microsoftGH-5469

Author: StephanTLavavej

stl/inc/locale

@@ -186,8 +186,8 @@ protected:
 
     _NODISCARD virtual long __CLR_OR_THIS_CALL do_hash(const _Elem* _First, const _Elem* _Last) const {
         // compute hash code for [_First, _Last)
-        _Adl_verify_range(_First, _Last);
-        return static_cast<long>(_Hash_array_representation(_First, static_cast<size_t>(_Last - _First)));
+        const auto _Sortkey = collate::do_transform(_First, _Last);
+        return static_cast<long>(_Hash_array_representation(_Sortkey.data(), _Sortkey.size()));
     }
 
 private:

tests/std/tests/GH_005236_collate_facet/test.cpp

@@ -96,6 +96,24 @@ void test_gh_5210() {
 #endif // !defined(SKIP_COLLATE_TRANSFORM_TESTS)
 }
 
+void test_gh_5212_compare_hash(const collate<wchar_t>& coll, const wstring& string1, const wstring& string2) {
+    assert(coll.hash(string1.data(), string1.data() + string1.size())
+           == coll.hash(string2.data(), string2.data() + string2.size()));
+}
+
+// GH-5212: std::collate_byname<_Elem>::hash() yields different hashes for strings that collate the same
+void test_gh_5212() {
+    const locale loc("de-DE_phoneb");
+    const auto& coll = use_facet<collate<wchar_t>>(loc);
+
+    // sharp s collates like "ss"
+    test_gh_5212_compare_hash(coll, L"Strasse", L"Stra\u00DFe"); // U+00DF LATIN SMALL LETTER SHARP S
+    // umlaut a collates like "ae"
+    test_gh_5212_compare_hash(coll, L"Kaetzchen", L"K\u00E4tzchen"); // U+00E4 LATIN SMALL LETTER A WITH DIAERESIS
+    // umlaut A collates like "AE"
+    test_gh_5212_compare_hash(coll, L"AErmel", L"\u00C4rmel"); // U+00C4 LATIN CAPITAL LETTER A WITH DIAERESIS
+}
+
 // GH-5236 "std::collate<wchar_t> does not respect collation order when compiled with /MD(d) /Zc:wchar_t-"
 void test_gh_5236() {
     const wchar_t Ue = L'\u00DC'; // U+00DC LATIN CAPITAL LETTER U WITH DIARESIS
@@ -117,5 +135,6 @@ void test_gh_5236() {
 
 int main() {
     test_gh_5210();
+    test_gh_5212();
     test_gh_5236();
 }