False positive TooFewArguments with non-empty-list and spread operator
#7603
Comments
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I found these snippets: https://psalm.dev/r/09a02c2b5f<?php
function func(string $item1, string $item2, string ...$otherItems): array {
return [$item1, $item2, ...$otherItems];
}
/**
* @var non-empty-list<string> $existingItems
* @var string $newItem
*/
func(...[...$existingItems, $newItem]);https://psalm.dev/r/5f60f9ef1b<?php
function func(string $item1, string $item2, string ...$otherItems): array {
return [$item1, $item2, ...$otherItems];
}
$existingItems = ['item1'];
$newItem = 'item2';
func(...[...$existingItems, $newItem]); |
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Psalm doesn't have a concept of 'list with at least N elements, N > 1'. So inner splat results in |
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I found these snippets: https://psalm.dev/r/3cdda0aa21<?php
function func(string $item1, string $item2, string ...$otherItems): array {
return [$item1, $item2, ...$otherItems];
}
/**
* @var non-empty-list<string> $existingItems
* @var string $newItem
*/
$args = [...$existingItems, $newItem];
/** @psalm-trace $args */;
func(...$args); |
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Basically, we can't do much here given the confines of the type system we currently have in Psalm. |
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This could become an improvement though. There are already places in Psalm's code where we check for min_count (for example, TypeCombiner). The goal is to check a combined array is never empty. It could make sense to store min_count on non-empty-arrays / list for this. We already have assertions for that and everything... |
Thanks, I see that now. Before 4.19 there was no error reported, so I thought psalm was able to track the min size of the list. |
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I found these snippets: https://psalm.dev/r/3cdda0aa21<?php
function func(string $item1, string $item2, string ...$otherItems): array {
return [$item1, $item2, ...$otherItems];
}
/**
* @var non-empty-list<string> $existingItems
* @var string $newItem
*/
$args = [...$existingItems, $newItem];
/** @psalm-trace $args */;
func(...$args); |
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I completely reworked this check here: #7348 It was unable to check for named arguments and it forced me to start from scratch. I may have missed some checks Psalm was making in order to reduce the amount of false positives though. For example, I could add something in here that prevent emitting this issue when we have a non-empty-array with no known count. This would probably reduce false positives (as well as removing some possible bug warning for unckecked arrays...). What do you think @dsech @weirdan ? Maybe we should only do that when we have a variadic argument on the end? (For all other cases, I think we can expect a count() === X to be made before the call...) |
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Ideally I'd love to see psalm keep track of min and max size of the array/list (obviously). Personally I'm good with just leaving a |
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We can express the unbounded list with N guaranteed elements in Psalm 5 as |
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I found these snippets: https://psalm.dev/r/80dd0babf0<?php
function func(string $item1, string $item2, string ...$otherItems): array {
return [$item1, $item2, ...$otherItems];
}
/**
* @var non-empty-list<string> $existingItems
* @var string $newItem
*/
$z = [...$existingItems, $newItem];
assert(count($z) >= 2);
/** @psalm-trace $z */;
func(...$z); |
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It looks like this is fixed, because the But (not sure if relevant to this issue) the size >= 2 information is lost after calling |
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I found these snippets: https://psalm.dev/r/80dd0babf0<?php
function func(string $item1, string $item2, string ...$otherItems): array {
return [$item1, $item2, ...$otherItems];
}
/**
* @var non-empty-list<string> $existingItems
* @var string $newItem
*/
$z = [...$existingItems, $newItem];
assert(count($z) >= 2);
/** @psalm-trace $z */;
func(...$z);https://psalm.dev/r/18a8f67489<?php
function func(string $item1, string $item2, string ...$otherItems): array {
return [$item1, $item2, ...$otherItems];
}
/**
* @var non-empty-list<string> $existingItems
* @var string $newItem
*/
$z = [...$existingItems, $newItem];
/** @psalm-trace $z */;
func(...$z);
/** @psalm-trace $z */https://psalm.dev/r/90e8d5a001<?php
function func(string $item1, string $item2, string ...$otherItems): array {
return [$item1, $item2, ...$otherItems];
}
/**
* @var non-empty-list<string> $existingItems
* @var string $newItem
*/
$z = [...$existingItems, $newItem];
/** @psalm-trace $z */
func(...$z); |
https://psalm.dev/r/09a02c2b5f
The issue exists in versions >=4.19.0
Looks to be related to the
non-empty-listtypehint, because there is no error reported if the variables are declared: https://psalm.dev/r/5f60f9ef1bThe text was updated successfully, but these errors were encountered: