https://clickhouse-test-reports.s3.yandex.net/13925/0f492917338ba5b20728563e38abc35be67d606c/stress_test_(memory)/stderr.log

MemorySanitizer: use-of-uninitialized-value in DB::FunctionToStringCutToZero::tryExecuteString.
Uninitialized value was created ... in DB::FunctionBase64ConversionDB::Base64Decode::executeImpl
(from ExecuteScalarSubqueriesVisitor -> ... -> InterpreterSelectQuery::getSampleBlockImpl() -> ... -> IFunction::executeImplDryRun())

There's only one query with `toStringCutToZero(base64Decode)` in server log

```
SELECT JSONExtractKeysAndValues(-0, (CAST((( SELECT ['"O'], (CAST((( SELECT toStringCutToZero((CAST((base64Decode('UE')) AS String))) ) AS op, ( SELECT positionCaseInsensitiveUTF8() ) AS uxxgbn) AS String)), (CAST((-44955.4) AS Date)), regionToDistrict(NULL) ) AS q) AS DateTime)))
```
{
        return ((string_length - string_count) / 3 + string_count) * 4 + string_count;
    }
};
struct Base64Decode
{
    static constexpr auto name = "base64Decode";
    static size_t getBufferSize(size_t string_length, size_t string_count)
    {
        return ((string_length - string_count) / 4 + string_count) * 3 + string_count;
    }
};
struct TryBase64Decode
{
    static constexpr auto name = "tryBase64Decode";
    static size_t getBufferSize(size_t string_length, size_t string_count)
    {
        return Base64Decode::getBufferSize(string_length, string_count);
    }
};
template <typename Func>
class FunctionBase64Conversion : public IFunction
{
public:
    static constexpr auto name = Func::name;
    static FunctionPtr create(const Context &)