Use _api.caching_module_getattr for deprecated module-level attributes

Author: ianthomas23

lib/matplotlib/rcsetup.py

@@ -39,28 +39,25 @@
     BackendFilter.NON_INTERACTIVE)
 _deprecated_all_backends = backend_registry.list_builtin()
 
-_deprecated_names_and_args = {
-    "interactive_bk": "matplotlib.backends.registry.BackendFilter.INTERACTIVE",
-    "non_interactive_bk": "matplotlib.backends.registry.BackendFilter.NON_INTERACTIVE",
-    "all_backends": "",
-}
-
-
-def __getattr__(name):
-    if name in _deprecated_names_and_args:
-        arg = _deprecated_names_and_args[name]
-        _api.warn_deprecated(
-            "3.9.0",
-            name=name,
-            alternative="``matplotlib.backends.registry.backend_registry"
-                f".list_builtin({arg})``",
-        )
-        return globals()[f"_deprecated_{name}"]
-    raise AttributeError(f"module {__name__!r} has no attribute {name!r}")
-
 
-def __dir__():
-    return sorted(globals().keys() | _deprecated_names_and_args.keys())
+@_api.caching_module_getattr
+class __getattr__:
+    interactive_bk = _api.deprecated(
+        "3.9",
+        alternative="``matplotlib.backends.registry.backend_registry.list_builtin"
+            "(matplotlib.backends.registry.BackendFilter.INTERACTIVE)``"
+    )(property(lambda self: _deprecated_interactive_bk))
+
+    non_interactive_bk = _api.deprecated(
+        "3.9",
+        alternative="``matplotlib.backends.registry.backend_registry.list_builtin"
+            "(matplotlib.backends.registry.BackendFilter.NON_INTERACTIVE)``"
+    )(property(lambda self: _deprecated_non_interactive_bk))
+
+    all_backends = _api.deprecated(
+        "3.9",
+        alternative="``matplotlib.backends.registry.backend_registry.list_builtin()``"
+    )(property(lambda self: _deprecated_all_backends))
 
 
 class ValidateInStrings:

lib/matplotlib/tests/test_backend_registry.py

@@ -3,6 +3,7 @@
 
 import pytest
 
+import matplotlib as mpl
 from matplotlib.backends.registry import BackendFilter, backend_registry
 
 
@@ -54,3 +55,13 @@ def test_list_builtin_with_filter(filter, expected):
     assert not has_duplicates(backends)
     # Compare using sets as order is not important
     assert {*backends} == {*expected}
+
+
+def test_deprecated_rcsetup_attributes():
+    match = "was deprecated in Matplotlib 3.9"
+    with pytest.warns(mpl.MatplotlibDeprecationWarning, match=match):
+        mpl.rcsetup.interactive_bk
+    with pytest.warns(mpl.MatplotlibDeprecationWarning, match=match):
+        mpl.rcsetup.non_interactive_bk
+    with pytest.warns(mpl.MatplotlibDeprecationWarning, match=match):
+        mpl.rcsetup.all_backends