dbms: fixed CAST String to Enum [#METR-19265].

dbms/include/DB/DataTypes/DataTypeEnum.h

@@ -137,14 +137,13 @@ public:
 		return it->second;
 	}
 
-	FieldType getValue(const std::string & name) const
+	FieldType getValue(StringRef name) const
 	{
-		const auto it = name_to_value_map.find(StringRef{name});
+		const auto it = name_to_value_map.find(name);
 		if (it == std::end(name_to_value_map))
 			throw Exception{
-				"Unknown element '" + name + "' for type " + getName(),
-				ErrorCodes::LOGICAL_ERROR
-			};
+				"Unknown element '" + name.toString() + "' for type " + getName(),
+				ErrorCodes::LOGICAL_ERROR};
 
 		return it->second;
 	}
@@ -175,7 +174,7 @@ public:
 	{
 		std::string name;
 		readString(name, istr);
-		field = nearestFieldType(getValue(name));
+		field = nearestFieldType(getValue(StringRef(name)));
 	}
 
 	void serializeTextEscaped(const Field & field, WriteBuffer & ostr) const override
@@ -187,7 +186,7 @@ public:
 	{
 		std::string name;
 		readEscapedString(name, istr);
-		field = nearestFieldType(getValue(name));
+		field = nearestFieldType(getValue(StringRef(name)));
 	}
 
 	void serializeTextQuoted(const Field & field, WriteBuffer & ostr) const override
@@ -199,7 +198,7 @@ public:
 	{
 		std::string name;
 		readQuotedString(name, istr);
-		field = nearestFieldType(getValue(name));
+		field = nearestFieldType(getValue(StringRef(name)));
 	}
 
 	void serializeTextJSON(const Field & field, WriteBuffer & ostr) const override

dbms/include/DB/Functions/FunctionsConversion.h

@@ -1744,7 +1744,8 @@ class FunctionCast final : public IFunction
 	template <typename ColumnStringType, typename EnumType>
 	auto createStringToEnumWrapper()
 	{
-		return [] (Block & block, const ColumnNumbers & arguments, const size_t result) {
+		return [] (Block & block, const ColumnNumbers & arguments, const size_t result)
+		{
 			const auto first_col = block.getByPosition(arguments.front()).column.get();
 
 			auto & col_with_type_and_name = block.getByPosition(result);
@@ -1755,12 +1756,12 @@ class FunctionCast final : public IFunction
 			{
 				const auto size = col->size();
 
-				const auto res = result_type.createColumn();
-				auto & out_data = static_cast<typename EnumType::ColumnType &>(*result_col).getData();
+				auto res = result_type.createColumn();
+				auto & out_data = static_cast<typename EnumType::ColumnType &>(*res).getData();
 				out_data.resize(size);
 
 				for (const auto i : ext::range(0, size))
-					out_data[i] = result_type.getValue(col->getDataAt(i).toString());
+					out_data[i] = result_type.getValue(col->getDataAt(i));
 
 				result_col = res;
 			}