diff --git a/lib/matplotlib/cbook/__init__.py b/lib/matplotlib/cbook/__init__.py
index 996e98f2c817..05631ef4ca45 100644
--- a/lib/matplotlib/cbook/__init__.py
+++ b/lib/matplotlib/cbook/__init__.py
@@ -2032,13 +2032,30 @@ def _setattr_cm(obj, **kwargs):
Temporarily set some attributes; restore original state at context exit.
"""
sentinel = object()
- origs = [(attr, getattr(obj, attr, sentinel)) for attr in kwargs]
+ origs = {}
+ for attr in kwargs:
+ orig = getattr(obj, attr, sentinel)
+
+ if attr in obj.__dict__ or orig is sentinel:
+ origs[attr] = orig
+ else:
+ cls_orig = getattr(type(obj), attr)
+ if isinstance(cls_orig, property):
+ origs[attr] = orig
+ elif isinstance(cls_orig, types.FunctionType):
+ origs[attr] = sentinel
+ else:
+ raise ValueError(
+ f"trying to set {attr} which is not a method, "
+ "property, or instance level attribute"
+ )
+
try:
for attr, val in kwargs.items():
setattr(obj, attr, val)
yield
finally:
- for attr, orig in origs:
+ for attr, orig in origs.items():
if orig is sentinel:
delattr(obj, attr)
else:
diff --git a/lib/matplotlib/tests/test_cbook.py b/lib/matplotlib/tests/test_cbook.py
index b1149fd24dc9..4e4457e2a392 100644
--- a/lib/matplotlib/tests/test_cbook.py
+++ b/lib/matplotlib/tests/test_cbook.py
@@ -651,3 +651,73 @@ def test_check_shape(target, test_shape):
with pytest.raises(ValueError,
match=error_pattern):
cbook._check_shape(target, aardvark=data)
+
+
+def test_setattr_cm():
+ class A:
+
+ cls_level = object()
+ override = object()
+ def __init__(self):
+ self.aardvark = 'aardvark'
+ self.override = 'override'
+ self._p = 'p'
+
+ def meth(self):
+ ...
+
+ @property
+ def prop(self):
+ return self._p
+
+ @prop.setter
+ def prop(self, val):
+ self._p = val
+
+ class B(A):
+ ...
+
+ other = A()
+
+ def verify_pre_post_state(obj):
+ # When you access a Python method the function is bound
+ # to the object at access time so you get a new instance
+ # of MethodType every time.
+ #
+ # https://docs.python.org/3/howto/descriptor.html#functions-and-methods
+ assert obj.meth is not obj.meth
+ # normal attribute should give you back the same instance every time
+ assert obj.aardvark is obj.aardvark
+ assert a.aardvark == 'aardvark'
+ # and our property happens to give the same instance every time
+ assert obj.prop is obj.prop
+ assert obj.cls_level is A.cls_level
+ assert obj.override == 'override'
+ assert not hasattr(obj, 'extra')
+ assert obj.prop == 'p'
+ assert obj.monkey == other.meth
+
+ a = B()
+
+ a.monkey = other.meth
+ verify_pre_post_state(a)
+ with cbook._setattr_cm(
+ a, prop='squirrel',
+ aardvark='moose', meth=lambda: None,
+ override='boo', extra='extra',
+ monkey=lambda: None):
+ # because we have set a lambda, it is normal attribute access
+ # and the same every time
+ assert a.meth is a.meth
+ assert a.aardvark is a.aardvark
+ assert a.aardvark == 'moose'
+ assert a.override == 'boo'
+ assert a.extra == 'extra'
+ assert a.prop == 'squirrel'
+ assert a.monkey != other.meth
+
+ verify_pre_post_state(a)
+
+ with pytest.raises(ValueError):
+ with cbook._setattr_cm(a, cls_level='bob'):
+ pass
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