Float values are being stored as negative

[xPaw]

I upgraded from PHP 7.4 to 8.1 and noticed this issue where floats are being stored as negative now. I didn't upgrade memcached server. Unsure if it worked on PHP 8.0.

Previous version: php7.4-memcached 3.1.5+2.2.0-14+0~20220117.37+debian10~1.gbpc8d81e
Version: php8.1-memcached 3.1.5+2.2.0-14+0~20220117.37+debian11~1.gbpc8d81e
(deb.sury.org package)

$Memcached = new Memcached();
$Memcached->addServer( '/run/memcached/memcached.sock', 0 );
$Memcached->setOption(Memcached::OPT_SERIALIZER, Memcached::SERIALIZER_PHP);

var_dump($Memcached->set( 'testkey', 1337.123, 60 ));
var_dump($Memcached->get( 'testkey'));

var_dump($Memcached->set( 'testkey2', -400.100, 60 ));
var_dump($Memcached->get( 'testkey2'));

var_dump($Memcached->set( 'testkey3', 600, 60 ));
var_dump($Memcached->get( 'testkey3'));

var_dump($Memcached->set( 'testkey4', ['test' => 500.60], 60 ));
var_dump($Memcached->get( 'testkey4'));

Output:

bool(true)
float(-1337.123)
bool(true)
float(-400.1)
bool(true)
int(600)
bool(true)
array(1) {
  ["test"]=>
  float(500.6)
}

Seems like this problem is only observed for bare float values, and not when they're in an array.

Verified that it is being stored like this:

$ memccat --servers=/run/memcached/memcached.sock testkey
-1337.123

$ memccat --servers=/run/memcached/memcached.sock testkey4
a:1:{s:4:"test";d:500.6;}

I initially assumed it was an igbinary issue but changing to SERIALIZER_PHP still observes this issue.

strace confirms this:

socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0) = 4
connect(4, {sa_family=AF_UNIX, sun_path="/run/memcached/memcached.sock"}, 110) = 0
sendto(4, "set testkey 2 60 9\r\n-1337.123\r\n", 31, MSG_NOSIGNAL, NULL, 0) = 31
recvfrom(4, "STORED\r\n", 8196, MSG_NOSIGNAL, NULL, NULL) = 8

[remicollet]

Please try 3.2.0RC1

[SerafimArts]

Reproduced the same problem.

3.2.0 (release build) exactly fixes this issue.

P.S. I think the issue can be closed. Thank you!