Python 3.12.0b1: shutil.rmtree: DeprecationWarning: onerror argument is deprecated, use onexc instead

[Jun Omae]

The following is warned on invoking shutil.rmtree(onerror=...) with Python 3.12.

trac/test.py:555: DeprecationWarning: onerror argument is deprecated, use onexc instead
  shutil.rmtree(path, onerror=onerror)

See also: ​https://docs.python.org/3.12/library/shutil.html?highlight=onexc#shutil.rmtree

Patch:

trac/test.py

@@ -527 +527 @@
     return None
 
 
+if hasattr(inspect, 'getfullargspec'):  # Python 3.11+
+    _rmtree_argspec = inspect.getfullargspec(shutil.rmtree)
+    # onexc is added in Python 3.12 and onerror is deprecated
+    _rmtree_has_onexc = 'onexc' in getattr(_rmtree_argspec, 'kwonlyargs', [])
+    del _rmtree_argspec
+else:
+    _rmtree_has_onexc = False
+
+
 def rmtree(path):
     def onerror(function, path, excinfo, retry=1):
         # `os.unlink` and `os.remove` fail for a readonly file on Windows.
@@ -552 +561 @@
         # Use unicode characters in order to allow non-ansi characters
         # on Windows.
         path = str(path, sys.getfilesystemencoding())
-    shutil.rmtree(path, onerror=onerror)
+    kwargs = {'onexc' if _rmtree_has_onexc else 'onerror': onerror}
+    shutil.rmtree(path, **kwargs)
 
 
 INCLUDE_FUNCTIONAL_TESTS = True