```sql
CREATE TABLE test_tbl
(   `ip` String, `ipv6` IPv6 MATERIALIZED toIPv6(ip) )
ENGINE = Memory;

insert into test_tbl(ip) values ( 'fe80::9801:43ff:fe1f:7690'), ('1.1.1.1'), (''), ('::ffff:1.1.1.1' );

 DB::Exception: Invalid IPv6 value: while executing 'FUNCTION _CAST(toIPv6(ip) :: 2, 'IPv6' :: 1)


set cast_ipv4_ipv6_default_on_conversion_error=1;
insert into test_tbl(ip) values ( 'fe80::9801:43ff:fe1f:7690'), ('1.1.1.1'), (''), ('::ffff:1.1.1.1' );
 
 DB::Exception: Invalid IPv6 value: while executing 'FUNCTION _CAST(toIPv6(ip)
```

`toIPv6OrDefault` does not help in this case.

```sql
CREATE TABLE test_tbl
(   `ip` String, `ipv6` IPv6 MATERIALIZED toIPv6OrDefault(ip) )
ENGINE = Memory;

insert into test_tbl(ip) values ( 'fe80::9801:43ff:fe1f:7690'), ('1.1.1.1'), (''), ('::ffff:1.1.1.1' );
  DB::Exception: Invalid IPv6 value: while executing 'FUNCTION _CAST(toIPv6OrD

insert into test_tbl(ip) values ( 'fe80::9801:43ff:fe1f:7690'), ('1.1.1.1'), (''), ('::ffff:1.1.1.1' ), ('garbudge');
  DB::Exception: Invalid IPv6 value: while executing 'FUNCTION
```

WA:

```sql
CREATE TABLE test_tbl
(   `ip` String, `ipv6` IPv6 MATERIALIZED if(ip='', '::', ip) )
ENGINE = Memory;

insert into test_tbl(ip) values ( 'fe80::9801:43ff:fe1f:7690'), ('1.1.1.1'), (''), ('::ffff:1.1.1.1' );

select ip, ipv6 from test_tbl;
┌─ip────────────────────────┬─ipv6──────────────────────┐
│ fe80::9801:43ff:fe1f:7690 │ fe80::9801:43ff:fe1f:7690 │
│ 1.1.1.1                   │ ::ffff:1.1.1.1            │
│                           │ ::                        │
│ ::ffff:1.1.1.1            │ ::ffff:1.1.1.1            │
└───────────────────────────┴───────────────────────────┘
```
{
#ifdef OS_LINUX
    char buf[32] = {'\0'};
    snprintf(buf, sizeof(buf), "/proc/self/fd/%d", fd);
    char file_path[PATH_MAX] = {'\0'};
    if (readlink(buf, file_path, sizeof(file_path) - 1) != -1)
        return getFormatFromFileName(file_path, false);
    return "";
#elif defined(__APPLE__)
    char file_path[PATH_MAX] = {'\0'};
    if (fcntl(fd, F_GETPATH, file_path) != -1)
        return getFormatFromFileName(file_path, false);
    return "";
#else
    return "";
#endif
}
void FormatFactory::registerFileSegmentationEngine(const String & name, FileSegmentationEngine file_segmentation_engine)