From 32e124ee0a520e1697b01c9cc2dbd08ddbc18756 Mon Sep 17 00:00:00 2001
From: Bulat <bulat@ydb.tech>
Date: Tue, 3 Sep 2024 16:03:51 +0300
Subject: [PATCH] Fixed util test string_transparent_hash_ut (#311)

---
 util/CMakeLists.txt                         |  3 +--
 util/generic/string_transparent_hash_ut.cpp | 20 ++++++++++++++++----
 2 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/util/CMakeLists.txt b/util/CMakeLists.txt
index 994e5163a2c..9220b75b740 100644
--- a/util/CMakeLists.txt
+++ b/util/CMakeLists.txt
@@ -96,8 +96,7 @@ if (YDB_SDK_TESTS)
       generic/stack_ut.cpp
       generic/store_policy_ut.cpp
       generic/strbuf_ut.cpp
-      # TODO: uncomment this test after we get the fix
-      # generic/string_transparent_hash_ut.cpp
+      generic/string_transparent_hash_ut.cpp
       generic/string_ut.cpp
       generic/typelist_ut.cpp
       generic/typetraits_ut.cpp
diff --git a/util/generic/string_transparent_hash_ut.cpp b/util/generic/string_transparent_hash_ut.cpp
index b87fa2843e6..a03fc7e6d7d 100644
--- a/util/generic/string_transparent_hash_ut.cpp
+++ b/util/generic/string_transparent_hash_ut.cpp
@@ -3,15 +3,27 @@
 #include "strbuf.h"
 
 #include <library/cpp/testing/unittest/registar.h>
-#include <library/cpp/containers/absl_flat_hash/flat_hash_set.h>
 
 #include <util/str_stl.h>
 
+#ifdef __cpp_lib_generic_unordered_lookup
+    #include <unordered_set>
+
+template <class T, class THasher, class TPred>
+using THashSetType = std::unordered_set<T, THasher, TPred>;
+#else
+    // Using Abseil hash set because `std::unordered_set` is transparent only from libstdc++11.
+    // Meanwhile clang-linux-x86_64-release-stl-system autocheck sets OS_SDK=ubuntu-20,
+    // that support libstdc++10 by default.
+    #include <library/cpp/containers/absl_flat_hash/flat_hash_set.h>
+
+template <class T, class THasher, class TPred>
+using THashSetType = absl::flat_hash_set<T, THasher, TPred>;
+#endif
+
 Y_UNIT_TEST_SUITE(StringHashFunctorTests) {
     Y_UNIT_TEST(TestTransparencyWithUnorderedSet) {
-        // Using Abseil hash set because `std::unordered_set` is transparent only from C++20 (while
-        // we stuck with C++17 right now).
-        absl::flat_hash_set<TString, THash<TString>, TEqualTo<TString>> s = {"foo"};
+        THashSetType<TString, THash<TString>, TEqualTo<TString>> s = {"foo"};
         // If either `THash` or `TEqualTo` is not transparent compilation will fail.
         UNIT_ASSERT_UNEQUAL(s.find(TStringBuf("foo")), s.end());
         UNIT_ASSERT_EQUAL(s.find(TStringBuf("bar")), s.end());