Broken assert for array and list - DocblockTypeContradiction

[kkmuffme]

https://psalm.dev/r/ea9ecf75b9

As we see in line 20, psalm correctly infers that $foo can be type list when checking with array_values

When using a custom assert function, it correctly asserts it, but reports a false positive DocblockTypeContradiction on the if condition in line 23

What actually happens here is, that it assumes that @psalm-assert type array<string, string> does not contain list<string> which is correct - however why does it report this as a DocblockTypeContradiction in the place where the function is called?

How can I assert if true => list<string>, if false => array<string, string>?

[psalm-github-bot]

I found these snippets:

https://psalm.dev/r/ea9ecf75b9

<?php

/**
 *
 * @param array<string, string>|list<string> $arg
 * @return bool
 *
 * @psalm-assert array<string, string> $arg
 * @psalm-assert-if-true =list<string> $arg
 */
function is_array_or_list( $arg ) {}

/**
 * @var array<string, string>|list<string> $foo
 */
$bar = $foo;
/** @psalm-trace $bar */;

if ( $foo === array_values( $foo ) ) {
   /** @psalm-trace $foo */;
}

if ( is_array_or_list( $foo ) === true ) {
    /** @psalm-trace $foo */;
} else {
    /** @psalm-trace $foo */;
}

Psalm output (using commit ef1264b):

ERROR: InvalidReturnType - 6:12 - No return statements were found for method is_array_or_list but return type 'bool' was expected

INFO: Trace - 17:25 - $bar: array<int<0, max>|string, string>

INFO: Trace - 20:28 - $foo: list<string>

ERROR: DocblockTypeContradiction - 23:6 - Cannot resolve types for $foo - docblock-defined type array<string, string> does not contain list<string>

INFO: Trace - 24:29 - $foo: list<string>

INFO: Trace - 26:29 - $foo: array<string, string>

[orklah]

Current situation seems correct @psalm-assert means that if the function doesn't throw, you have the type array<string, string> but you also say that if the function returns true, you have a list<string>. Those two are contradiction and assertions are considered docblocks so there's a fail.

In theory, this should work: https://psalm.dev/r/06c99cf8ac but it doesn't

[psalm-github-bot]

I found these snippets:

https://psalm.dev/r/06c99cf8ac

<?php

/**
 *
 * @param array<string, string>|list<string> $arg
 * @return bool
 *
 * @psalm-assert-if-false =array<string, string> $arg
 * @psalm-assert-if-true =list<string> $arg
 */
function is_array_or_list( $arg ) {}

/**
 * @var array<string, string>|list<string> $foo
 */
$bar = $foo;
/** @psalm-trace $bar */;

if ( $foo === array_values( $foo ) ) {
   /** @psalm-trace $foo */;
}

if ( is_array_or_list( $foo ) === true ) {
    /** @psalm-trace $foo */;
} else {
    /** @psalm-trace $foo */;
}

Psalm output (using commit e81823e):

ERROR: InvalidReturnType - 6:12 - No return statements were found for method is_array_or_list but return type 'bool' was expected

INFO: Trace - 17:25 - $bar: array<int<0, max>|string, string>

INFO: Trace - 20:28 - $foo: list<string>

INFO: Trace - 24:29 - $foo: array<int<0, max>|string, string>

INFO: Trace - 26:29 - $foo: array<int<0, max>|string, string>

[kkmuffme]

Current situation seems correct @psalm-assert means that if the function doesn't throw, you have the type array<string, string>

Which is fine, the issue is that it should report this for the assertion, not at every place this function is called?

Afaik this was working fine in v4, this is a new issue in v5

In theory, this should work: https://psalm.dev/r/06c99cf8ac but it doesn't

Yes @psalm-assert-if-false and @psalm-assert-if-true should work when used together.

[psalm-github-bot]

I found these snippets:

https://psalm.dev/r/06c99cf8ac

<?php

/**
 *
 * @param array<string, string>|list<string> $arg
 * @return bool
 *
 * @psalm-assert-if-false =array<string, string> $arg
 * @psalm-assert-if-true =list<string> $arg
 */
function is_array_or_list( $arg ) {}

/**
 * @var array<string, string>|list<string> $foo
 */
$bar = $foo;
/** @psalm-trace $bar */;

if ( $foo === array_values( $foo ) ) {
   /** @psalm-trace $foo */;
}

if ( is_array_or_list( $foo ) === true ) {
    /** @psalm-trace $foo */;
} else {
    /** @psalm-trace $foo */;
}

Psalm output (using commit e81823e):

ERROR: InvalidReturnType - 6:12 - No return statements were found for method is_array_or_list but return type 'bool' was expected

INFO: Trace - 17:25 - $bar: array<int<0, max>|string, string>

INFO: Trace - 20:28 - $foo: list<string>

INFO: Trace - 24:29 - $foo: array<int<0, max>|string, string>

INFO: Trace - 26:29 - $foo: array<int<0, max>|string, string>

[orklah]

As far as I know, contradiction in assertions were always reported where the contradiction is processed, on the method call.

[kkmuffme]

I didn't have this issue in v4 though (this same code passed in v4 without any errors, as I am just revisiting a file that was last modified in September and passed without errors back then)

[kkmuffme]

Works fine for any types e.g. int|list https://psalm.dev/r/4733a4c121 except for array|list since they are combined into 1 type - which is where the use of @psalm-assert-if-false combined with @psalm-assert-if-true would come in handy

[psalm-github-bot]

I found these snippets:

https://psalm.dev/r/4733a4c121

<?php

/**
 *
 * @param int|list<string> $arg
 * @return bool
 *
 * @psalm-assert-if-true list<string> $arg
 */
function is_array_or_int( $arg ) {}

/**
 * @var int|list<string> $foo
 */
$bar = $foo;

if ( is_array_or_int( $foo ) ) {
   /** @psalm-trace $foo */;
} else {
    /** @psalm-trace $foo */;
}

Psalm output (using commit 7d6a48a):

ERROR: InvalidReturnType - 6:12 - No return statements were found for method is_array_or_int but return type 'bool' was expected

INFO: Trace - 18:28 - $foo: list<string>

INFO: Trace - 20:29 - $foo: int