#64896 Tighten the documented types in WP_Hook

[johnbillion]

This adds a Hook_Callback PHPStan type to represent the shape of a callback used internally in WP_Hook and used in return values of array access methods.

Also narrows a few other documented types.

Trac ticket: https://core.trac.wordpress.org/ticket/64896
Trac ticket: https://core.trac.wordpress.org/ticket/64898

[github-actions]

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[westonruter]

I was looking into the other PHPStan rule level 10 issues in this file, and I found something related to the change you made here. It seems the offsetSet() method is lacking the use of the new type. I tried adding it:

--- a/src/wp-includes/class-wp-hook.php
+++ b/src/wp-includes/class-wp-hook.php
 	 *
 	 * @param mixed $offset The offset to assign the value to.
 	 * @param mixed $value The value to set.
+	 *
+	 * @phpstan-param array-key|null $offset
+	 * @phpstan-param array<string, Hook_Callback> $value
 	 */
 	#[ReturnTypeWillChange]
 	public function offsetSet( $offset, $value ) {

But there are two errors remaining here:

wordpress-develop/src/wp-includes/class-wp-hook.php

Lines 520 to 528 in 6e10867

	public function offsetSet( $offset, $value ) {
	if ( is_null( $offset ) ) {
	$this->callbacks[] = $value;
	} else {
	$this->callbacks[ $offset ] = $value;
	}
	$this->priorities = array_keys( $this->callbacks );
	}

At:

wordpress-develop/src/wp-includes/class-wp-hook.php

Line 524 in 6e10867

$this->callbacks[ $offset ] = $value;

phpstan: Property WP_Hook::$callbacks (array<int, array<string, array{function: callable(): mixed, accepted_args: int}>>) does not accept non-empty-array<int|string, array<string, array{function: callable(): mixed, accepted_args: int}>>.

And at:

wordpress-develop/src/wp-includes/class-wp-hook.php

Line 527 in 6e10867

$this->priorities = array_keys( $this->callbacks );

phpstan: Property WP_Hook::$priorities (list<int>) does not accept non-empty-list<int|string>.

[westonruter]

Addressed in 67f3a9b.

[westonruter]

I've followed up with #12443 to add b0d8b59 which fixes the remaining PHPStan level 10 errors in class-wp-hooks.php. If you don't want to include those fixes in your commit here, I can commit it separately.