Fix possible Logical error on bad Nullable parsing for text formats

src/DataTypes/Serializations/SerializationNullable.cpp

@@ -355,6 +355,9 @@ ReturnType SerializationNullable::deserializeTextEscapedAndRawImpl(IColumn & col
         /// It can happen only if there is a string instead of a number
         /// or if someone uses tab or LF in TSV null_representation.
         /// In the first case we cannot continue reading anyway. The second case seems to be unlikely.
+        /// We also should delete incorrectly deserialized value from nested column.
+        nested_column.popBack(1);
+
         if (null_representation.find('\t') != std::string::npos || null_representation.find('\n') != std::string::npos)
             throw DB::ParsingException(ErrorCodes::CANNOT_READ_ALL_DATA, "TSV custom null representation "
                                        "containing '\\t' or '\\n' may not work correctly for large input.");
@@ -447,6 +450,8 @@ ReturnType SerializationNullable::deserializeTextQuotedImpl(IColumn & column, Re
 
         /// We have some unread data in PeekableReadBuffer own memory.
         /// It can happen only if there is an unquoted string instead of a number.
+        /// We also should delete incorrectly deserialized value from nested column.
+        nested_column.popBack(1);
         throw DB::ParsingException(
             ErrorCodes::CANNOT_READ_ALL_DATA,
             "Error while parsing Nullable: got an unquoted string {} instead of a number",
@@ -579,6 +584,9 @@ ReturnType SerializationNullable::deserializeTextCSVImpl(IColumn & column, ReadB
         /// It can happen only if there is an unquoted string instead of a number
         /// or if someone uses csv delimiter, LF or CR in CSV null representation.
         /// In the first case we cannot continue reading anyway. The second case seems to be unlikely.
+        /// We also should delete incorrectly deserialized value from nested column.
+        nested_column.popBack(1);
+
         if (null_representation.find(settings.csv.delimiter) != std::string::npos || null_representation.find('\r') != std::string::npos
             || null_representation.find('\n') != std::string::npos)
             throw DB::ParsingException(ErrorCodes::CANNOT_READ_ALL_DATA, "CSV custom null representation containing "

tests/queries/0_stateless/02751_text_formats_bad_nullable_parsing.reference

@@ -0,0 +1,3 @@
+1	\N
+1	\N
+1	\N

tests/queries/0_stateless/02751_text_formats_bad_nullable_parsing.sh

@@ -0,0 +1,15 @@
+#!/usr/bin/env bash
+
+# NOTE: this sh wrapper is required because of shell_config
+
+CURDIR=$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)
+# shellcheck source=../shell_config.sh
+. "$CURDIR"/../shell_config.sh
+
+$CLICKHOUSE_CLIENT -q "drop table if exists test" 
+$CLICKHOUSE_CLIENT -q "create table test (x UInt32, y Nullable(UInt32)) engine=MergeTree order by x"
+$CLICKHOUSE_CLIENT -q "select '1\t\\\N\n2\t\\\' format RawBLOB" | $CLICKHOUSE_CLIENT -q "insert into test settings input_format_allow_errors_num=1 format TSV"
+$CLICKHOUSE_CLIENT -q "select '1,\\\N\n2,\\\' format RawBLOB" | $CLICKHOUSE_CLIENT -q "insert into test settings input_format_allow_errors_num=1 format CSV"
+$CLICKHOUSE_CLIENT -q "select '1\tNULL\n2\tN' format RawBLOB" | $CLICKHOUSE_CLIENT -q "insert into test settings input_format_allow_errors_num=2, format_custom_escaping_rule='Quoted' format CustomSeparated"
+$CLICKHOUSE_CLIENT -q "select * from test"
+$CLICKHOUSE_CLIENT -q "drop table test";