Remove std::nullptr_t ctor for TString

commit_hash:6b02e6cb83bde366477f7d53b6cd6c00bffdb4d6

Author: dgolear

util/generic/strbuf.h

@@ -98,6 +98,8 @@ class TBasicStringBuf: public std::basic_string_view<TCharType>,
      *  to generate compilation error instead.
      */
     constexpr inline TBasicStringBuf(std::nullptr_t begin, size_t size) = delete;
+    // TODO: Uncomment.
+    // constexpr TBasicStringBuf(std::nullptr_t) = delete;
 
     constexpr inline TBasicStringBuf(const TCharType* data Y_LIFETIME_BOUND, size_t size) noexcept
         : TStringView(data, size)

util/generic/string.h

@@ -463,8 +463,7 @@ class TBasicString: public TStringBase<TBasicString<TCharType, TTraits>, TCharTy
         : TBasicString(pc, TBase::StrLen(pc))
     {
     }
-    // TODO thegeorg@: uncomment and fix clients
-    // TBasicString(std::nullptr_t) = delete;
+    TBasicString(std::nullptr_t) = delete;
 
     TBasicString(const TCharType* pc, size_t n)
 #ifdef TSTRING_IS_STD_STRING

util/generic/string_ut.h

@@ -525,18 +525,14 @@ class TStringTestImpl {
     }
 
     void TestConstructors() {
-        TStringType s0(nullptr);
+        TStringType s0;
         UNIT_ASSERT(s0.size() == 0);
-        UNIT_ASSERT_EQUAL(s0, TStringType());
 
         TStringType s;
         TStringType s1(*Data._0());
         TStringType s2(Data._0());
         UNIT_ASSERT(s1 == s2);
 
-        TStringType fromZero(0);
-        UNIT_ASSERT_VALUES_EQUAL(fromZero.size(), 0u);
-
         TStringType fromChar(char_type('a'));
         UNIT_ASSERT_VALUES_EQUAL(fromChar.size(), 1u);
         UNIT_ASSERT_VALUES_EQUAL(fromChar[0], char_type('a'));