Execution time increases exponentially when merging arrays #4308
Description
Bug report
Analysis time increases exponentially with the number of optional array keys.
| Number of optional array items | Execution Time |
|---|---|
| < 6 | 0.5s |
| 6 | 1.06s |
| 7 | 2.35s |
| 8 | 9.38s |
| 9 | 41.57s |
Code snippet that reproduces the problem
<?php
class Test
{
/**
* @var (string|int|null)[]
* @phpstan-var array{
* prop1?: string, prop2?: string, prop3?: string,
* prop4?: string, prop5?: string, prop6?: string,
* prop7?: string, prop8?: int, prop9?: int
* }
*/
protected array $updateData = [];
/**
* @phpstan-param array{
* prop1?: string, prop2?: string, prop3?: string,
* prop4?: string, prop5?: string, prop6?: string,
* prop7?: string, prop8?: int, prop9?: int
* } $data
*/
public function update(array $data): void
{
$this->updateData = $data + $this->updateData;
}
}
I was unable to reproduce the issue with PHPStan.org, since the analysis was timing out when there were more than 7 optional keys.
Expected output
Execution time to increase linearly.