dbms: fixed function visibleWidth for enums [#METR-19265].

dbms/include/DB/DataTypes/DataTypeEnum.h

@@ -125,13 +125,6 @@ public:
 
 	bool behavesAsNumber() const override { return true; }
 
-	/// Returns length of textual name for an enum element (used in FunctionVisibleWidth)
-	std::size_t getNameLength(const FieldType & value) const
-	{
-		/// @todo length of escaped string should be calculated here
-		return getNameForValue(value).size;
-	}
-
 	const StringRef & getNameForValue(const FieldType & value) const
 	{
 		const auto it = value_to_name_map.find(value);

dbms/include/DB/Functions/FunctionsConversion.h

@@ -347,7 +347,6 @@ template <typename FieldType> struct FormatImpl<DataTypeEnum<FieldType>>
 {
 	static void execute(const FieldType x, WriteBuffer & wb, const DataTypeEnum<FieldType> & type)
 	{
-		/// @todo should we escape the string here? Presumably no as it will be escaped twice otherwise
 		writeString(type.getNameForValue(x), wb);
 	}
 };
@@ -1724,23 +1723,6 @@ class FunctionCast final : public IFunction
 		using NameValuePair = std::pair<std::string, ValueType>;
 		using EnumValues = std::vector<NameValuePair>;
 
-//		EnumValues value_intersection;
-//		std::set_intersection(std::begin(from_values), std::end(from_values),
-//			std::begin(to_values), std::end(to_values), std::back_inserter(value_intersection),
-//			[] (auto && from, auto && to) { return from.second < to.second; });
-//
-//		for (const auto & name_value : value_intersection)
-//		{
-//			const auto & old_name = name_value.first;
-//			const auto & new_name = to_type->getNameForValue(name_value.second).toString();
-//			if (old_name != new_name)
-//				throw Exception{
-//					"Enum conversion changes name for value " + toString(name_value.second) +
-//						" from '" + old_name + "' to '" + new_name + "'",
-//					ErrorCodes::CANNOT_CONVERT_TYPE
-//				};
-//		}
-
 		EnumValues name_intersection;
 		std::set_intersection(std::begin(from_values), std::end(from_values),
 			std::begin(to_values), std::end(to_values), std::back_inserter(name_intersection),

dbms/src/Functions/FunctionsMiscellaneous.cpp

@@ -145,34 +145,24 @@ namespace VisibleWidth
 				const auto & in = col->getData();
 				auto & out = res->getData();
 
-				String str;
-				
 				for (const auto & idx_num : ext::enumerate(in))
 				{
-					/// escape name to calculate correct length
-					{
-						WriteBufferFromString out{str};
-						writeEscapedString(type->getNameForValue(idx_num.second), out);
-					}
-					
-					out[idx_num.first] = str.size();
+					StringRef name = type->getNameForValue(idx_num.second);
+					out[idx_num.first] = stringWidth(
+						reinterpret_cast<const UInt8 *>(name.data),
+						reinterpret_cast<const UInt8 *>(name.data) + name.size);
 				}
 
 				return true;
 			}
 			else if (const auto col = typeid_cast<const typename DataTypeEnum::ConstColumnType *>(column.get()))
 			{
-				String str;
-
-				/// escape name to calculate correct length
-				{
-					WriteBufferFromString out{str};
-					writeEscapedString(type->getNameForValue(col->getData()), out);
-				}
+				StringRef name = type->getNameForValue(col->getData());
 
 				block.getByPosition(result).column = new ColumnConstUInt64{
-					col->size(), str.size()
-				};
+					col->size(), stringWidth(
+						reinterpret_cast<const UInt8 *>(name.data),
+						reinterpret_cast<const UInt8 *>(name.data) + name.size)};
 
 				return true;
 			}