If Renderer.__init__ raises before the rendering contexts are assigned
(e.g. width > offwidth raises ValueError, or MjrContext construction
fails), __del__ calls close() which accesses self._gl_context and
self._mjr_context unconditionally, raising AttributeError. This masks
the real __init__ failure with a noisy "Exception ignored in..." message
during garbage collection.
Pre-initialize both attributes to None at the top of __init__ so that
close() is safe on a partially-constructed instance. Add a regression
test that captures sys.unraisablehook and asserts that __del__ raises
nothing when __init__ fails via the width > offwidth path.
Fixes#3213.
devshahofficial
564007204c