From 04fea8c33fad75b204030de1ce6f783f7458233c Mon Sep 17 00:00:00 2001
From: Tim Hoffmann <2836374+timhoffm@users.noreply.github.com>
Date: Thu, 15 Aug 2024 15:04:26 +0200
Subject: [PATCH] MNT: Deprecate reimported functions in top-level namespace

---
 .../deprecations/28728-TH.rst                 | 10 ++++++++++
 lib/matplotlib/__init__.py                    | 20 +++++++++++++------
 2 files changed, 24 insertions(+), 6 deletions(-)
 create mode 100644 doc/api/next_api_changes/deprecations/28728-TH.rst

diff --git a/doc/api/next_api_changes/deprecations/28728-TH.rst b/doc/api/next_api_changes/deprecations/28728-TH.rst
new file mode 100644
index 000000000000..56d5a80b439c
--- /dev/null
+++ b/doc/api/next_api_changes/deprecations/28728-TH.rst
@@ -0,0 +1,10 @@
+matplotlib.validate_backend
+~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+...is deprecated. Please use `matplotlib.rcsetup.validate_backend` instead.
+
+
+matplotlib.sanitize_sequence
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+...is deprecated. Please use `matplotlib.cbook.sanitize_sequence` instead.
diff --git a/lib/matplotlib/__init__.py b/lib/matplotlib/__init__.py
index 8a77e5601d8c..6b5746ea0f16 100644
--- a/lib/matplotlib/__init__.py
+++ b/lib/matplotlib/__init__.py
@@ -157,10 +157,8 @@
 # cbook must import matplotlib only within function
 # definitions, so it is safe to import from it here.
 from . import _api, _version, cbook, _docstring, rcsetup
-from matplotlib.cbook import sanitize_sequence
 from matplotlib._api import MatplotlibDeprecationWarning
 from matplotlib.rcsetup import cycler  # noqa: F401
-from matplotlib.rcsetup import validate_backend
 
 
 _log = logging.getLogger(__name__)
@@ -1236,7 +1234,7 @@ def use(backend, *, force=True):
     matplotlib.pyplot.switch_backend
 
     """
-    name = validate_backend(backend)
+    name = rcsetup.validate_backend(backend)
     # don't (prematurely) resolve the "auto" backend setting
     if rcParams._get_backend_or_none() == name:
         # Nothing to do if the requested backend is already set
@@ -1340,7 +1338,7 @@ def _replacer(data, value):
     except Exception:
         # key does not exist, silently fall back to key
         pass
-    return sanitize_sequence(value)
+    return cbook.sanitize_sequence(value)
 
 
 def _label_from_arg(y, default_name):
@@ -1472,8 +1470,8 @@ def inner(ax, *args, data=None, **kwargs):
         if data is None:
             return func(
                 ax,
-                *map(sanitize_sequence, args),
-                **{k: sanitize_sequence(v) for k, v in kwargs.items()})
+                *map(cbook.sanitize_sequence, args),
+                **{k: cbook.sanitize_sequence(v) for k, v in kwargs.items()})
 
         bound = new_sig.bind(ax, *args, **kwargs)
         auto_label = (bound.arguments.get(label_namer)
@@ -1510,6 +1508,16 @@ def inner(ax, *args, data=None, **kwargs):
 _log.debug('platform is %s', sys.platform)
 
 
+@_api.deprecated("3.10", alternative="matplotlib.cbook.sanitize_sequence")
+def sanitize_sequence(data):
+    return cbook.sanitize_sequence(data)
+
+
+@_api.deprecated("3.10", alternative="matplotlib.rcsetup.validate_backend")
+def validate_backend(s):
+    return rcsetup.validate_backend(s)
+
+
 # workaround: we must defer colormaps import to after loading rcParams, because
 # colormap creation depends on rcParams
 from matplotlib.cm import _colormaps as colormaps  # noqa: E402