[pdo_firebird] float, double value is incorrect #13119

Description

The following code:

<?php

$db = new PDO(/* firebird */);

$db->exec('CREATE TABLE test (f_val FLOAT, d_val DOUBLE PRECISION)');
$db->exec('INSERT INTO test VALUES (0.0000001, 0.00000001)');
$stmt = $db->query('select * from test');
var_dump($stmt->fetchAll(PDO::FETCH_ASSOC));

Resulted in this output:

array(1) {
  [0]=>
  array(2) {
    ["F_VAL"]=>
    string(8) "0.000000"
    ["D_VAL"]=>
    string(8) "0.000000"
  }
}

But I expected this output instead:

array(1) {
  [0]=>
  array(2) {
    ["F_VAL"]=>
    string(8) "0.0000001"
    ["D_VAL"]=>
    string(8) "0.00000001"
  }
}

After trying various things, it seems that the fraction part is displayed as a fixed 6 digits. e.g. 12.000000001 => 12.000000
It's late today, so I'll try again tomorrow.

(In the first place, I think I want the value to be a native type, but I won't consider that for now.)

PHP Version

= PHP8.2

Operating System

Ubuntu20.04(docker)