```sql
drop table if exists src;

create table src( A Int64, B String, C String) Engine=MergeTree order by A
SETTINGS min_bytes_for_wide_part=0;
insert into src values(1, 'one', 'test');

alter table src detach partition tuple();

alter table src modify column B Nullable(String);

alter table src attach partition tuple();
select * from src;
┌─A─┬─B───┬─C────┐
│ 1 │ one │ test │
└───┴─────┴──────┘

alter table src update C = 'test1' where 1 settings mutations_sync=2;

select * from src;
┌─A─┬─B────┬─C─────┐
│ 1 │ ᴺᵁᴸᴸ │ test1 │   -- expected B='one'
└───┴──────┴───────┘
```

```sql
drop table if exists src;
create table src( A String, B String, C String) Engine=MergeTree order by A
SETTINGS min_bytes_for_wide_part=0;
insert into src values('one', 'one', 'test');

alter table src detach partition tuple();

alter table src modify column A LowCardinality(String);

alter table src attach partition tuple();

select * from src;
┌─A───┬─B───┬─C────┐
│ one │ one │ test │
└─────┴─────┴──────┘

alter table src update C = 'test1' where 1 settings mutations_sync=2;

select * from src;

Received exception from server (version 22.9.1):
Code: 49. DB::Exception: Received from localhost:9000. DB::Exception: 
Got empty stream for SerializationLowCardinality keys.: (while reading column A): 
(while reading from part /var/lib/clickhouse/store/11b/11b74812-48b9-4c1f-9bdc-3e7a28137a9e/all_3_3_0_4/ from mark 0 with max_rows_to_read = 1): 
While executing MergeTreeInOrder. (LOGICAL_ERROR)

```

```sql
drop table if exists src;
create table src( A String, B String, C String) Engine=MergeTree order by A
SETTINGS min_bytes_for_wide_part=0;
insert into src values('one', 'one', 'test');

alter table src detach partition tuple();

alter table src modify column A LowCardinality(String);

alter table src attach partition tuple();

select * from src;
┌─A───┬─B───┬─C────┐
│ one │ one │ test │
└─────┴─────┴──────┘

alter table src modify column C LowCardinality(String);

select * from src;

Received exception from server (version 22.9.3):
Code: 49. DB::Exception: Received from localhost:9000. 
DB::Exception: Got empty stream for SerializationLowCardinality keys.: 
```

related https://github.com/ClickHouse/ClickHouse/issues/42083 , https://github.com/ClickHouse/ClickHouse/issues/42074
(basically it's the same one issue, but I opened this one, because I think the root issue is in `alter update`.

it seems `alter update` updates columns.txt for all columns even if they are not participated in the `alter update`.
{
    Block cur_block;
    if (MutationHelpers::checkOperationIsNotCanceled(*ctx->merges_blocker, ctx->mutate_entry) && ctx->mutating_executor->pull(cur_block))
    {
        if (ctx->minmax_idx)
            ctx->minmax_idx->update(cur_block, ctx->data->getMinMaxColumnsNames(ctx->metadata_snapshot->getPartitionKey()));
        ctx->out->write(cur_block);
        for (size_t i = 0, size = ctx->projections_to_build.size(); i < size; ++i)
        {
            const auto & projection = *ctx->projections_to_build[i];
            auto projection_block = projection_squashes[i].add(projection.calculate(cur_block, ctx->context));
            if (projection_block)
            {
                auto tmp_part = MergeTreeDataWriter::writeTempProjectionPart(
                    *ctx->data, ctx->log, projection_block, projection, ctx->data_part_storage_builder, ctx->new_data_part.get(), ++block_num);
                tmp_part.builder->commit();
                tmp_part.finalize();
                projection_parts[projection.name].emplace_back(std::move(tmp_part.part));