Pool construction depends on the install request now, so only required
packages get loaded, add some structure for future asynchronously
loading composer repositories
It is known that composer update takes a lot of memory: #5915, #5902,
I am playing with a profiler (@blackfireio) to make a demo in my local
PHP meetup (@phpvigo) and I found out a way to use less memory. These
are my first tests:
* Private project using PHP 5.6:
* Memory: from 1.31GB to 1.07GB
* Wall Time: from 2min 8s to 1min 33s
* symfony-demo using PHP 7.1 in my old mac book:
* Memory: from 667MB to 523MB
* Wall Time: from 5min 29s to 5min 28s
Not use an array inside conflict rules is this improvement main idea:
```php
<?php
//Memory 38MB
gc_collect_cycles();
gc_disable();
class Rule
{
public $literals;
public function __construct(array $literals)
{
$this->literals = $literals;
}
}
$rules = array();
$i = 0;
while ($i<80000){ //
$i++;
$array = array(-$i, $i);
$rule = new Rule($array);
$rules[] = $rule;
}
```
```php
<?php
//Memory 11.1MB
gc_collect_cycles();
gc_disable();
class Rule2Literals
{
public $literal1;
public $literal2;
public function __construct($literal1, $literal2)
{
$this->literal1 = $literal1;
$this->literal2 = $literal2;
}
}
$rules = array();
$i = 0;
while ($i<80000){ //
$i++;
$rule = new ConflictRule(-$i, $i);
$rules[] = $rule;
}
```
More info https://github.com/composer/composer/pull/6168
Since we no longer have suggest/recommend rules and no longer use any update
or feature rules so packages are removed by default, we do not need weak rules
anymore.
Jordi Boggiano