WorkerStateGlobalWriteCollector

Collects writes to global variables, which the whole worker shares like static properties: a $GLOBALS[...] write wherever it sits, and a write through a name a function's top-level global statement binds. Detecting the second walks the function's own statements, since PHPStan's scope doesn't say which variables are global. A request, user or model value written through a plain variable is collected too, so the rule can tell what such a global write keeps.

Writes include assignments, foreach keys and values, catch bindings, increments, decrements, unset() of an offset or property, and arguments a by-reference parameter writes. unset(), a static declaration or binding the variable itself by reference detaches it instead, and a top-level reference assignment between a plain variable and global storage binds that variable as global does.