```
$ ~/arc/build/clickhouse/programs/clickhouse client
ClickHouse client version 21.2.1.1-arcadia.
Connecting to localhost:9000 as user default.
Connected to ClickHouse server version 21.2.1 revision 54447.

max42-dev.sas.yp-c.yandex.net :) create table t(a Tuple(UInt8, UInt8)) engine = Log()

CREATE TABLE t
(
    `a` Tuple(UInt8, UInt8)
)
ENGINE = Log

Query id: b49dbb5d-d2a9-4c99-b90e-00c60edf2103

Ok.

0 rows in set. Elapsed: 0.005 sec. 

max42-dev.sas.yp-c.yandex.net :) insert into t values ((NULL, 42))

INSERT INTO t VALUES

Query id: 318d6f3e-f3bc-467c-85ff-62da908230dd

Logical error: 'Unexpected literal type inside Array: Nothing. It's a bug'.
Aborted (core dumped)
```

This is CH similar to one from Arcadia r7788360 (~fresh master version from GH).

(you don't have to strictly follow this form)

Chunk generate() override;
    void readRow(MutableColumns & columns, size_t row_num);
    bool tryParseExpressionUsingTemplate(MutableColumnPtr & column, size_t column_idx);
    ALWAYS_INLINE inline bool tryReadValue(IColumn & column, size_t column_idx);
    bool parseExpression(IColumn & column, size_t column_idx);
    ALWAYS_INLINE inline void assertDelimiterAfterValue(size_t column_idx);
    ALWAYS_INLINE inline bool checkDelimiterAfterValue(size_t column_idx);
    bool shouldDeduceNewTemplate(size_t column_idx);
    void readPrefix();
    void readSuffix();
    bool skipToNextRow(size_t min_chunk_bytes = 0, int balance = 0);
private:
    PeekableReadBuffer buf;
    const RowInputFormatParams params;
    std::unique_ptr<Context> context;   
    const FormatSettings format_settings;
    const size_t num_columns;
    size_t total_rows = 0;
    std::vector<ParserType> parser_type_for_column;
    std::vector<size_t> attempts_to_deduce_template;
    std::vector<size_t> attempts_to_deduce_template_cached;
    std::vector<size_t> rows_parsed_using_template;
    ParserExpression parser;
    ConstantExpressionTemplates templates;
    ConstantExpressionTemplate::Cache templates_cache;
    const DataTypes types;
    BlockMissingValues block_missing_values;
};
}