Argument 4 of mkdir cannot be null

[steal3rd]

Psalm is reporting the fourth argument of the mkdir() function cannot be null, but the function works as expected if used anyway.

The full message is:

Argument 4 of mkdir cannot be null, null value provided to parameter with type resource

And can be see with this example:

https://psalm.dev/r/6c64902528

mkdir("home/sample", 0755, true); // Works
mkdir("home/sample", 0755, true, null); // Also works

It's difficult to find examples of how this parameter would be used, but PHP does support passing a null for this argument. The docs describe it that way as well.

https://www.php.net/manual/en/function.mkdir

mkdir(
	string $directory,
	int $permissions = 0777,
	bool $recursive = false,
	?resource $context = null
): bool

[psalm-github-bot]

I found these snippets:

https://psalm.dev/r/6c64902528

<?php

mkdir("home/sample", 0755, true, null)

Psalm output (using commit 3600d51):

ERROR: ParseError - 3:39 - Syntax error, unexpected EOF on line 3

ERROR: NullArgument - 3:34 - Argument 4 of mkdir cannot be null, null value provided to parameter with type resource

[ging-dev]

Psalm is reporting the fourth argument of the mkdir() function cannot be null, but the function works as expected if used anyway.

The full message is:

Argument 4 of mkdir cannot be null, null value provided to parameter with type resource

And can be see with this example:

https://psalm.dev/r/6c64902528

mkdir("home/sample", 0755, true); // Works
mkdir("home/sample", 0755, true, null); // Also works

It's difficult to find examples of how this parameter would be used, but PHP does support passing a null for this argument. The docs describe it that way as well.

https://www.php.net/manual/en/function.mkdir

mkdir(
	string $directory,
	int $permissions = 0777,
	bool $recursive = false,
	?resource $context = null
): bool

You can fix callmap signature in this line: https://github.com/vimeo/psalm/blob/dca888c777aabd07aae4d2dc126cb90c5a432b90/dictionaries/CallMap.php#L6860

[psalm-github-bot]

I found these snippets:

https://psalm.dev/r/6c64902528

<?php

mkdir("home/sample", 0755, true, null)

Psalm output (using commit 3600d51):

ERROR: ParseError - 3:39 - Syntax error, unexpected EOF on line 3

ERROR: NullArgument - 3:34 - Argument 4 of mkdir cannot be null, null value provided to parameter with type resource

[weirdan]

Note that PHP versions before 7.3 did not accept null: https://3v4l.org/APVEI