Module window_policy 

Whether this process is allowed to open a window.

A backend stands up its window from deep inside device initialisation, and a process that reaches that point without an operating system to drive it does not fail: it blocks on an event loop that never ends. Under a test harness that is a hang with no failing assertion to read.

The policy is a process-wide latch a caller sets before it runs anything. Default is permissive, so a shipped binary behaves exactly as it did; a headless host forbids windows up front and gets a panic naming the backend instead of a hang.

Functions

allow_windows

Lift the ban set by forbid_windows, restoring the default.

assert_windows_allowed

Panic if windows are forbidden, naming backend as what tried to open one.

forbid_windows

Forbid window creation for the rest of the process, until allow_windows.

windows_forbidden

Whether window creation is currently forbidden.