
+    svn_revision,
+    svn_last_revision,
+    hash,
+    svn_branch,
+    svn_tag,
+    patch_number,
+    vcs,
+    svn_timestamp,
+)
 
 __all__ = (
-    'svn_version', 'commit_id', 'svn_revision', 'svn_last_revision', 'hash', 'svn_branch', 'svn_tag', 'patch_number', 'vcs', 'svn_timestamp'
+    'svn_version',
+    'commit_id',
+    'svn_revision',
+    'svn_last_revision',
+    'hash',
+    'svn_branch',
+    'svn_tag',
+    'patch_number',
+    'vcs',
+    'svn_timestamp',
 )
diff --git a/library/python/svn_version/ut/test_simple.py b/library/python/svn_version/ut/test_simple.py
new file mode 100644
index 0000000000..50fa78f55d
--- /dev/null
+++ b/library/python/svn_version/ut/test_simple.py
@@ -0,0 +1,24 @@
+import library.python.svn_version as sv
+
+
+def test_simple():
+    assert sv.svn_version()
+    assert isinstance(sv.svn_version(), str)
+
+    assert sv.vcs()
+    assert isinstance(sv.vcs(), str)
+
+    # svn_revision() will be -1 on non-trunk commits via arc
+    # svn revision of 0 technically may exist, but practiacally it will never appear here
+    assert sv.svn_revision() >= 0 or (sv.vcs() != "svn" and sv.svn_revision() == -1)
+    assert isinstance(sv.svn_revision(), int)
+
+    # svn_last_revision() will be equal to zero on non-trunk commits
+    assert sv.svn_last_revision() >= 0 or (sv.vcs() != "svn" and sv.svn_last_revision() == -1)
+    assert isinstance(sv.svn_last_revision(), int)
+
+    assert sv.commit_id()
+    assert isinstance(sv.commit_id(), str)
+    assert len(sv.commit_id()) > 0
+    assert isinstance(sv.hash(), str)
+    assert isinstance(sv.patch_number(), int)
diff --git a/library/python/svn_version/ut/ya.make b/library/python/svn_version/ut/ya.make
new file mode 100644
index 0000000000..c96b843565
--- /dev/null
+++ b/library/python/svn_version/ut/ya.make
@@ -0,0 +1,13 @@
+PY23_TEST()
+
+STYLE_PYTHON()
+
+PEERDIR(
+    library/python/svn_version
+)
+
+TEST_SRCS(
+    test_simple.py
+)
+
+END()
diff --git a/library/python/svn_version/ya.make b/library/python/svn_version/ya.make
index f168ea4a94..8fdcd50819 100644
--- a/library/python/svn_version/ya.make
+++ b/library/python/svn_version/ya.make
@@ -1,5 +1,7 @@
 PY23_LIBRARY()
 
+STYLE_PYTHON()
+
 PEERDIR(
     library/cpp/svnversion
     contrib/python/future
@@ -11,3 +13,7 @@ PY_SRCS(
 )
 
 END()
+
+RECURSE_FOR_TESTS(
+    ut
+)
diff --git a/library/python/windows/__init__.py b/library/python/windows/__init__.py
index eb520a8d2d..fe7a2c0140 100644
--- a/library/python/windows/__init__.py
+++ b/library/python/windows/__init__.py
@@ -191,7 +191,9 @@ if on_win():
     def transcode_error(windows_error, to_enc='utf-8'):
         from_enc = 'utf-8' if getattr(windows_error, 'utf8', False) else library.python.strings.guess_default_encoding()
         if from_enc != to_enc:
-            windows_error.strerror = library.python.strings.to_str(windows_error.strerror, to_enc=to_enc, from_enc=from_enc)
+            windows_error.strerror = library.python.strings.to_str(
+                windows_error.strerror, to_enc=to_enc, from_enc=from_enc
+            )
         setattr(windows_error, 'utf8', to_enc == 'utf-8')
 
     class Transaction(object):
@@ -230,14 +232,26 @@ if on_win():
     @win_only
     @require_ctypes
     def replace_file(src, dst):
-        if not ctypes.windll.kernel32.MoveFileExW(unicode_path(src), unicode_path(dst), _MOVEFILE_REPLACE_EXISTING | _MOVEFILE_WRITE_THROUGH):
+        if not ctypes.windll.kernel32.MoveFileExW(
+            unicode_path(src), unicode_path(dst), _MOVEFILE_REPLACE_EXISTING | _MOVEFILE_WRITE_THROUGH
+        ):
             raise ctypes.WinError()
 
     @win_only
     @require_ctypes
     def replace_file_across_devices(src, dst):
-        with Transaction(timeout=_ATOMIC_RENAME_FILE_TRANSACTION_DEFAULT_TIMEOUT, description='ya library.python.windows replace_file_across_devices') as transaction:
-            if not ctypes.windll.kernel32.MoveFileTransactedW(unicode_path(src), unicode_path(dst), None, None, _MOVEFILE_REPLACE_EXISTING | _MOVEFILE_WRITE_THROUGH, transaction):
+        with Transaction(
+            timeout=_ATOMIC_RENAME_FILE_TRANSACTION_DEFAULT_TIMEOUT,
+            description='ya library.python.windows replace_file_across_devices',
+        ) as transaction:
+            if not ctypes.windll.kernel32.MoveFileTransactedW(
+                unicode_path(src),
+                unicode_path(dst),
+                None,
+                None,
+                _MOVEFILE_REPLACE_EXISTING | _MOVEFILE_WRITE_THROUGH,
+                transaction,
+            ):
                 raise ctypes.WinError()
 
     @win_only
@@ -259,13 +273,17 @@ if on_win():
     @win_disabled
     @require_ctypes
     def symlink_dir(src, lnk):
-        if not ctypes.windll.kernel32.CreateSymbolicLinkW(unicode_path(lnk), unicode_path(src), _SYMBOLIC_LINK_FLAG_DIRECTORY):
+        if not ctypes.windll.kernel32.CreateSymbolicLinkW(
+            unicode_path(lnk), unicode_path(src), _SYMBOLIC_LINK_FLAG_DIRECTORY
+        ):
             raise ctypes.WinError()
 
     @win_only
     @require_ctypes
     def lock_file(f, offset, length, raises=True):
-        locked = ctypes.windll.kernel32.LockFile(file_handle(f), _low_dword(offset), _high_dword(offset), _low_dword(length), _high_dword(length))
+        locked = ctypes.windll.kernel32.LockFile(
+            file_handle(f), _low_dword(offset), _high_dword(offset), _low_dword(length), _high_dword(length)
+        )
         if not raises:
             return bool(locked)
         if not locked:
@@ -274,7 +292,9 @@ if on_win():
     @win_only
     @require_ctypes
     def unlock_file(f, offset, length, raises=True):
-        unlocked = ctypes.windll.kernel32.UnlockFile(file_handle(f), _low_dword(offset), _high_dword(offset), _low_dword(length), _high_dword(length))
+        unlocked = ctypes.windll.kernel32.UnlockFile(
+            file_handle(f), _low_dword(offset), _high_dword(offset), _low_dword(length), _high_dword(length)
+        )
         if not raises:
             return bool(unlocked)
         if not unlocked:
@@ -304,6 +324,7 @@ if on_win():
                     # propagate true last error if this attempt fails
                     return func(handling_path)
             raise e
+
         shutil.rmtree(path, onerror=error_handler)
 
     # Don't display the Windows GPF dialog if the invoked program dies.
@@ -337,7 +358,9 @@ if on_win():
     def get_process_handle_count(proc_handle):
         assert isinstance(proc_handle, wintypes.HANDLE)
 
-        GetProcessHandleCount = ctypes.WINFUNCTYPE(wintypes.BOOL, wintypes.HANDLE, wintypes.POINTER(wintypes.DWORD))(("GetProcessHandleCount", ctypes.windll.kernel32))
+        GetProcessHandleCount = ctypes.WINFUNCTYPE(wintypes.BOOL, wintypes.HANDLE, wintypes.POINTER(wintypes.DWORD))(
+            ("GetProcessHandleCount", ctypes.windll.kernel32)
+        )
         hndcnt = wintypes.DWORD()
         if not GetProcessHandleCount(proc_handle, ctypes.byref(hndcnt)):
             raise ctypes.WinError()
@@ -349,7 +372,9 @@ if on_win():
         for flag, value in [(inherit, 1), (protect_from_close, 2)]:
             if flag is not None:
                 assert isinstance(flag, bool)
-                if not ctypes.windll.kernel32.SetHandleInformation(file_handle(file), _low_dword(value), _low_dword(int(flag))):
+                if not ctypes.windll.kernel32.SetHandleInformation(
+                    file_handle(file), _low_dword(value), _low_dword(int(flag))
+                ):
                     raise ctypes.WinError()
 
     @win_only
diff --git a/library/python/windows/ut/test_windows.py b/library/python/windows/ut/test_windows.py
new file mode 100644
index 0000000000..beaa5fc3aa
--- /dev/null
+++ b/library/python/windows/ut/test_windows.py
@@ -0,0 +1,97 @@
+# coding=utf-8
+
+import errno
+import os
+import pytest
+import six
+
+import library.python.strings
+import library.python.windows
+
+
+def gen_error_access_denied():
+    if library.python.windows.on_win():
+        err = WindowsError()
+        err.errno = errno.EACCES
+        err.strerror = ''
+        err.winerror = library.python.windows.ERRORS['ACCESS_DENIED']
+    else:
+        err = OSError()
+        err.errno = errno.EACCES
+        err.strerror = os.strerror(err.errno)
+    err.filename = 'unknown/file'
+    raise err
+
+
+def test_errorfix_buggy():
+    @library.python.windows.errorfix
+    def erroneous_func():
+        gen_error_access_denied()
+
+    with pytest.raises(OSError) as errinfo:
+        erroneous_func()
+    assert errinfo.value.errno == errno.EACCES
+    assert errinfo.value.filename == 'unknown/file'
+    assert isinstance(errinfo.value.strerror, six.string_types)
+    assert errinfo.value.strerror
+
+
+def test_errorfix_explicit():
+    @library.python.windows.errorfix
+    def erroneous_func():
+        if library.python.windows.on_win():
+            err = WindowsError()
+            err.winerror = library.python.windows.ERRORS['ACCESS_DENIED']
+        else:
+            err = OSError()
+        err.errno = errno.EACCES
+        err.strerror = 'Some error description'
+        err.filename = 'unknown/file'
+        raise err
+
+    with pytest.raises(OSError) as errinfo:
+        erroneous_func()
+    assert errinfo.value.errno == errno.EACCES
+    assert errinfo.value.filename == 'unknown/file'
+    assert errinfo.value.strerror == 'Some error description'
+
+
+def test_errorfix_decoding_cp1251():
+    @library.python.windows.errorfix
+    def erroneous_func():
+        model_msg = u'Какое-то описание ошибки'
+        if library.python.windows.on_win():
+            err = WindowsError()
+            err.strerror = library.python.strings.to_str(model_msg, 'cp1251')
+        else:
+            err = OSError()
+            err.strerror = library.python.strings.to_str(model_msg)
+        raise err
+
+    with pytest.raises(OSError) as errinfo:
+        erroneous_func()
+    error_msg = errinfo.value.strerror
+    if not isinstance(errinfo.value.strerror, six.text_type):
+        error_msg = library.python.strings.to_unicode(error_msg)
+    assert error_msg == u'Какое-то описание ошибки'
+
+
+def test_diehard():
+    @library.python.windows.diehard(library.python.windows.ERRORS['ACCESS_DENIED'], tries=5)
+    def erroneous_func(errors):
+        try:
+            gen_error_access_denied()
+        except Exception as e:
+            errors.append(e)
+            raise
+
+    raised_errors = []
+    with pytest.raises(OSError) as errinfo:
+        erroneous_func(raised_errors)
+    assert errinfo.value.errno == errno.EACCES
+    assert any(e.errno == errno.EACCES for e in raised_errors)
+    assert raised_errors and errinfo.value == raised_errors[-1]
+    if library.python.windows.on_win():
+        assert len(raised_errors) == 5
+    else:
+        assert len(raised_errors) == 1
diff --git a/library/python/windows/ut/ya.make b/library/python/windows/ut/ya.make
new file mode 100644
index 0000000000..c321141f37
--- /dev/null
+++ b/library/python/windows/ut/ya.make
@@ -0,0 +1,13 @@
+PY23_TEST()
+
+STYLE_PYTHON()
+
+TEST_SRCS(
+    test_windows.py
+)
+
+PEERDIR(
+    library/python/windows
+)
+
+END()
diff --git a/library/python/windows/ya.make b/library/python/windows/ya.make
index 97c6f48f23..14f7dfac71 100644
--- a/library/python/windows/ya.make
+++ b/library/python/windows/ya.make
@@ -1,6 +1,10 @@
 PY23_LIBRARY()
 
-PY_SRCS(__init__.py)
+STYLE_PYTHON()
+
+PY_SRCS(
+    __init__.py
+)
 
 PEERDIR(
     library/python/func
@@ -9,3 +13,7 @@ PEERDIR(
 )
 
 END()
+
+RECURSE_FOR_TESTS(
+    ut
+)