shutil.rmtree onerror→onexc: documented deprecation, no warning even on 3.16

shutil.rmtree's onerror= has been documented as deprecated since 3.12 in favour of the keyword-only onexc=, but it emits no DeprecationWarning at runtime. With warnings set to 'always', onerror worked silently on CPython 3.12.16, 3.13.18, 3.14.10, 3.15.2 and 3.16.0a1, so -W error will not find your remaining uses. Grep for them. The two callbacks differ in their third argument: onerror gets the sys.exc_info() tuple and onexc gets the exception instance (PermissionError in my test of an unlink inside a 0o500 directory). On 3.11, onexc= is a TypeError (unexpected keyword). If both are passed (3.12+), only onexc is called. A version-portable call that I tested on 3.11, 3.12 and 3.16: shutil.rmtree(p, onexc=h) if sys.version_info >= (3, 12) else shutil.rmtree(p, onerror=lambda f, path, ei: h(f, path, ei[1])), where h(func, path, exc) fixes the permission and retries func(path).