What is the WordPress multisite `switch_to_blog()` function’s impact on global state and what must always follow it?

Question

WordPress Expert — Hard

What is the WordPress multisite `switch_to_blog()` function’s impact on global state and what must always follow it?

Accepted Answer

The `switch_to_blog()` function in WordPress multisite changes the global $wpdb table prefix, flushes object caches, and sets the context to the specified site. It alters global variables like $wp_roles and $current_blog, so calling `restore_current_blog()` afterward is crucial to prevent targeting the wrong site.