Add stub for DatePeriod

[fluffycondor]

Fixes #5954

Actually I'd like to mark the returned Iterator as a non-empty one, it always yields at least one value (and 50 and 63 lines in the test actually should be non-nullable).
But I don't know how to do that :)

[AndrolGenhald]

Actually I'd like to mark the returned Iterator as a non-empty one, it always yields at least one value (and 50 and 63 lines in the test actually should be non-nullable).

I don't think that's possible unfortunately, and the only way I can think of to do it would be to add a template, which would make all other iterators more annoying to deal with.

[AndrolGenhald]

Per this comment it looks like we might need to have it implement Traversable instead and add the IteratorAggregate part in Php80.phpstub. It would be good to add a test for PHP 7.4 and 8.0 for that as well.

[fluffycondor]

it looks like we might need to have it implement Traversable instead and add the IteratorAggregate part in Php80.phpstub

Unfortunately, looks like I can't use a conditional @implements :(
It doesn't work whatever I try:
https://psalm.dev/r/f606edbe51
https://psalm.dev/r/46f7c9b9b4

[psalm-github-bot]

I found these snippets:

https://psalm.dev/r/f606edbe51

<?php
/**
 * @psalm-immutable
 *
 * @template-covariant Start of string|DateTimeInterface
 * @implements (Start is string ? Traversable<int, DateTime> : Traversable<int, Start>)
 */
class DatePeriod implements Traversable
{
    const EXCLUDE_START_DATE = 1;
    /**
     * @param Start $start
     * @param (Start is string ? 0|self::EXCLUDE_START_DATE : DateInterval) $interval
     * @param (Start is string ? never : DateTimeInterface|positive-int) $end
     * @param (Start is string ? never : 0|self::EXCLUDE_START_DATE) $options
     */
    public function __construct($start, $interval = 0, $end = 1, $options = 0) {}
}

Psalm output (using commit 4b2935f):

ERROR: InvalidDocblock - 8:1 - @template-implements has invalid class (Start is string ? Traversable<int, DateTime> : Traversable<int, Start:DatePeriod as DateTimeInterface|string>)

ERROR: MissingTemplateParam - 8:29 - DatePeriod has missing template params when extending Traversable, expecting 2

ERROR: InvalidTraversableImplementation - 8:7 - Traversable should be implemented by implementing IteratorAggregate or Iterator

https://psalm.dev/r/46f7c9b9b4

<?php
/**
 * @psalm-immutable
 *
 * @template-covariant Start of string|DateTimeInterface
 * @implements Traversable<int, (Start is string ? DateTime : Start)>
 */
class DatePeriod implements Traversable
{
    const EXCLUDE_START_DATE = 1;
    /**
     * @param Start $start
     * @param (Start is string ? 0|self::EXCLUDE_START_DATE : DateInterval) $interval
     * @param (Start is string ? never : DateTimeInterface|positive-int) $end
     * @param (Start is string ? never : 0|self::EXCLUDE_START_DATE) $options
     */
    public function __construct($start, $interval = 0, $end = 1, $options = 0) {}
}

$period = new DatePeriod("R4/2012-07-01T00:00:00Z/P7D");
foreach ($period as $dt) {
    echo $dt->format("Y-m-d");
}

Psalm output (using commit 4b2935f):

ERROR: InvalidMethodCall - 22:15 - Cannot call method on (Start is string ? DateTime : Start:DatePeriod as DateTimeInterface|string) variable $dt

INFO: MixedArgument - 22:10 - Argument 1 of echo cannot be mixed, expecting string

ERROR: InvalidTraversableImplementation - 8:7 - Traversable should be implemented by implementing IteratorAggregate or Iterator

[AndrolGenhald]

@fluffycondor It looks like you must have branched from your fork's 4.x branch, which is quite a bit behind. Could you rebase on the current 4.x? I think that should fix the test-with-real-projects PHPUnit test.

[AndrolGenhald]

Thanks!