From ab1ea99718adf4eb5df73979acdafa86e2cf77f9 Mon Sep 17 00:00:00 2001
From: Chahak Mehta <chahakmehta013@gmail.com>
Date: Tue, 4 Apr 2023 16:36:04 -0500
Subject: [PATCH 01/22] Implement RcParams using ChainMaps.

---
 lib/matplotlib/__init__.py            | 251 +++++++++++++++++++-------
 lib/matplotlib/mpl-data/matplotlibrc  |  10 +-
 lib/matplotlib/pyplot.py              |  14 +-
 lib/matplotlib/rcsetup.py             |  10 +-
 lib/matplotlib/style/core.py          |   6 +-
 lib/matplotlib/tests/test_rcparams.py |   2 +-
 lib/matplotlib/tests/test_widgets.py  |   2 +-
 7 files changed, 210 insertions(+), 85 deletions(-)

diff --git a/lib/matplotlib/__init__.py b/lib/matplotlib/__init__.py
index 53f27c46314a..a55deeb912de 100644
--- a/lib/matplotlib/__init__.py
+++ b/lib/matplotlib/__init__.py
@@ -134,8 +134,8 @@
 
 
 import atexit
-from collections import namedtuple
-from collections.abc import MutableMapping
+from collections import namedtuple, ChainMap, defaultdict
+from collections.abc import MutableMapping, Mapping
 import contextlib
 import functools
 import importlib
@@ -155,6 +155,7 @@
 
 import numpy
 from packaging.version import parse as parse_version
+from copy import deepcopy
 
 # cbook must import matplotlib only within function
 # definitions, so it is safe to import from it here.
@@ -650,7 +651,7 @@ def gen_candidates():
 @_docstring.Substitution(
     "\n".join(map("- {}".format, sorted(rcsetup._validators, key=str.lower)))
 )
-class RcParams(MutableMapping, dict):
+class RcParams(MutableMapping):
     """
     A dict-like key-value store for config parameters, including validation.
 
@@ -665,14 +666,71 @@ class RcParams(MutableMapping, dict):
     --------
     :ref:`customizing-with-matplotlibrc-files`
     """
-
     validate = rcsetup._validators
+    namespaces = (
+        "backends",
+        "lines",
+        "patches",
+        "hatches",
+        "boxplot",
+        "font",
+        "text",
+        "latex",
+        "axes",
+        "date",
+        "xtick",
+        "ytick",
+        "grid",
+        "legend",
+        "figure",
+        "image",
+        "contour",
+        "errorbar",
+        "hist",
+        "scatter",
+        "agg",
+        "path",
+        "savefig",
+        "tk",
+        "ps",
+        "pdf",
+        "svg",
+        "pgf",
+        "docstring",
+        "keymap",
+        "animation",
+        "_internal",
+        "webagg",
+        "markers",
+        "pcolor",
+        "pcolormesh",
+        "patch",
+        "hatch",
+        "mathtext",
+        "polaraxes",
+        "axes3d",
+        "xaxis",
+        "yaxis",
+        "default"
+    )
+
+    single_key_set = {"backend", "toolbar", "interactive",
+                      "timezone", "backend_fallback"}
 
-    # validate values on the way in
     def __init__(self, *args, **kwargs):
+        self._namespace_maps = {name: ChainMap({}) for name in self.namespaces}
         self.update(*args, **kwargs)
+        self._namespace_maps = {
+            name: mapping.new_child()
+            for name, mapping in self._namespace_maps.items()
+        }
+        self._mapping = ChainMap(*self._namespace_maps.values())
 
-    def _set(self, key, val):
+    def _split_key(self, key, sep="."):
+        keys = key.split(sep, maxsplit=1)
+        return keys, len(keys)
+
+    def _set(self, key, value):
         """
         Directly write data bypassing deprecation and validation logic.
 
@@ -690,7 +748,13 @@ def _set(self, key, val):
 
         :meta public:
         """
-        dict.__setitem__(self, key, val)
+        keys, depth = self._split_key(key)
+        if depth == 1:
+            if key in self.single_key_set:
+                self._namespace_maps["default"][key] = value
+            self._namespace_maps[key] = value
+        elif depth == 2:
+            self._namespace_maps[keys[0]][keys[1]] = value
 
     def _get(self, key):
         """
@@ -711,7 +775,13 @@ def _get(self, key):
 
         :meta public:
         """
-        return dict.__getitem__(self, key)
+        keys, depth = self._split_key(key)
+        if depth == 1:
+            if key in self.single_key_set:
+                return self._namespace_maps["default"].get(key)
+            return self._namespace_maps[key]
+        elif depth == 2:
+            return self._namespace_maps[keys[0]].get(keys[1])
 
     def __setitem__(self, key, val):
         try:
@@ -733,10 +803,13 @@ def __setitem__(self, key, val):
                 if val is rcsetup._auto_backend_sentinel:
                     if 'backend' in self:
                         return
+            if key in self.single_key_set:
+                key = f"default.{key}"
             try:
                 cval = self.validate[key](val)
             except ValueError as ve:
                 raise ValueError(f"Key {key}: {ve}") from None
+            # breakpoint()
             self._set(key, cval)
         except KeyError as err:
             raise KeyError(
@@ -768,51 +841,97 @@ def __getitem__(self, key):
 
     def _get_backend_or_none(self):
         """Get the requested backend, if any, without triggering resolution."""
-        backend = self._get("backend")
+        backend = self._get("default.backend")
         return None if backend is rcsetup._auto_backend_sentinel else backend
 
-    def __repr__(self):
-        class_name = self.__class__.__name__
-        indent = len(class_name) + 1
-        with _api.suppress_matplotlib_deprecation_warning():
-            repr_split = pprint.pformat(dict(self), indent=1,
-                                        width=80 - indent).split('\n')
-        repr_indented = ('\n' + ' ' * indent).join(repr_split)
-        return f'{class_name}({repr_indented})'
-
-    def __str__(self):
-        return '\n'.join(map('{0[0]}: {0[1]}'.format, sorted(self.items())))
+    def __delitem__(self, key):
+        keys, depth = self._split_key(key)
+        if depth == 1:
+            del self._namespace_maps[key]
+        elif depth == 2:
+            del self._namespace_maps[keys[0]][keys[1]]
+
+    def __contains__(self, key):
+        keys, depth = self._split_key(key)
+        if depth == 1:
+            if key in self.single_key_set:
+                return key in self._namespace_maps["default"]
+            return key in self._namespace_maps
+        elif depth == 2:
+            return any(key in mapping for mapping in self._namespace_maps)
 
     def __iter__(self):
-        """Yield sorted list of keys."""
+        """Yield from sorted list of keys"""
         with _api.suppress_matplotlib_deprecation_warning():
-            yield from sorted(dict.__iter__(self))
+            yield from sorted(self.keys())
 
     def __len__(self):
-        return dict.__len__(self)
-
-    def find_all(self, pattern):
-        """
-        Return the subset of this RcParams dictionary whose keys match,
-        using :func:`re.search`, the given ``pattern``.
-
-        .. note::
-
-            Changes to the returned dictionary are *not* propagated to
-            the parent RcParams dictionary.
+        return sum(len(mapping) for mapping in self._namespace_maps)
 
+    def __repr__(self):
+        return repr(dict(self.items()))
+
+    def keys(self):
+        keys = (
+            ".".join((space, key))
+            for space, mapping in self._namespace_maps.items()
+            for key in mapping.keys()
+        )
+        return keys
+
+    def values(self):
+        for key in self.keys():
+            yield self[key]
+
+    def items(self):
+        for key, value in zip(self.keys(), self.values()):
+            yield key, value
+
+    def pop(self, key):
+        keys, depth = self._split_key(key)
+        if depth == 1:
+            self._mapping.pop()
+        elif depth == 2:
+            self._namespace_mapping[keys[0]].pop(keys[1])
+
+    def popitem(self):
+        return self._mapping.popitem()
+
+    def clear(self):
+        self._mapping.clear()
+
+    def setdefault(self, key, default=None):
+        self[key] = default
+        return default
+
+    def get(self, key, default=None):
+        try:
+            return self[key]
+        except KeyError as e:
+            return default
+
+    def update(self, other=(), /, **kwds):
+        """D.update([E, ]**F) -> None.  Update D from mapping/iterable E and F.
+        If E present and has a .keys() method, does:     for k in E: D[k] = E[k]
+        If E present and lacks .keys() method, does:     for (k, v) in E: D[k] = v
+        In either case, this is followed by: for k, v in F.items(): D[k] = v
         """
-        pattern_re = re.compile(pattern)
-        return RcParams((key, value)
-                        for key, value in self.items()
-                        if pattern_re.search(key))
+        if isinstance(other, Mapping):
+            for key in other:
+                self[key] = other[key]
+        elif hasattr(other, "keys"):
+            for key in other.keys():
+                self[key] = other[key]
+        else:
+            for key, value in other:
+                self[key] = value
+        for key, value in kwds.items():
+            self[key] = value
 
     def copy(self):
-        """Copy this RcParams instance."""
-        rccopy = RcParams()
-        for k in self:  # Skip deprecations and revalidation.
-            rccopy._set(k, self._get(k))
-        return rccopy
+        return deepcopy(self)
+
+# MutableMapping.register(RcParams)
 
 
 def rc_params(fail_on_error=False):
@@ -962,36 +1081,34 @@ def rc_params_from_file(fname, fail_on_error=False, use_default_template=True):
     return config
 
 
-# When constructing the global instances, we need to perform certain updates
-# by explicitly calling the superclass (dict.update, dict.items) to avoid
-# triggering resolution of _auto_backend_sentinel.
 rcParamsDefault = _rc_params_in_file(
     cbook._get_data_path("matplotlibrc"),
     # Strip leading comment.
     transform=lambda line: line[1:] if line.startswith("#") else line,
     fail_on_error=True)
-dict.update(rcParamsDefault, rcsetup._hardcoded_defaults)
+rcParamsDefault.update(rcsetup._hardcoded_defaults)
 # Normally, the default matplotlibrc file contains *no* entry for backend (the
 # corresponding line starts with ##, not #; we fill on _auto_backend_sentinel
 # in that case.  However, packagers can set a different default backend
 # (resulting in a normal `#backend: foo` line) in which case we should *not*
 # fill in _auto_backend_sentinel.
-dict.setdefault(rcParamsDefault, "backend", rcsetup._auto_backend_sentinel)
-rcParams = RcParams()  # The global instance.
-dict.update(rcParams, dict.items(rcParamsDefault))
-dict.update(rcParams, _rc_params_in_file(matplotlib_fname()))
-rcParamsOrig = rcParams.copy()
+rcParamsDefault.setdefault("default.backend", rcsetup._auto_backend_sentinel)
+params_dict = RcParams()
+params_dict.update(rcParamsDefault.items())
+params_dict.update(_rc_params_in_file(matplotlib_fname()))
+rcParamsOrig = params_dict.copy()
 with _api.suppress_matplotlib_deprecation_warning():
     # This also checks that all rcParams are indeed listed in the template.
     # Assigning to rcsetup.defaultParams is left only for backcompat.
     defaultParams = rcsetup.defaultParams = {
         # We want to resolve deprecated rcParams, but not backend...
-        key: [(rcsetup._auto_backend_sentinel if key == "backend" else
+        key: [(rcsetup._auto_backend_sentinel if key == "default.backend" else
                rcParamsDefault[key]),
               validator]
         for key, validator in rcsetup._validators.items()}
-if rcParams['axes.formatter.use_locale']:
+if params_dict['axes.formatter.use_locale']:
     locale.setlocale(locale.LC_ALL, '')
+rcParams = RcParams(params_dict)
 
 
 def rc(group, **kwargs):
@@ -1133,7 +1250,7 @@ def rc_file(fname, *, use_default_template=True):
         from .style.core import STYLE_BLACKLIST
         rc_from_file = rc_params_from_file(
             fname, use_default_template=use_default_template)
-        rcParams.update({k: rc_from_file[k] for k in rc_from_file
+        rcParams.update({k: rc_from_file[k] for k in rc_from_file.keys()
                          if k not in STYLE_BLACKLIST})
 
 
@@ -1182,16 +1299,24 @@ def rc_context(rc=None, fname=None):
             plt.plot(x, y)
 
     """
-    orig = dict(rcParams.copy())
-    del orig['backend']
     try:
+        for space in rcParams._namespace_maps.keys():
+            rcParams._namespace_maps[space] = rcParams._namespace_maps[
+                space
+            ].new_child()
         if fname:
             rc_file(fname)
         if rc:
             rcParams.update(rc)
         yield
     finally:
-        dict.update(rcParams, orig)  # Revert to the original rcs.
+        # Revert to the original rcs.
+        backend = rcParams["backend"]
+        for space in rcParams._namespace_maps.keys():
+            rcParams._namespace_maps[space] = rcParams._namespace_maps[
+                space
+            ].parents
+        rcParams["backend"] = backend
 
 
 def use(backend, *, force=True):
@@ -1259,14 +1384,14 @@ def use(backend, *, force=True):
         # value which will be respected when the user finally imports
         # pyplot
         else:
-            rcParams['backend'] = backend
+            rcParams['default.backend'] = backend
     # if the user has asked for a given backend, do not helpfully
     # fallback
-    rcParams['backend_fallback'] = False
+    rcParams['default.backend_fallback'] = False
 
 
 if os.environ.get('MPLBACKEND'):
-    rcParams['backend'] = os.environ.get('MPLBACKEND')
+    rcParams['default.backend'] = os.environ.get('MPLBACKEND')
 
 
 def get_backend():
@@ -1277,14 +1402,14 @@ def get_backend():
     --------
     matplotlib.use
     """
-    return rcParams['backend']
+    return rcParams['default.backend']
 
 
 def interactive(b):
     """
     Set whether to redraw after every plotting command (e.g. `.pyplot.xlabel`).
     """
-    rcParams['interactive'] = b
+    rcParams['default.interactive'] = b
 
 
 def is_interactive():
@@ -1296,7 +1421,7 @@ def is_interactive():
         This function is only intended for use in backends. End users should
         use `.pyplot.isinteractive` instead.
     """
-    return rcParams['interactive']
+    return rcParams['default.interactive']
 
 
 def _val_or_rc(val, rc_name):
diff --git a/lib/matplotlib/mpl-data/matplotlibrc b/lib/matplotlib/mpl-data/matplotlibrc
index 9bd8a622092e..25e6aaa00d4d 100644
--- a/lib/matplotlib/mpl-data/matplotlibrc
+++ b/lib/matplotlib/mpl-data/matplotlibrc
@@ -82,7 +82,7 @@
 ##     PS PDF SVG Template
 ## You can also deploy your own backend outside of Matplotlib by referring to
 ## the module name (which must be in the PYTHONPATH) as 'module://my_backend'.
-##backend: Agg
+##default.backend: Agg
 
 ## The port to use for the web server in the WebAgg backend.
 #webagg.port: 8988
@@ -100,12 +100,12 @@
 ## If you are running pyplot inside a GUI and your backend choice
 ## conflicts, we will automatically try to find a compatible one for
 ## you if backend_fallback is True
-#backend_fallback: True
+#default.backend_fallback: True
 
-#interactive: False
+#default.interactive: False
 #figure.hooks:          # list of dotted.module.name:dotted.callable.name
-#toolbar:     toolbar2  # {None, toolbar2, toolmanager}
-#timezone:    UTC       # a pytz timezone string, e.g., US/Central or Europe/Paris
+#default.toolbar:     toolbar2  # {None, toolbar2, toolmanager}
+#default.timezone:    UTC       # a pytz timezone string, e.g., US/Central or Europe/Paris
 
 
 ## ***************************************************************************
diff --git a/lib/matplotlib/pyplot.py b/lib/matplotlib/pyplot.py
index 7f4aa12c9ed6..e815ddb1b347 100644
--- a/lib/matplotlib/pyplot.py
+++ b/lib/matplotlib/pyplot.py
@@ -327,16 +327,16 @@ def switch_backend(newbackend: str) -> None:
             except ImportError:
                 continue
             else:
-                rcParamsOrig['backend'] = candidate
+                rcParamsOrig['default.backend'] = candidate
                 return
         else:
             # Switching to Agg should always succeed; if it doesn't, let the
             # exception propagate out.
             switch_backend("agg")
-            rcParamsOrig["backend"] = "agg"
+            rcParamsOrig["default.backend"] = "agg"
             return
     # have to escape the switch on access logic
-    old_backend = dict.__getitem__(rcParams, 'backend')
+    old_backend = rcParams['default.backend']
 
     module = importlib.import_module(cbook._backend_module_name(newbackend))
     canvas_class = module.FigureCanvas
@@ -413,7 +413,7 @@ def draw_if_interactive() -> None:
     _log.debug("Loaded backend %s version %s.",
                newbackend, backend_mod.backend_version)
 
-    rcParams['backend'] = rcParamsDefault['backend'] = newbackend
+    rcParams['default.backend'] = rcParamsDefault['default.backend'] = newbackend
     _backend_mod = backend_mod
     for func_name in ["new_figure_manager", "draw_if_interactive", "show"]:
         globals()[func_name].__signature__ = inspect.signature(
@@ -745,7 +745,7 @@ def xkcd(
             "xkcd mode is not compatible with text.usetex = True")
 
     stack = ExitStack()
-    stack.callback(dict.update, rcParams, rcParams.copy())  # type: ignore
+    stack.callback(rcParams.update, rcParams.copy()) # type: ignore
 
     from matplotlib import patheffects
     rcParams.update({
@@ -2472,11 +2472,11 @@ def polar(*args, **kwargs) -> list[Line2D]:
 # If rcParams['backend_fallback'] is true, and an interactive backend is
 # requested, ignore rcParams['backend'] and force selection of a backend that
 # is compatible with the current running interactive framework.
-if (rcParams["backend_fallback"]
+if (rcParams["default.backend_fallback"]
         and rcParams._get_backend_or_none() in (  # type: ignore
             set(rcsetup.interactive_bk) - {'WebAgg', 'nbAgg'})
         and cbook._get_running_interactive_framework()):  # type: ignore
-    rcParams._set("backend", rcsetup._auto_backend_sentinel)  # type: ignore
+    rcParams._set("default.backend", rcsetup._auto_backend_sentinel)  # type: ignore
 
 # fmt: on
 
diff --git a/lib/matplotlib/rcsetup.py b/lib/matplotlib/rcsetup.py
index 38d4606024d3..bee0204a46b9 100644
--- a/lib/matplotlib/rcsetup.py
+++ b/lib/matplotlib/rcsetup.py
@@ -892,12 +892,12 @@ def _convert_validator_spec(key, conv):
 # The rcParams defaults are defined in lib/matplotlib/mpl-data/matplotlibrc, which
 # gets copied to matplotlib/mpl-data/matplotlibrc by the setup script.
 _validators = {
-    "backend":           validate_backend,
-    "backend_fallback":  validate_bool,
+    "default.backend":           validate_backend,
+    "default.backend_fallback":  validate_bool,
     "figure.hooks":      validate_stringlist,
-    "toolbar":           _validate_toolbar,
-    "interactive":       validate_bool,
-    "timezone":          validate_string,
+    "default.toolbar":           _validate_toolbar,
+    "default.interactive":       validate_bool,
+    "default.timezone":          validate_string,
 
     "webagg.port":            validate_int,
     "webagg.address":         validate_string,
diff --git a/lib/matplotlib/style/core.py b/lib/matplotlib/style/core.py
index 7e9008c56165..57ea5fa5df1d 100644
--- a/lib/matplotlib/style/core.py
+++ b/lib/matplotlib/style/core.py
@@ -39,9 +39,9 @@
 STYLE_EXTENSION = 'mplstyle'
 # A list of rcParams that should not be applied from styles
 STYLE_BLACKLIST = {
-    'interactive', 'backend', 'webagg.port', 'webagg.address',
-    'webagg.port_retries', 'webagg.open_in_browser', 'backend_fallback',
-    'toolbar', 'timezone', 'figure.max_open_warning',
+    'default.interactive', 'default.backend', 'webagg.port', 'webagg.address',
+    'webagg.port_retries', 'webagg.open_in_browser', 'default.backend_fallback',
+    'default.toolbar', 'default.timezone', 'figure.max_open_warning',
     'figure.raise_window', 'savefig.directory', 'tk.window_focus',
     'docstring.hardcopy', 'date.epoch'}
 
diff --git a/lib/matplotlib/tests/test_rcparams.py b/lib/matplotlib/tests/test_rcparams.py
index 65cd823f13a9..609e80bb4138 100644
--- a/lib/matplotlib/tests/test_rcparams.py
+++ b/lib/matplotlib/tests/test_rcparams.py
@@ -199,7 +199,7 @@ def test_axes_titlecolor_rcparams():
 
 def test_Issue_1713(tmpdir):
     rcpath = Path(tmpdir) / 'test_rcparams.rc'
-    rcpath.write_text('timezone: UTC', encoding='utf-8')
+    rcpath.write_text('default.timezone: UTC', encoding='utf-8')
     with mock.patch('locale.getpreferredencoding', return_value='UTF-32-BE'):
         rc = mpl.rc_params_from_file(rcpath, True, False)
     assert rc.get('timezone') == 'UTC'
diff --git a/lib/matplotlib/tests/test_widgets.py b/lib/matplotlib/tests/test_widgets.py
index de17bb79bd4b..b96c5693f6a2 100644
--- a/lib/matplotlib/tests/test_widgets.py
+++ b/lib/matplotlib/tests/test_widgets.py
@@ -1029,7 +1029,7 @@ def test_CheckButtons(ax):
 @pytest.mark.parametrize("toolbar", ["none", "toolbar2", "toolmanager"])
 def test_TextBox(ax, toolbar):
     # Avoid "toolmanager is provisional" warning.
-    plt.rcParams._set("toolbar", toolbar)
+    plt.rcParams._set("default.toolbar", toolbar)
 
     submit_event = mock.Mock(spec=noop, return_value=None)
     text_change_event = mock.Mock(spec=noop, return_value=None)

From 517750871872d7404f8e296d39dc2bb3cb625287 Mon Sep 17 00:00:00 2001
From: Chahak Mehta <chahakmehta013@gmail.com>
Date: Tue, 4 Apr 2023 16:52:51 -0500
Subject: [PATCH 02/22] Make namespaces variable compact

---
 lib/matplotlib/__init__.py | 53 +++++---------------------------------
 1 file changed, 7 insertions(+), 46 deletions(-)

diff --git a/lib/matplotlib/__init__.py b/lib/matplotlib/__init__.py
index a55deeb912de..22cc9a3cec8d 100644
--- a/lib/matplotlib/__init__.py
+++ b/lib/matplotlib/__init__.py
@@ -667,52 +667,13 @@ class RcParams(MutableMapping):
     :ref:`customizing-with-matplotlibrc-files`
     """
     validate = rcsetup._validators
-    namespaces = (
-        "backends",
-        "lines",
-        "patches",
-        "hatches",
-        "boxplot",
-        "font",
-        "text",
-        "latex",
-        "axes",
-        "date",
-        "xtick",
-        "ytick",
-        "grid",
-        "legend",
-        "figure",
-        "image",
-        "contour",
-        "errorbar",
-        "hist",
-        "scatter",
-        "agg",
-        "path",
-        "savefig",
-        "tk",
-        "ps",
-        "pdf",
-        "svg",
-        "pgf",
-        "docstring",
-        "keymap",
-        "animation",
-        "_internal",
-        "webagg",
-        "markers",
-        "pcolor",
-        "pcolormesh",
-        "patch",
-        "hatch",
-        "mathtext",
-        "polaraxes",
-        "axes3d",
-        "xaxis",
-        "yaxis",
-        "default"
-    )
+    namespaces = ("backends", "lines", "patches", "hatches", "boxplot", "font", "text",
+                  "latex", "axes", "date", "xtick", "ytick", "grid", "legend",
+                  "figure", "image", "contour", "errorbar", "hist", "scatter", "agg",
+                  "path", "savefig", "tk", "ps", "pdf", "svg", "pgf", "docstring",
+                  "keymap", "animation", "_internal", "webagg", "markers", "pcolor",
+                  "pcolormesh", "patch", "hatch", "mathtext", "polaraxes", "axes3d",
+                  "xaxis", "yaxis", "default")
 
     single_key_set = {"backend", "toolbar", "interactive",
                       "timezone", "backend_fallback"}

From 45d4743b960c00bfc65b183ba30f2e70a0fcca71 Mon Sep 17 00:00:00 2001
From: Chahak Mehta <chahakmehta013@gmail.com>
Date: Thu, 13 Apr 2023 20:43:26 -0500
Subject: [PATCH 03/22] Raise KeyError when accessing namespace for now.

---
 lib/matplotlib/__init__.py | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/lib/matplotlib/__init__.py b/lib/matplotlib/__init__.py
index 22cc9a3cec8d..e71e351bd4ce 100644
--- a/lib/matplotlib/__init__.py
+++ b/lib/matplotlib/__init__.py
@@ -740,7 +740,13 @@ def _get(self, key):
         if depth == 1:
             if key in self.single_key_set:
                 return self._namespace_maps["default"].get(key)
-            return self._namespace_maps[key]
+            # Comment the following line and remove the raise statement
+            # to enable getting namespace parameters.
+            # return self._namespace_maps[key]
+            else:
+                raise KeyError(
+                    f"{key} is not a valid rc parameter (see rcParams.keys() for "
+                    f"a list of valid parameters)")
         elif depth == 2:
             return self._namespace_maps[keys[0]].get(keys[1])
 
@@ -770,7 +776,6 @@ def __setitem__(self, key, val):
                 cval = self.validate[key](val)
             except ValueError as ve:
                 raise ValueError(f"Key {key}: {ve}") from None
-            # breakpoint()
             self._set(key, cval)
         except KeyError as err:
             raise KeyError(

From 133f2af557178644f8e83474872f69869ed2063b Mon Sep 17 00:00:00 2001
From: Chahak Mehta <chahakmehta013@gmail.com>
Date: Thu, 13 Apr 2023 20:54:24 -0500
Subject: [PATCH 04/22] Make linter happy

---
 lib/matplotlib/pyplot.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/matplotlib/pyplot.py b/lib/matplotlib/pyplot.py
index e815ddb1b347..a2b5190fff67 100644
--- a/lib/matplotlib/pyplot.py
+++ b/lib/matplotlib/pyplot.py
@@ -745,7 +745,7 @@ def xkcd(
             "xkcd mode is not compatible with text.usetex = True")
 
     stack = ExitStack()
-    stack.callback(rcParams.update, rcParams.copy()) # type: ignore
+    stack.callback(rcParams.update, rcParams.copy())  # type: ignore
 
     from matplotlib import patheffects
     rcParams.update({

From b7f4fb5cb8878fba9528808d4660c184d1529c7c Mon Sep 17 00:00:00 2001
From: Chahak Mehta <chahakmehta013@gmail.com>
Date: Fri, 14 Apr 2023 11:46:47 -0500
Subject: [PATCH 05/22] Update repr, str and add find_all

---
 lib/matplotlib/__init__.py | 27 +++++++++++++++++++++++++--
 1 file changed, 25 insertions(+), 2 deletions(-)

diff --git a/lib/matplotlib/__init__.py b/lib/matplotlib/__init__.py
index e71e351bd4ce..c4f93d99f131 100644
--- a/lib/matplotlib/__init__.py
+++ b/lib/matplotlib/__init__.py
@@ -835,7 +835,16 @@ def __len__(self):
         return sum(len(mapping) for mapping in self._namespace_maps)
 
     def __repr__(self):
-        return repr(dict(self.items()))
+        class_name = self.__class__.__name__
+        indent = len(class_name) + 1
+        with _api.suppress_matplotlib_deprecation_warning():
+            repr_split = pprint.pformat(dict(self.items()), indent=1,
+                                        width=80 - indent).split('\n')
+        repr_indented = ('\n' + ' ' * indent).join(repr_split)
+        return f'{class_name}({repr_indented})'
+
+    def __str__(self):
+        return '\n'.join(map('{0[0]}: {0[1]}'.format, sorted(self.items())))
 
     def keys(self):
         keys = (
@@ -897,7 +906,21 @@ def update(self, other=(), /, **kwds):
     def copy(self):
         return deepcopy(self)
 
-# MutableMapping.register(RcParams)
+    def find_all(self, pattern):
+        """
+        Return the subset of this RcParams dictionary whose keys match,
+        using :func:`re.search`, the given ``pattern``.
+
+        .. note::
+
+            Changes to the returned dictionary are *not* propagated to
+            the parent RcParams dictionary.
+
+        """
+        pattern_re = re.compile(pattern)
+        return RcParams((key, value)
+                        for key, value in self.items()
+                        if pattern_re.search(key))
 
 
 def rc_params(fail_on_error=False):

From d135342b1c448bd7b82806c863662b4071f896c1 Mon Sep 17 00:00:00 2001
From: Chahak Mehta <chahakmehta013@gmail.com>
Date: Sun, 16 Apr 2023 22:08:07 -0500
Subject: [PATCH 06/22] Fix issue resolve testing backend

---
 lib/matplotlib/__init__.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/matplotlib/__init__.py b/lib/matplotlib/__init__.py
index c4f93d99f131..14ee36f05d7a 100644
--- a/lib/matplotlib/__init__.py
+++ b/lib/matplotlib/__init__.py
@@ -766,7 +766,7 @@ def __setitem__(self, key, val):
                 _api.warn_deprecated(
                     version, name=key, obj_type="rcparam", alternative=alt_key)
                 return
-            elif key == 'backend':
+            elif key == 'backend' or key == "default.backend":
                 if val is rcsetup._auto_backend_sentinel:
                     if 'backend' in self:
                         return
@@ -1391,7 +1391,7 @@ def get_backend():
     --------
     matplotlib.use
     """
-    return rcParams['default.backend']
+    return rcParams['backend']
 
 
 def interactive(b):

From 47b48ee2282f5e66ac1f5990a9c69fa679d239a3 Mon Sep 17 00:00:00 2001
From: Chahak Mehta <chahakmehta013@gmail.com>
Date: Mon, 17 Apr 2023 16:51:32 -0500
Subject: [PATCH 07/22] Update a few functions in RcParams

---
 lib/matplotlib/__init__.py           | 62 +++++++++++++++++++++-------
 lib/matplotlib/mpl-data/matplotlibrc | 10 ++---
 2 files changed, 51 insertions(+), 21 deletions(-)

diff --git a/lib/matplotlib/__init__.py b/lib/matplotlib/__init__.py
index 14ee36f05d7a..4a4cbd6ca061 100644
--- a/lib/matplotlib/__init__.py
+++ b/lib/matplotlib/__init__.py
@@ -134,7 +134,7 @@
 
 
 import atexit
-from collections import namedtuple, ChainMap, defaultdict
+from collections import namedtuple, ChainMap
 from collections.abc import MutableMapping, Mapping
 import contextlib
 import functools
@@ -691,7 +691,7 @@ def _split_key(self, key, sep="."):
         keys = key.split(sep, maxsplit=1)
         return keys, len(keys)
 
-    def _set(self, key, value):
+    def _set(self, key, val):
         """
         Directly write data bypassing deprecation and validation logic.
 
@@ -712,10 +712,22 @@ def _set(self, key, value):
         keys, depth = self._split_key(key)
         if depth == 1:
             if key in self.single_key_set:
-                self._namespace_maps["default"][key] = value
-            self._namespace_maps[key] = value
+                self._namespace_maps["default"][key] = val
+            # Uncomment the following line and remove the raise statement
+            # to enable setting namespaces.
+            # else:
+            #     if isinstance(val, dict):
+            #         self._namespace_maps[key] = ChainMap({}, val)
+            #     else:
+            #         raise ValueError(
+            #             f"{key} should be set using a dictionary but found "
+            #             f"{type(val)}")
+            else:
+                raise KeyError(
+                    f"{key} is not a valid rc parameter (see rcParams.keys() for "
+                    f"a list of valid parameters)")
         elif depth == 2:
-            self._namespace_maps[keys[0]][keys[1]] = value
+            self._namespace_maps[keys[0]][keys[1]] = val
 
     def _get(self, key):
         """
@@ -740,7 +752,7 @@ def _get(self, key):
         if depth == 1:
             if key in self.single_key_set:
                 return self._namespace_maps["default"].get(key)
-            # Comment the following line and remove the raise statement
+            # Uncomment the following line and remove the raise statement
             # to enable getting namespace parameters.
             # return self._namespace_maps[key]
             else:
@@ -807,22 +819,31 @@ def __getitem__(self, key):
 
     def _get_backend_or_none(self):
         """Get the requested backend, if any, without triggering resolution."""
-        backend = self._get("default.backend")
+        backend = self._get("backend")
         return None if backend is rcsetup._auto_backend_sentinel else backend
 
     def __delitem__(self, key):
         keys, depth = self._split_key(key)
-        if depth == 1:
-            del self._namespace_maps[key]
-        elif depth == 2:
-            del self._namespace_maps[keys[0]][keys[1]]
+        try:
+            if depth == 1:
+                if key in self.single_key_set:
+                    del self._namespace_maps["default"][key]
+                else:
+                    raise KeyError
+            elif depth == 2:
+                del self._namespace_maps[keys[0]][keys[1]]
+        except KeyError as err:
+            raise KeyError(
+                f"{key} is not a valid rc parameter (see rcParams.keys() for "
+                f"a list of valid parameters)") from err
 
     def __contains__(self, key):
         keys, depth = self._split_key(key)
         if depth == 1:
             if key in self.single_key_set:
                 return key in self._namespace_maps["default"]
-            return key in self._namespace_maps
+            else:
+                return False
         elif depth == 2:
             return any(key in mapping for mapping in self._namespace_maps)
 
@@ -865,15 +886,22 @@ def items(self):
     def pop(self, key):
         keys, depth = self._split_key(key)
         if depth == 1:
-            self._mapping.pop()
+            if key in self.single_key_set:
+                return self._namespace_mapping["default"][key]
+            else:
+                raise KeyError(
+                    f"{key} is not a valid rc parameter (see rcParams.keys() for "
+                    f"a list of valid parameters)")
         elif depth == 2:
-            self._namespace_mapping[keys[0]].pop(keys[1])
+            return self._namespace_mapping[keys[0]].pop(keys[1])
 
     def popitem(self):
-        return self._mapping.popitem()
+        raise NotImplementedError(
+            "popitem is not implemented for RcParams.")
 
     def clear(self):
-        self._mapping.clear()
+        for namespace in self._namespace_maps:
+            self._namespace_maps[namespace].clear()
 
     def setdefault(self, key, default=None):
         self[key] = default
@@ -1005,6 +1033,8 @@ def _rc_params_in_file(fname, transform=lambda x: x, fail_on_error=False):
     config = RcParams()
 
     for key, (val, line, line_no) in rc_temp.items():
+        if key in config.single_key_set:
+            key = f"default.{key}"
         if key in rcsetup._validators:
             if fail_on_error:
                 config[key] = val  # try to convert to proper type or raise
diff --git a/lib/matplotlib/mpl-data/matplotlibrc b/lib/matplotlib/mpl-data/matplotlibrc
index 25e6aaa00d4d..9bd8a622092e 100644
--- a/lib/matplotlib/mpl-data/matplotlibrc
+++ b/lib/matplotlib/mpl-data/matplotlibrc
@@ -82,7 +82,7 @@
 ##     PS PDF SVG Template
 ## You can also deploy your own backend outside of Matplotlib by referring to
 ## the module name (which must be in the PYTHONPATH) as 'module://my_backend'.
-##default.backend: Agg
+##backend: Agg
 
 ## The port to use for the web server in the WebAgg backend.
 #webagg.port: 8988
@@ -100,12 +100,12 @@
 ## If you are running pyplot inside a GUI and your backend choice
 ## conflicts, we will automatically try to find a compatible one for
 ## you if backend_fallback is True
-#default.backend_fallback: True
+#backend_fallback: True
 
-#default.interactive: False
+#interactive: False
 #figure.hooks:          # list of dotted.module.name:dotted.callable.name
-#default.toolbar:     toolbar2  # {None, toolbar2, toolmanager}
-#default.timezone:    UTC       # a pytz timezone string, e.g., US/Central or Europe/Paris
+#toolbar:     toolbar2  # {None, toolbar2, toolmanager}
+#timezone:    UTC       # a pytz timezone string, e.g., US/Central or Europe/Paris
 
 
 ## ***************************************************************************

From 9a0854487040b8827a353c1f0aa00ea72898078a Mon Sep 17 00:00:00 2001
From: Chahak Mehta <chahakmehta013@gmail.com>
Date: Mon, 17 Apr 2023 17:26:17 -0500
Subject: [PATCH 08/22] Update type stubs

---
 lib/matplotlib/__init__.pyi | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/lib/matplotlib/__init__.pyi b/lib/matplotlib/__init__.pyi
index 8ef23a3dc4c2..1bbef561b9e4 100644
--- a/lib/matplotlib/__init__.pyi
+++ b/lib/matplotlib/__init__.pyi
@@ -65,13 +65,21 @@ def get_cachedir() -> str: ...
 def get_data_path() -> str: ...
 def matplotlib_fname() -> str: ...
 
-class RcParams(dict[str, Any]):
+class RcParams(MutableMapping):
     validate: dict[str, Callable]
+    namespaces: tuple
+    single_key_set: set
     def __init__(self, *args, **kwargs) -> None: ...
+    def _split_key(self, key: str, sep: str = ".") -> tuple[list, int]: ...
+    def _set(self, key: str, val: Any) -> None: ...
+    def _get(self, key: str) -> Any: ...
     def __setitem__(self, key: str, val: Any) -> None: ...
     def __getitem__(self, key: str) -> Any: ...
+    def __delitem__(self, key: str) -> None: ...
     def __iter__(self) -> Generator[str, None, None]: ...
     def __len__(self) -> int: ...
+    def keys(self) -> Generator[str, None, None]: ...
+    def values(self) -> Generator[Any, None, None]: ...
     def find_all(self, pattern: str) -> RcParams: ...
     def copy(self) -> RcParams: ...
 

From 9a0ad032f586539d1c4239c46deb5ea1a8756964 Mon Sep 17 00:00:00 2001
From: Chahak Mehta <chahakmehta013@gmail.com>
Date: Mon, 24 Apr 2023 21:41:45 -0500
Subject: [PATCH 09/22] Cache splitting keys.

---
 lib/matplotlib/__init__.py | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/lib/matplotlib/__init__.py b/lib/matplotlib/__init__.py
index 4a4cbd6ca061..18fa9906b4f6 100644
--- a/lib/matplotlib/__init__.py
+++ b/lib/matplotlib/__init__.py
@@ -685,9 +685,10 @@ def __init__(self, *args, **kwargs):
             name: mapping.new_child()
             for name, mapping in self._namespace_maps.items()
         }
-        self._mapping = ChainMap(*self._namespace_maps.values())
 
-    def _split_key(self, key, sep="."):
+    @staticmethod
+    @functools.lru_cache
+    def _split_key(key, sep="."):
         keys = key.split(sep, maxsplit=1)
         return keys, len(keys)
 

From 7a11e81abe38615f220eaba74a05f2bcc297a996 Mon Sep 17 00:00:00 2001
From: Chahak Mehta <chahakmehta013@gmail.com>
Date: Tue, 25 Apr 2023 21:11:29 -0500
Subject: [PATCH 10/22] Return views for .keys(), .values(), .items()

---
 lib/matplotlib/__init__.py  | 25 +++++++------------------
 lib/matplotlib/__init__.pyi |  4 +---
 2 files changed, 8 insertions(+), 21 deletions(-)

diff --git a/lib/matplotlib/__init__.py b/lib/matplotlib/__init__.py
index 18fa9906b4f6..2dbacc9d989e 100644
--- a/lib/matplotlib/__init__.py
+++ b/lib/matplotlib/__init__.py
@@ -135,7 +135,7 @@
 
 import atexit
 from collections import namedtuple, ChainMap
-from collections.abc import MutableMapping, Mapping
+from collections.abc import MutableMapping, Mapping, KeysView, ValuesView, ItemsView
 import contextlib
 import functools
 import importlib
@@ -850,8 +850,13 @@ def __contains__(self, key):
 
     def __iter__(self):
         """Yield from sorted list of keys"""
+        keys = (
+            ".".join((space, key))
+            for space, mapping in self._namespace_maps.items()
+            for key in mapping.keys()
+        )
         with _api.suppress_matplotlib_deprecation_warning():
-            yield from sorted(self.keys())
+            yield from sorted(keys)
 
     def __len__(self):
         return sum(len(mapping) for mapping in self._namespace_maps)
@@ -868,22 +873,6 @@ def __repr__(self):
     def __str__(self):
         return '\n'.join(map('{0[0]}: {0[1]}'.format, sorted(self.items())))
 
-    def keys(self):
-        keys = (
-            ".".join((space, key))
-            for space, mapping in self._namespace_maps.items()
-            for key in mapping.keys()
-        )
-        return keys
-
-    def values(self):
-        for key in self.keys():
-            yield self[key]
-
-    def items(self):
-        for key, value in zip(self.keys(), self.values()):
-            yield key, value
-
     def pop(self, key):
         keys, depth = self._split_key(key)
         if depth == 1:
diff --git a/lib/matplotlib/__init__.pyi b/lib/matplotlib/__init__.pyi
index 1bbef561b9e4..fc87f31afc7f 100644
--- a/lib/matplotlib/__init__.pyi
+++ b/lib/matplotlib/__init__.pyi
@@ -70,7 +70,7 @@ class RcParams(MutableMapping):
     namespaces: tuple
     single_key_set: set
     def __init__(self, *args, **kwargs) -> None: ...
-    def _split_key(self, key: str, sep: str = ".") -> tuple[list, int]: ...
+    def _split_key(key: str, sep: str = ...) -> tuple[list, int]: ...
     def _set(self, key: str, val: Any) -> None: ...
     def _get(self, key: str) -> Any: ...
     def __setitem__(self, key: str, val: Any) -> None: ...
@@ -78,8 +78,6 @@ class RcParams(MutableMapping):
     def __delitem__(self, key: str) -> None: ...
     def __iter__(self) -> Generator[str, None, None]: ...
     def __len__(self) -> int: ...
-    def keys(self) -> Generator[str, None, None]: ...
-    def values(self) -> Generator[Any, None, None]: ...
     def find_all(self, pattern: str) -> RcParams: ...
     def copy(self) -> RcParams: ...
 

From 4f9d8b6f5f782d5f152bf6769b6fadcd5bac531c Mon Sep 17 00:00:00 2001
From: Chahak Mehta <chahakmehta013@gmail.com>
Date: Tue, 25 Apr 2023 21:13:20 -0500
Subject: [PATCH 11/22] Add type spec for MutableMapping

---
 lib/matplotlib/__init__.pyi | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/matplotlib/__init__.pyi b/lib/matplotlib/__init__.pyi
index fc87f31afc7f..b5966b3be344 100644
--- a/lib/matplotlib/__init__.pyi
+++ b/lib/matplotlib/__init__.pyi
@@ -65,7 +65,7 @@ def get_cachedir() -> str: ...
 def get_data_path() -> str: ...
 def matplotlib_fname() -> str: ...
 
-class RcParams(MutableMapping):
+class RcParams(MutableMapping[str, Any]):
     validate: dict[str, Callable]
     namespaces: tuple
     single_key_set: set

From 54a1a113616ebe3b9d2b1a80bb7750270ef3c34d Mon Sep 17 00:00:00 2001
From: Chahak Mehta <chahakmehta013@gmail.com>
Date: Wed, 26 Apr 2023 15:10:57 -0500
Subject: [PATCH 12/22] Remove `default.` usage outside the RcParams class

This is to make the interface such that the code other than RcParams
doesn't have to deal with the `deafult.*` namespace anywhere. This also
changes the keys returned by `.keys()` to not have the `default.*` in
the key name.
---
 lib/matplotlib/__init__.py            | 35 ++++++++++++---------------
 lib/matplotlib/pyplot.py              | 12 ++++-----
 lib/matplotlib/rcsetup.py             | 10 ++++----
 lib/matplotlib/style/core.py          |  6 ++---
 lib/matplotlib/tests/test_rcparams.py |  2 +-
 lib/matplotlib/tests/test_widgets.py  |  2 +-
 6 files changed, 32 insertions(+), 35 deletions(-)

diff --git a/lib/matplotlib/__init__.py b/lib/matplotlib/__init__.py
index 2dbacc9d989e..3be422ab3a3c 100644
--- a/lib/matplotlib/__init__.py
+++ b/lib/matplotlib/__init__.py
@@ -781,12 +781,12 @@ def __setitem__(self, key, val):
                 return
             elif key == 'backend' or key == "default.backend":
                 if val is rcsetup._auto_backend_sentinel:
-                    if 'backend' in self:
+                    if 'backend' in self or 'default.backend' in self:
                         return
-            if key in self.single_key_set:
-                key = f"default.{key}"
             try:
                 cval = self.validate[key](val)
+                if key in self.single_key_set:
+                    key = f"default.{key}"
             except ValueError as ve:
                 raise ValueError(f"Key {key}: {ve}") from None
             self._set(key, cval)
@@ -851,7 +851,7 @@ def __contains__(self, key):
     def __iter__(self):
         """Yield from sorted list of keys"""
         keys = (
-            ".".join((space, key))
+            ".".join((space, key)) if space != 'default' else key
             for space, mapping in self._namespace_maps.items()
             for key in mapping.keys()
         )
@@ -1023,8 +1023,6 @@ def _rc_params_in_file(fname, transform=lambda x: x, fail_on_error=False):
     config = RcParams()
 
     for key, (val, line, line_no) in rc_temp.items():
-        if key in config.single_key_set:
-            key = f"default.{key}"
         if key in rcsetup._validators:
             if fail_on_error:
                 config[key] = val  # try to convert to proper type or raise
@@ -1101,23 +1099,22 @@ def rc_params_from_file(fname, fail_on_error=False, use_default_template=True):
 # in that case.  However, packagers can set a different default backend
 # (resulting in a normal `#backend: foo` line) in which case we should *not*
 # fill in _auto_backend_sentinel.
-rcParamsDefault.setdefault("default.backend", rcsetup._auto_backend_sentinel)
-params_dict = RcParams()
-params_dict.update(rcParamsDefault.items())
-params_dict.update(_rc_params_in_file(matplotlib_fname()))
-rcParamsOrig = params_dict.copy()
+rcParamsDefault.setdefault("backend", rcsetup._auto_backend_sentinel)
+rcParams = RcParams()
+rcParams.update(rcParamsDefault.items())
+rcParams.update(_rc_params_in_file(matplotlib_fname()))
+rcParamsOrig = rcParams.copy()
 with _api.suppress_matplotlib_deprecation_warning():
     # This also checks that all rcParams are indeed listed in the template.
     # Assigning to rcsetup.defaultParams is left only for backcompat.
     defaultParams = rcsetup.defaultParams = {
         # We want to resolve deprecated rcParams, but not backend...
-        key: [(rcsetup._auto_backend_sentinel if key == "default.backend" else
+        key: [(rcsetup._auto_backend_sentinel if key == "backend" else
                rcParamsDefault[key]),
               validator]
         for key, validator in rcsetup._validators.items()}
-if params_dict['axes.formatter.use_locale']:
+if rcParams['axes.formatter.use_locale']:
     locale.setlocale(locale.LC_ALL, '')
-rcParams = RcParams(params_dict)
 
 
 def rc(group, **kwargs):
@@ -1393,14 +1390,14 @@ def use(backend, *, force=True):
         # value which will be respected when the user finally imports
         # pyplot
         else:
-            rcParams['default.backend'] = backend
+            rcParams['backend'] = backend
     # if the user has asked for a given backend, do not helpfully
     # fallback
-    rcParams['default.backend_fallback'] = False
+    rcParams['backend_fallback'] = False
 
 
 if os.environ.get('MPLBACKEND'):
-    rcParams['default.backend'] = os.environ.get('MPLBACKEND')
+    rcParams['backend'] = os.environ.get('MPLBACKEND')
 
 
 def get_backend():
@@ -1418,7 +1415,7 @@ def interactive(b):
     """
     Set whether to redraw after every plotting command (e.g. `.pyplot.xlabel`).
     """
-    rcParams['default.interactive'] = b
+    rcParams['interactive'] = b
 
 
 def is_interactive():
@@ -1430,7 +1427,7 @@ def is_interactive():
         This function is only intended for use in backends. End users should
         use `.pyplot.isinteractive` instead.
     """
-    return rcParams['default.interactive']
+    return rcParams['interactive']
 
 
 def _val_or_rc(val, rc_name):
diff --git a/lib/matplotlib/pyplot.py b/lib/matplotlib/pyplot.py
index a2b5190fff67..945f12cd7137 100644
--- a/lib/matplotlib/pyplot.py
+++ b/lib/matplotlib/pyplot.py
@@ -327,16 +327,16 @@ def switch_backend(newbackend: str) -> None:
             except ImportError:
                 continue
             else:
-                rcParamsOrig['default.backend'] = candidate
+                rcParamsOrig['backend'] = candidate
                 return
         else:
             # Switching to Agg should always succeed; if it doesn't, let the
             # exception propagate out.
             switch_backend("agg")
-            rcParamsOrig["default.backend"] = "agg"
+            rcParamsOrig["backend"] = "agg"
             return
     # have to escape the switch on access logic
-    old_backend = rcParams['default.backend']
+    old_backend = rcParams._get('backend')
 
     module = importlib.import_module(cbook._backend_module_name(newbackend))
     canvas_class = module.FigureCanvas
@@ -413,7 +413,7 @@ def draw_if_interactive() -> None:
     _log.debug("Loaded backend %s version %s.",
                newbackend, backend_mod.backend_version)
 
-    rcParams['default.backend'] = rcParamsDefault['default.backend'] = newbackend
+    rcParams['backend'] = rcParamsDefault['backend'] = newbackend
     _backend_mod = backend_mod
     for func_name in ["new_figure_manager", "draw_if_interactive", "show"]:
         globals()[func_name].__signature__ = inspect.signature(
@@ -2472,11 +2472,11 @@ def polar(*args, **kwargs) -> list[Line2D]:
 # If rcParams['backend_fallback'] is true, and an interactive backend is
 # requested, ignore rcParams['backend'] and force selection of a backend that
 # is compatible with the current running interactive framework.
-if (rcParams["default.backend_fallback"]
+if (rcParams["backend_fallback"]
         and rcParams._get_backend_or_none() in (  # type: ignore
             set(rcsetup.interactive_bk) - {'WebAgg', 'nbAgg'})
         and cbook._get_running_interactive_framework()):  # type: ignore
-    rcParams._set("default.backend", rcsetup._auto_backend_sentinel)  # type: ignore
+    rcParams._set("backend", rcsetup._auto_backend_sentinel)  # type: ignore
 
 # fmt: on
 
diff --git a/lib/matplotlib/rcsetup.py b/lib/matplotlib/rcsetup.py
index bee0204a46b9..38d4606024d3 100644
--- a/lib/matplotlib/rcsetup.py
+++ b/lib/matplotlib/rcsetup.py
@@ -892,12 +892,12 @@ def _convert_validator_spec(key, conv):
 # The rcParams defaults are defined in lib/matplotlib/mpl-data/matplotlibrc, which
 # gets copied to matplotlib/mpl-data/matplotlibrc by the setup script.
 _validators = {
-    "default.backend":           validate_backend,
-    "default.backend_fallback":  validate_bool,
+    "backend":           validate_backend,
+    "backend_fallback":  validate_bool,
     "figure.hooks":      validate_stringlist,
-    "default.toolbar":           _validate_toolbar,
-    "default.interactive":       validate_bool,
-    "default.timezone":          validate_string,
+    "toolbar":           _validate_toolbar,
+    "interactive":       validate_bool,
+    "timezone":          validate_string,
 
     "webagg.port":            validate_int,
     "webagg.address":         validate_string,
diff --git a/lib/matplotlib/style/core.py b/lib/matplotlib/style/core.py
index 57ea5fa5df1d..7e9008c56165 100644
--- a/lib/matplotlib/style/core.py
+++ b/lib/matplotlib/style/core.py
@@ -39,9 +39,9 @@
 STYLE_EXTENSION = 'mplstyle'
 # A list of rcParams that should not be applied from styles
 STYLE_BLACKLIST = {
-    'default.interactive', 'default.backend', 'webagg.port', 'webagg.address',
-    'webagg.port_retries', 'webagg.open_in_browser', 'default.backend_fallback',
-    'default.toolbar', 'default.timezone', 'figure.max_open_warning',
+    'interactive', 'backend', 'webagg.port', 'webagg.address',
+    'webagg.port_retries', 'webagg.open_in_browser', 'backend_fallback',
+    'toolbar', 'timezone', 'figure.max_open_warning',
     'figure.raise_window', 'savefig.directory', 'tk.window_focus',
     'docstring.hardcopy', 'date.epoch'}
 
diff --git a/lib/matplotlib/tests/test_rcparams.py b/lib/matplotlib/tests/test_rcparams.py
index 609e80bb4138..65cd823f13a9 100644
--- a/lib/matplotlib/tests/test_rcparams.py
+++ b/lib/matplotlib/tests/test_rcparams.py
@@ -199,7 +199,7 @@ def test_axes_titlecolor_rcparams():
 
 def test_Issue_1713(tmpdir):
     rcpath = Path(tmpdir) / 'test_rcparams.rc'
-    rcpath.write_text('default.timezone: UTC', encoding='utf-8')
+    rcpath.write_text('timezone: UTC', encoding='utf-8')
     with mock.patch('locale.getpreferredencoding', return_value='UTF-32-BE'):
         rc = mpl.rc_params_from_file(rcpath, True, False)
     assert rc.get('timezone') == 'UTC'
diff --git a/lib/matplotlib/tests/test_widgets.py b/lib/matplotlib/tests/test_widgets.py
index b96c5693f6a2..de17bb79bd4b 100644
--- a/lib/matplotlib/tests/test_widgets.py
+++ b/lib/matplotlib/tests/test_widgets.py
@@ -1029,7 +1029,7 @@ def test_CheckButtons(ax):
 @pytest.mark.parametrize("toolbar", ["none", "toolbar2", "toolmanager"])
 def test_TextBox(ax, toolbar):
     # Avoid "toolmanager is provisional" warning.
-    plt.rcParams._set("default.toolbar", toolbar)
+    plt.rcParams._set("toolbar", toolbar)
 
     submit_event = mock.Mock(spec=noop, return_value=None)
     text_change_event = mock.Mock(spec=noop, return_value=None)

From c101fec43ab1da11c0ff4c2992dbe5463d0b318f Mon Sep 17 00:00:00 2001
From: Chahak Mehta <chahakmehta013@gmail.com>
Date: Wed, 26 Apr 2023 15:46:13 -0500
Subject: [PATCH 13/22] Update _split_key stub to staticmethod

---
 lib/matplotlib/__init__.pyi | 1 +
 1 file changed, 1 insertion(+)

diff --git a/lib/matplotlib/__init__.pyi b/lib/matplotlib/__init__.pyi
index b5966b3be344..8691ef420166 100644
--- a/lib/matplotlib/__init__.pyi
+++ b/lib/matplotlib/__init__.pyi
@@ -70,6 +70,7 @@ class RcParams(MutableMapping[str, Any]):
     namespaces: tuple
     single_key_set: set
     def __init__(self, *args, **kwargs) -> None: ...
+    @staticmethod
     def _split_key(key: str, sep: str = ...) -> tuple[list, int]: ...
     def _set(self, key: str, val: Any) -> None: ...
     def _get(self, key: str) -> Any: ...

From 67735b09bc22949b6b831db23da461d1d443e31f Mon Sep 17 00:00:00 2001
From: Chahak Mehta <chahakmehta013@gmail.com>
Date: Wed, 10 May 2023 21:57:43 -0500
Subject: [PATCH 14/22] Add way to access default params

---
 lib/matplotlib/__init__.py            | 52 ++++++++++++++++++++++-----
 lib/matplotlib/tests/test_rcparams.py |  5 +++
 2 files changed, 49 insertions(+), 8 deletions(-)

diff --git a/lib/matplotlib/__init__.py b/lib/matplotlib/__init__.py
index 3be422ab3a3c..d67d34f968f0 100644
--- a/lib/matplotlib/__init__.py
+++ b/lib/matplotlib/__init__.py
@@ -681,10 +681,7 @@ class RcParams(MutableMapping):
     def __init__(self, *args, **kwargs):
         self._namespace_maps = {name: ChainMap({}) for name in self.namespaces}
         self.update(*args, **kwargs)
-        self._namespace_maps = {
-            name: mapping.new_child()
-            for name, mapping in self._namespace_maps.items()
-        }
+        self._new_child()
 
     @staticmethod
     @functools.lru_cache
@@ -692,6 +689,14 @@ def _split_key(key, sep="."):
         keys = key.split(sep, maxsplit=1)
         return keys, len(keys)
 
+    def _new_child(self):
+        for space in self._namespace_maps.keys():
+            self._namespace_maps[space] = self._namespace_maps[space].new_child()
+
+    def _parents(self):
+        for space in self._namespace_maps.keys():
+            self._namespace_maps[space] = self._namespace_maps[space].parents
+
     def _set(self, key, val):
         """
         Directly write data bypassing deprecation and validation logic.
@@ -818,6 +823,36 @@ def __getitem__(self, key):
 
         return self._get(key)
 
+    def _get_default(self, key):
+        keys, depth = self._split_key(key)
+        if depth == 1:
+            if key in self.single_key_set:
+                return self._namespace_maps["default"].get(key)
+            # Uncomment the following line and remove the raise statement
+            # to enable getting namespace parameters.
+            # return self._namespace_maps[key]
+            else:
+                raise KeyError(
+                    f"{key} is not a valid rc parameter (see rcParams.keys() for "
+                    f"a list of valid parameters)")
+        elif depth == 2:
+            return self._namespace_maps[keys[0]].maps[-1].get(keys[1])
+
+    def getdefault(self, key):
+        if key in _deprecated_map:
+            version, alt_key, alt_val, inverse_alt = _deprecated_map[key]
+            _api.warn_deprecated(
+                version, name=key, obj_type="rcparam", alternative=alt_key)
+            return inverse_alt(self._get(alt_key))
+
+        elif key in _deprecated_ignore_map:
+            version, alt_key = _deprecated_ignore_map[key]
+            _api.warn_deprecated(
+                version, name=key, obj_type="rcparam", alternative=alt_key)
+            return self._get_default(alt_key) if alt_key else None
+
+        return self._get_default(key)
+
     def _get_backend_or_none(self):
         """Get the requested backend, if any, without triggering resolution."""
         backend = self._get("backend")
@@ -1021,6 +1056,7 @@ def _rc_params_in_file(fname, transform=lambda x: x, fail_on_error=False):
             raise
 
     config = RcParams()
+    config._parents()
 
     for key, (val, line, line_no) in rc_temp.items():
         if key in rcsetup._validators:
@@ -1049,6 +1085,7 @@ def _rc_params_in_file(fname, transform=lambda x: x, fail_on_error=False):
 or from the matplotlib source distribution""",
                          dict(key=key, fname=fname, line_no=line_no,
                               line=line.rstrip('\n'), version=version))
+    config._new_child()
     return config
 
 
@@ -1101,6 +1138,7 @@ def rc_params_from_file(fname, fail_on_error=False, use_default_template=True):
 # fill in _auto_backend_sentinel.
 rcParamsDefault.setdefault("backend", rcsetup._auto_backend_sentinel)
 rcParams = RcParams()
+rcParams._parents()
 rcParams.update(rcParamsDefault.items())
 rcParams.update(_rc_params_in_file(matplotlib_fname()))
 rcParamsOrig = rcParams.copy()
@@ -1115,6 +1153,7 @@ def rc_params_from_file(fname, fail_on_error=False, use_default_template=True):
         for key, validator in rcsetup._validators.items()}
 if rcParams['axes.formatter.use_locale']:
     locale.setlocale(locale.LC_ALL, '')
+rcParams._new_child()
 
 
 def rc(group, **kwargs):
@@ -1318,10 +1357,7 @@ def rc_context(rc=None, fname=None):
     finally:
         # Revert to the original rcs.
         backend = rcParams["backend"]
-        for space in rcParams._namespace_maps.keys():
-            rcParams._namespace_maps[space] = rcParams._namespace_maps[
-                space
-            ].parents
+        rcParams._parents()
         rcParams["backend"] = backend
 
 
diff --git a/lib/matplotlib/tests/test_rcparams.py b/lib/matplotlib/tests/test_rcparams.py
index 65cd823f13a9..a120e08413f2 100644
--- a/lib/matplotlib/tests/test_rcparams.py
+++ b/lib/matplotlib/tests/test_rcparams.py
@@ -652,3 +652,8 @@ def test_rcparams_path_sketch_from_file(tmpdir, value):
     rc_path.write(f"path.sketch: {value}")
     with mpl.rc_context(fname=rc_path):
         assert mpl.rcParams["path.sketch"] == (1, 2, 3)
+
+
+def test_rcparams_getdefault():
+    with mpl.rc_context({"image.lut": 128}):
+        assert mpl.rcParams.getdefault("image.lut") == 256

From 7e4022ada95a1e68c6451bf4d666574f7e9c0a66 Mon Sep 17 00:00:00 2001
From: Chahak Mehta <chahakmehta013@gmail.com>
Date: Wed, 10 May 2023 23:53:51 -0500
Subject: [PATCH 15/22] Remove `rcParamsDefault`

---
 lib/matplotlib/__init__.py             | 28 ++++++++++++++++----------
 lib/matplotlib/pyplot.py               |  5 +++--
 lib/matplotlib/style/core.py           |  4 ++--
 lib/matplotlib/tests/test_offsetbox.py |  5 +++++
 lib/matplotlib/tests/test_rcparams.py  |  7 +++++++
 5 files changed, 34 insertions(+), 15 deletions(-)

diff --git a/lib/matplotlib/__init__.py b/lib/matplotlib/__init__.py
index d67d34f968f0..69344a420376 100644
--- a/lib/matplotlib/__init__.py
+++ b/lib/matplotlib/__init__.py
@@ -853,6 +853,12 @@ def getdefault(self, key):
 
         return self._get_default(key)
 
+    def getdefaults(self):
+        """Return default values set during initialization."""
+        defaults = self.copy()
+        defaults.clear()
+        return defaults
+
     def _get_backend_or_none(self):
         """Get the requested backend, if any, without triggering resolution."""
         backend = self._get("backend")
@@ -1110,7 +1116,7 @@ def rc_params_from_file(fname, fail_on_error=False, use_default_template=True):
         return config_from_file
 
     with _api.suppress_matplotlib_deprecation_warning():
-        config = RcParams({**rcParamsDefault, **config_from_file})
+        config = RcParams({**rcParams.getdefaults(), **config_from_file})
 
     if "".join(config['text.latex.preamble']):
         _log.info("""
@@ -1125,21 +1131,22 @@ def rc_params_from_file(fname, fail_on_error=False, use_default_template=True):
     return config
 
 
-rcParamsDefault = _rc_params_in_file(
+rcParams = _rc_params_in_file(
     cbook._get_data_path("matplotlibrc"),
     # Strip leading comment.
     transform=lambda line: line[1:] if line.startswith("#") else line,
     fail_on_error=True)
-rcParamsDefault.update(rcsetup._hardcoded_defaults)
+for key in rcsetup._hardcoded_defaults:
+    space, subkey = key.split(".")
+    if not rcParams._namespace_maps[space]:
+        rcParams._namespace_maps[space] = ChainMap({})
+rcParams.update(rcsetup._hardcoded_defaults)
 # Normally, the default matplotlibrc file contains *no* entry for backend (the
 # corresponding line starts with ##, not #; we fill on _auto_backend_sentinel
 # in that case.  However, packagers can set a different default backend
 # (resulting in a normal `#backend: foo` line) in which case we should *not*
 # fill in _auto_backend_sentinel.
-rcParamsDefault.setdefault("backend", rcsetup._auto_backend_sentinel)
-rcParams = RcParams()
-rcParams._parents()
-rcParams.update(rcParamsDefault.items())
+rcParams.setdefault("backend", rcsetup._auto_backend_sentinel)
 rcParams.update(_rc_params_in_file(matplotlib_fname()))
 rcParamsOrig = rcParams.copy()
 with _api.suppress_matplotlib_deprecation_warning():
@@ -1148,12 +1155,11 @@ def rc_params_from_file(fname, fail_on_error=False, use_default_template=True):
     defaultParams = rcsetup.defaultParams = {
         # We want to resolve deprecated rcParams, but not backend...
         key: [(rcsetup._auto_backend_sentinel if key == "backend" else
-               rcParamsDefault[key]),
+               rcParams.getdefault(key)),
               validator]
         for key, validator in rcsetup._validators.items()}
 if rcParams['axes.formatter.use_locale']:
     locale.setlocale(locale.LC_ALL, '')
-rcParams._new_child()
 
 
 def rc(group, **kwargs):
@@ -1253,8 +1259,8 @@ def rcdefaults():
     with _api.suppress_matplotlib_deprecation_warning():
         from .style.core import STYLE_BLACKLIST
         rcParams.clear()
-        rcParams.update({k: v for k, v in rcParamsDefault.items()
-                         if k not in STYLE_BLACKLIST})
+        # rcParams.update({k: v for k, v in rcParams.items()
+        #                  if k not in STYLE_BLACKLIST})
 
 
 def rc_file_defaults():
diff --git a/lib/matplotlib/pyplot.py b/lib/matplotlib/pyplot.py
index 945f12cd7137..8c7b6a873882 100644
--- a/lib/matplotlib/pyplot.py
+++ b/lib/matplotlib/pyplot.py
@@ -65,7 +65,8 @@
     FigureCanvasBase, FigureManagerBase, MouseButton)
 from matplotlib.figure import Figure, FigureBase, figaspect
 from matplotlib.gridspec import GridSpec, SubplotSpec
-from matplotlib import rcsetup, rcParamsDefault, rcParamsOrig
+from matplotlib import rcParams, get_backend, rcParamsOrig
+from matplotlib.rcsetup import interactive_bk as _interactive_bk
 from matplotlib.artist import Artist
 from matplotlib.axes import Axes, Subplot  # type: ignore
 from matplotlib.projections import PolarAxes  # type: ignore
@@ -413,7 +414,7 @@ def draw_if_interactive() -> None:
     _log.debug("Loaded backend %s version %s.",
                newbackend, backend_mod.backend_version)
 
-    rcParams['backend'] = rcParamsDefault['backend'] = newbackend
+    rcParams['backend'] = newbackend
     _backend_mod = backend_mod
     for func_name in ["new_figure_manager", "draw_if_interactive", "show"]:
         globals()[func_name].__signature__ = inspect.signature(
diff --git a/lib/matplotlib/style/core.py b/lib/matplotlib/style/core.py
index 7e9008c56165..392360920f92 100644
--- a/lib/matplotlib/style/core.py
+++ b/lib/matplotlib/style/core.py
@@ -26,7 +26,7 @@
     import importlib_resources
 
 import matplotlib as mpl
-from matplotlib import _api, _docstring, _rc_params_in_file, rcParamsDefault
+from matplotlib import _api, _docstring, _rc_params_in_file
 
 _log = logging.getLogger(__name__)
 
@@ -114,7 +114,7 @@ def use(style):
                 # rcParamsDefault, no need to reemit them here.
                 with _api.suppress_matplotlib_deprecation_warning():
                     # don't trigger RcParams.__getitem__('backend')
-                    style = {k: rcParamsDefault[k] for k in rcParamsDefault
+                    style = {k: mpl.rcParams.getdefault(k) for k in mpl.rcParams
                              if k not in STYLE_BLACKLIST}
             elif style in library:
                 style = library[style]
diff --git a/lib/matplotlib/tests/test_offsetbox.py b/lib/matplotlib/tests/test_offsetbox.py
index 49b55e4c9326..edf17542fb17 100644
--- a/lib/matplotlib/tests/test_offsetbox.py
+++ b/lib/matplotlib/tests/test_offsetbox.py
@@ -257,9 +257,14 @@ def test_anchoredtext_horizontal_alignment():
     ax.add_artist(text2)
 
 
+<<<<<<< HEAD
 @pytest.mark.parametrize("extent_kind", ["window_extent", "tightbbox"])
 def test_annotationbbox_extents(extent_kind):
     plt.rcParams.update(plt.rcParamsDefault)
+=======
+def test_annotationbbox_extents():
+    plt.rcParams.clear()
+>>>>>>> 57d742c95e (Remove `rcParamsDefault`)
     fig, ax = plt.subplots(figsize=(4, 3), dpi=100)
 
     ax.axis([0, 1, 0, 1])
diff --git a/lib/matplotlib/tests/test_rcparams.py b/lib/matplotlib/tests/test_rcparams.py
index a120e08413f2..50df368ec227 100644
--- a/lib/matplotlib/tests/test_rcparams.py
+++ b/lib/matplotlib/tests/test_rcparams.py
@@ -657,3 +657,10 @@ def test_rcparams_path_sketch_from_file(tmpdir, value):
 def test_rcparams_getdefault():
     with mpl.rc_context({"image.lut": 128}):
         assert mpl.rcParams.getdefault("image.lut") == 256
+
+
+def test_rcparams_getdefaults():
+    mpl.rc("image", lut=128)
+    defaults = mpl.rcParams.getdefaults()
+    mpl.rcParams.clear()
+    assert defaults == mpl.rcParams

From c23cb2914beba5fb945c22b05b0b80daaaaab90c Mon Sep 17 00:00:00 2001
From: Chahak Mehta <chahakmehta013@gmail.com>
Date: Thu, 11 May 2023 15:18:24 -0500
Subject: [PATCH 16/22] Update `rcdefaults` to use `style.core.use()`

---
 lib/matplotlib/__init__.py            | 11 ++++-------
 lib/matplotlib/style/core.py          |  1 +
 lib/matplotlib/tests/test_rcparams.py | 14 ++++++++++++++
 3 files changed, 19 insertions(+), 7 deletions(-)

diff --git a/lib/matplotlib/__init__.py b/lib/matplotlib/__init__.py
index 69344a420376..8db49cd9fe4f 100644
--- a/lib/matplotlib/__init__.py
+++ b/lib/matplotlib/__init__.py
@@ -1254,13 +1254,10 @@ def rcdefaults():
         Use a specific style file.  Call ``style.use('default')`` to restore
         the default style.
     """
-    # Deprecation warnings were already handled when creating rcParamsDefault,
-    # no need to reemit them here.
-    with _api.suppress_matplotlib_deprecation_warning():
-        from .style.core import STYLE_BLACKLIST
-        rcParams.clear()
-        # rcParams.update({k: v for k, v in rcParams.items()
-        #                  if k not in STYLE_BLACKLIST})
+    # # Deprecation warnings were already handled when creating rcParamsDefault,
+    # # no need to reemit them here.
+    from .style import core
+    core.use('default')
 
 
 def rc_file_defaults():
diff --git a/lib/matplotlib/style/core.py b/lib/matplotlib/style/core.py
index 392360920f92..6b2e6467d4a3 100644
--- a/lib/matplotlib/style/core.py
+++ b/lib/matplotlib/style/core.py
@@ -149,6 +149,7 @@ def use(style):
             else:
                 filtered[k] = style[k]
         mpl.rcParams.update(filtered)
+    mpl.rcParams._new_child()
 
 
 @contextlib.contextmanager
diff --git a/lib/matplotlib/tests/test_rcparams.py b/lib/matplotlib/tests/test_rcparams.py
index 50df368ec227..f1a53bfaef9e 100644
--- a/lib/matplotlib/tests/test_rcparams.py
+++ b/lib/matplotlib/tests/test_rcparams.py
@@ -664,3 +664,17 @@ def test_rcparams_getdefaults():
     defaults = mpl.rcParams.getdefaults()
     mpl.rcParams.clear()
     assert defaults == mpl.rcParams
+
+
+def test_rcdefaults():
+    # webagg.port is a style blacklisted key that shouldn't be
+    # updated when resetting rcParams to default values.
+    mpl.rcParams["webagg.port"] = 9000
+    # lines.linewidth is not a style blacklisted key and should be
+    # reset to the default value.
+    # breakpoint()
+    lw = mpl.rcParams.getdefault("lines.linewidth")
+    mpl.rcParams["lines.linewidth"] = lw + 1
+    mpl.rcdefaults()
+    assert mpl.rcParams["webagg.port"] == 9000
+    assert mpl.rcParams["lines.linewidth"] == lw

From 0374f464a1997a46c73057d801785262b87d7ecd Mon Sep 17 00:00:00 2001
From: Chahak Mehta <chahakmehta013@gmail.com>
Date: Thu, 11 May 2023 21:52:05 -0500
Subject: [PATCH 17/22] Make namespaces private and correct setdefault

---
 lib/matplotlib/__init__.py   | 40 +++++++++++++++++++++---------------
 lib/matplotlib/style/core.py |  1 -
 2 files changed, 23 insertions(+), 18 deletions(-)

diff --git a/lib/matplotlib/__init__.py b/lib/matplotlib/__init__.py
index 8db49cd9fe4f..43716ffa00b0 100644
--- a/lib/matplotlib/__init__.py
+++ b/lib/matplotlib/__init__.py
@@ -667,19 +667,19 @@ class RcParams(MutableMapping):
     :ref:`customizing-with-matplotlibrc-files`
     """
     validate = rcsetup._validators
-    namespaces = ("backends", "lines", "patches", "hatches", "boxplot", "font", "text",
-                  "latex", "axes", "date", "xtick", "ytick", "grid", "legend",
-                  "figure", "image", "contour", "errorbar", "hist", "scatter", "agg",
-                  "path", "savefig", "tk", "ps", "pdf", "svg", "pgf", "docstring",
-                  "keymap", "animation", "_internal", "webagg", "markers", "pcolor",
-                  "pcolormesh", "patch", "hatch", "mathtext", "polaraxes", "axes3d",
-                  "xaxis", "yaxis", "default")
+    _namespaces = ("backends", "lines", "patches", "hatches", "boxplot", "font", "text",
+                   "latex", "axes", "date", "xtick", "ytick", "grid", "legend",
+                   "figure", "image", "contour", "errorbar", "hist", "scatter", "agg",
+                   "path", "savefig", "tk", "ps", "pdf", "svg", "pgf", "docstring",
+                   "keymap", "animation", "_internal", "webagg", "markers", "pcolor",
+                   "pcolormesh", "patch", "hatch", "mathtext", "polaraxes", "axes3d",
+                   "xaxis", "yaxis", "default")
 
-    single_key_set = {"backend", "toolbar", "interactive",
-                      "timezone", "backend_fallback"}
+    _single_key_set = {"backend", "toolbar", "interactive",
+                       "timezone", "backend_fallback"}
 
     def __init__(self, *args, **kwargs):
-        self._namespace_maps = {name: ChainMap({}) for name in self.namespaces}
+        self._namespace_maps = {name: ChainMap({}) for name in self._namespaces}
         self.update(*args, **kwargs)
         self._new_child()
 
@@ -717,7 +717,7 @@ def _set(self, key, val):
         """
         keys, depth = self._split_key(key)
         if depth == 1:
-            if key in self.single_key_set:
+            if key in self._single_key_set:
                 self._namespace_maps["default"][key] = val
             # Uncomment the following line and remove the raise statement
             # to enable setting namespaces.
@@ -756,7 +756,7 @@ def _get(self, key):
         """
         keys, depth = self._split_key(key)
         if depth == 1:
-            if key in self.single_key_set:
+            if key in self._single_key_set:
                 return self._namespace_maps["default"].get(key)
             # Uncomment the following line and remove the raise statement
             # to enable getting namespace parameters.
@@ -790,7 +790,7 @@ def __setitem__(self, key, val):
                         return
             try:
                 cval = self.validate[key](val)
-                if key in self.single_key_set:
+                if key in self._single_key_set:
                     key = f"default.{key}"
             except ValueError as ve:
                 raise ValueError(f"Key {key}: {ve}") from None
@@ -826,7 +826,7 @@ def __getitem__(self, key):
     def _get_default(self, key):
         keys, depth = self._split_key(key)
         if depth == 1:
-            if key in self.single_key_set:
+            if key in self._single_key_set:
                 return self._namespace_maps["default"].get(key)
             # Uncomment the following line and remove the raise statement
             # to enable getting namespace parameters.
@@ -868,7 +868,7 @@ def __delitem__(self, key):
         keys, depth = self._split_key(key)
         try:
             if depth == 1:
-                if key in self.single_key_set:
+                if key in self._single_key_set:
                     del self._namespace_maps["default"][key]
                 else:
                     raise KeyError
@@ -882,7 +882,7 @@ def __delitem__(self, key):
     def __contains__(self, key):
         keys, depth = self._split_key(key)
         if depth == 1:
-            if key in self.single_key_set:
+            if key in self._single_key_set:
                 return key in self._namespace_maps["default"]
             else:
                 return False
@@ -917,7 +917,7 @@ def __str__(self):
     def pop(self, key):
         keys, depth = self._split_key(key)
         if depth == 1:
-            if key in self.single_key_set:
+            if key in self._single_key_set:
                 return self._namespace_mapping["default"][key]
             else:
                 raise KeyError(
@@ -935,6 +935,12 @@ def clear(self):
             self._namespace_maps[namespace].clear()
 
     def setdefault(self, key, default=None):
+        """Insert key with a value of default if key is not in the dictionary.
+
+        Return the value for key if key is in the dictionary, else default.
+        """
+        if key in self:
+            return self[key]
         self[key] = default
         return default
 
diff --git a/lib/matplotlib/style/core.py b/lib/matplotlib/style/core.py
index 6b2e6467d4a3..392360920f92 100644
--- a/lib/matplotlib/style/core.py
+++ b/lib/matplotlib/style/core.py
@@ -149,7 +149,6 @@ def use(style):
             else:
                 filtered[k] = style[k]
         mpl.rcParams.update(filtered)
-    mpl.rcParams._new_child()
 
 
 @contextlib.contextmanager

From dd99c1d5687fae6f6d5adb2d71956135bea29e96 Mon Sep 17 00:00:00 2001
From: Chahak Mehta <chahakmehta013@gmail.com>
Date: Sun, 28 May 2023 14:03:35 -0700
Subject: [PATCH 18/22] Remove namespaces and keep chainmap for settings.

As per @timhoffm's suggestion, decreasing scope of this PR to first just
remove the dict inheritance and add a ChainMap to maintain settings.
This is a fairly straightforward change and doesn't change the
interface. Furthermore, the keys are still dotted and don't support
namespacing as defining namespaces might take a little more discussion.
---
 lib/matplotlib/__init__.py            | 143 +++++---------------------
 lib/matplotlib/style/core.py          |   2 +-
 lib/matplotlib/tests/test_rcparams.py |  12 ++-
 3 files changed, 36 insertions(+), 121 deletions(-)

diff --git a/lib/matplotlib/__init__.py b/lib/matplotlib/__init__.py
index 43716ffa00b0..b850a69d8d3a 100644
--- a/lib/matplotlib/__init__.py
+++ b/lib/matplotlib/__init__.py
@@ -667,35 +667,11 @@ class RcParams(MutableMapping):
     :ref:`customizing-with-matplotlibrc-files`
     """
     validate = rcsetup._validators
-    _namespaces = ("backends", "lines", "patches", "hatches", "boxplot", "font", "text",
-                   "latex", "axes", "date", "xtick", "ytick", "grid", "legend",
-                   "figure", "image", "contour", "errorbar", "hist", "scatter", "agg",
-                   "path", "savefig", "tk", "ps", "pdf", "svg", "pgf", "docstring",
-                   "keymap", "animation", "_internal", "webagg", "markers", "pcolor",
-                   "pcolormesh", "patch", "hatch", "mathtext", "polaraxes", "axes3d",
-                   "xaxis", "yaxis", "default")
-
-    _single_key_set = {"backend", "toolbar", "interactive",
-                       "timezone", "backend_fallback"}
 
     def __init__(self, *args, **kwargs):
-        self._namespace_maps = {name: ChainMap({}) for name in self._namespaces}
+        self._rcvalues = ChainMap({})
         self.update(*args, **kwargs)
-        self._new_child()
-
-    @staticmethod
-    @functools.lru_cache
-    def _split_key(key, sep="."):
-        keys = key.split(sep, maxsplit=1)
-        return keys, len(keys)
-
-    def _new_child(self):
-        for space in self._namespace_maps.keys():
-            self._namespace_maps[space] = self._namespace_maps[space].new_child()
-
-    def _parents(self):
-        for space in self._namespace_maps.keys():
-            self._namespace_maps[space] = self._namespace_maps[space].parents
+        self._rcvalues.new_child()
 
     def _set(self, key, val):
         """
@@ -715,25 +691,7 @@ def _set(self, key, val):
 
         :meta public:
         """
-        keys, depth = self._split_key(key)
-        if depth == 1:
-            if key in self._single_key_set:
-                self._namespace_maps["default"][key] = val
-            # Uncomment the following line and remove the raise statement
-            # to enable setting namespaces.
-            # else:
-            #     if isinstance(val, dict):
-            #         self._namespace_maps[key] = ChainMap({}, val)
-            #     else:
-            #         raise ValueError(
-            #             f"{key} should be set using a dictionary but found "
-            #             f"{type(val)}")
-            else:
-                raise KeyError(
-                    f"{key} is not a valid rc parameter (see rcParams.keys() for "
-                    f"a list of valid parameters)")
-        elif depth == 2:
-            self._namespace_maps[keys[0]][keys[1]] = val
+        self._rcvalues[key] = val
 
     def _get(self, key):
         """
@@ -754,19 +712,7 @@ def _get(self, key):
 
         :meta public:
         """
-        keys, depth = self._split_key(key)
-        if depth == 1:
-            if key in self._single_key_set:
-                return self._namespace_maps["default"].get(key)
-            # Uncomment the following line and remove the raise statement
-            # to enable getting namespace parameters.
-            # return self._namespace_maps[key]
-            else:
-                raise KeyError(
-                    f"{key} is not a valid rc parameter (see rcParams.keys() for "
-                    f"a list of valid parameters)")
-        elif depth == 2:
-            return self._namespace_maps[keys[0]].get(keys[1])
+        return self._rcvalues[key]
 
     def __setitem__(self, key, val):
         try:
@@ -790,8 +736,8 @@ def __setitem__(self, key, val):
                         return
             try:
                 cval = self.validate[key](val)
-                if key in self._single_key_set:
-                    key = f"default.{key}"
+                # if key in self._single_key_set:
+                #     key = f"default.{key}"
             except ValueError as ve:
                 raise ValueError(f"Key {key}: {ve}") from None
             self._set(key, cval)
@@ -824,21 +770,9 @@ def __getitem__(self, key):
         return self._get(key)
 
     def _get_default(self, key):
-        keys, depth = self._split_key(key)
-        if depth == 1:
-            if key in self._single_key_set:
-                return self._namespace_maps["default"].get(key)
-            # Uncomment the following line and remove the raise statement
-            # to enable getting namespace parameters.
-            # return self._namespace_maps[key]
-            else:
-                raise KeyError(
-                    f"{key} is not a valid rc parameter (see rcParams.keys() for "
-                    f"a list of valid parameters)")
-        elif depth == 2:
-            return self._namespace_maps[keys[0]].maps[-1].get(keys[1])
+        return self._rcvalues.maps[-1][key]
 
-    def getdefault(self, key):
+    def get_default(self, key):
         if key in _deprecated_map:
             version, alt_key, alt_val, inverse_alt = _deprecated_map[key]
             _api.warn_deprecated(
@@ -853,7 +787,7 @@ def getdefault(self, key):
 
         return self._get_default(key)
 
-    def getdefaults(self):
+    def get_defaults(self):
         """Return default values set during initialization."""
         defaults = self.copy()
         defaults.clear()
@@ -865,54 +799,35 @@ def _get_backend_or_none(self):
         return None if backend is rcsetup._auto_backend_sentinel else backend
 
     def __delitem__(self, key):
-        keys, depth = self._split_key(key)
         try:
-            if depth == 1:
-                if key in self._single_key_set:
-                    del self._namespace_maps["default"][key]
-                else:
-                    raise KeyError
-            elif depth == 2:
-                del self._namespace_maps[keys[0]][keys[1]]
+            del self._rcvalues[key]
         except KeyError as err:
             raise KeyError(
                 f"{key} is not a valid rc parameter (see rcParams.keys() for "
                 f"a list of valid parameters)") from err
 
     def __contains__(self, key):
-        keys, depth = self._split_key(key)
-        if depth == 1:
-            if key in self._single_key_set:
-                return key in self._namespace_maps["default"]
-            else:
-                return False
-        elif depth == 2:
-            return any(key in mapping for mapping in self._namespace_maps)
+        return key in self._rcvalues
 
     def __iter__(self):
         """Yield from sorted list of keys"""
-        keys = (
-            ".".join((space, key)) if space != 'default' else key
-            for space, mapping in self._namespace_maps.items()
-            for key in mapping.keys()
-        )
         with _api.suppress_matplotlib_deprecation_warning():
-            yield from sorted(keys)
+            yield from sorted(self._rcvalues.keys())
 
     def __len__(self):
-        return sum(len(mapping) for mapping in self._namespace_maps)
+        return len(self._rcvalues)
 
     def __repr__(self):
         class_name = self.__class__.__name__
         indent = len(class_name) + 1
         with _api.suppress_matplotlib_deprecation_warning():
-            repr_split = pprint.pformat(dict(self.items()), indent=1,
+            repr_split = pprint.pformat(dict(self._rcvalues.items()), indent=1,
                                         width=80 - indent).split('\n')
         repr_indented = ('\n' + ' ' * indent).join(repr_split)
         return f'{class_name}({repr_indented})'
 
     def __str__(self):
-        return '\n'.join(map('{0[0]}: {0[1]}'.format, sorted(self.items())))
+        return '\n'.join(map('{0[0]}: {0[1]}'.format, sorted(self._rcvalues.items())))
 
     def pop(self, key):
         keys, depth = self._split_key(key)
@@ -931,8 +846,7 @@ def popitem(self):
             "popitem is not implemented for RcParams.")
 
     def clear(self):
-        for namespace in self._namespace_maps:
-            self._namespace_maps[namespace].clear()
+        self._rcvalues.clear()
 
     def setdefault(self, key, default=None):
         """Insert key with a value of default if key is not in the dictionary.
@@ -1067,8 +981,7 @@ def _rc_params_in_file(fname, transform=lambda x: x, fail_on_error=False):
                          fname)
             raise
 
-    config = RcParams()
-    config._parents()
+    config = dict()
 
     for key, (val, line, line_no) in rc_temp.items():
         if key in rcsetup._validators:
@@ -1097,8 +1010,7 @@ def _rc_params_in_file(fname, transform=lambda x: x, fail_on_error=False):
 or from the matplotlib source distribution""",
                          dict(key=key, fname=fname, line_no=line_no,
                               line=line.rstrip('\n'), version=version))
-    config._new_child()
-    return config
+    return RcParams(config)
 
 
 def rc_params_from_file(fname, fail_on_error=False, use_default_template=True):
@@ -1122,7 +1034,7 @@ def rc_params_from_file(fname, fail_on_error=False, use_default_template=True):
         return config_from_file
 
     with _api.suppress_matplotlib_deprecation_warning():
-        config = RcParams({**rcParams.getdefaults(), **config_from_file})
+        config = RcParams({**rcParams.get_defaults(), **config_from_file})
 
     if "".join(config['text.latex.preamble']):
         _log.info("""
@@ -1142,10 +1054,10 @@ def rc_params_from_file(fname, fail_on_error=False, use_default_template=True):
     # Strip leading comment.
     transform=lambda line: line[1:] if line.startswith("#") else line,
     fail_on_error=True)
-for key in rcsetup._hardcoded_defaults:
-    space, subkey = key.split(".")
-    if not rcParams._namespace_maps[space]:
-        rcParams._namespace_maps[space] = ChainMap({})
+# for key in rcsetup._hardcoded_defaults:
+#     space, subkey = key.split(".")
+#     if not rcParams._namespace_maps[space]:
+#         rcParams._namespace_maps[space] = ChainMap({})
 rcParams.update(rcsetup._hardcoded_defaults)
 # Normally, the default matplotlibrc file contains *no* entry for backend (the
 # corresponding line starts with ##, not #; we fill on _auto_backend_sentinel
@@ -1161,7 +1073,7 @@ def rc_params_from_file(fname, fail_on_error=False, use_default_template=True):
     defaultParams = rcsetup.defaultParams = {
         # We want to resolve deprecated rcParams, but not backend...
         key: [(rcsetup._auto_backend_sentinel if key == "backend" else
-               rcParams.getdefault(key)),
+               rcParams.get_default(key)),
               validator]
         for key, validator in rcsetup._validators.items()}
 if rcParams['axes.formatter.use_locale']:
@@ -1354,10 +1266,7 @@ def rc_context(rc=None, fname=None):
 
     """
     try:
-        for space in rcParams._namespace_maps.keys():
-            rcParams._namespace_maps[space] = rcParams._namespace_maps[
-                space
-            ].new_child()
+        rcParams._rcvalues = rcParams._rcvalues.new_child()
         if fname:
             rc_file(fname)
         if rc:
@@ -1366,7 +1275,7 @@ def rc_context(rc=None, fname=None):
     finally:
         # Revert to the original rcs.
         backend = rcParams["backend"]
-        rcParams._parents()
+        rcParams._rcvalues = rcParams._rcvalues.parents
         rcParams["backend"] = backend
 
 
diff --git a/lib/matplotlib/style/core.py b/lib/matplotlib/style/core.py
index 392360920f92..57b3a60a0a54 100644
--- a/lib/matplotlib/style/core.py
+++ b/lib/matplotlib/style/core.py
@@ -114,7 +114,7 @@ def use(style):
                 # rcParamsDefault, no need to reemit them here.
                 with _api.suppress_matplotlib_deprecation_warning():
                     # don't trigger RcParams.__getitem__('backend')
-                    style = {k: mpl.rcParams.getdefault(k) for k in mpl.rcParams
+                    style = {k: mpl.rcParams.get_default(k) for k in mpl.rcParams
                              if k not in STYLE_BLACKLIST}
             elif style in library:
                 style = library[style]
diff --git a/lib/matplotlib/tests/test_rcparams.py b/lib/matplotlib/tests/test_rcparams.py
index f1a53bfaef9e..8defa1735edf 100644
--- a/lib/matplotlib/tests/test_rcparams.py
+++ b/lib/matplotlib/tests/test_rcparams.py
@@ -656,12 +656,12 @@ def test_rcparams_path_sketch_from_file(tmpdir, value):
 
 def test_rcparams_getdefault():
     with mpl.rc_context({"image.lut": 128}):
-        assert mpl.rcParams.getdefault("image.lut") == 256
+        assert mpl.rcParams.get_default("image.lut") == 256
 
 
 def test_rcparams_getdefaults():
     mpl.rc("image", lut=128)
-    defaults = mpl.rcParams.getdefaults()
+    defaults = mpl.rcParams.get_defaults()
     mpl.rcParams.clear()
     assert defaults == mpl.rcParams
 
@@ -673,8 +673,14 @@ def test_rcdefaults():
     # lines.linewidth is not a style blacklisted key and should be
     # reset to the default value.
     # breakpoint()
-    lw = mpl.rcParams.getdefault("lines.linewidth")
+    lw = mpl.rcParams.get_default("lines.linewidth")
     mpl.rcParams["lines.linewidth"] = lw + 1
     mpl.rcdefaults()
     assert mpl.rcParams["webagg.port"] == 9000
     assert mpl.rcParams["lines.linewidth"] == lw
+
+
+def test_rcparams_clear():
+    mpl.rcParams["image.lut"] = 128
+    mpl.rcParams.clear()
+    assert mpl.rcParams["image.lut"] == 256

From aa282d0d3a0dcacc2fc7a59569891cc50930e908 Mon Sep 17 00:00:00 2001
From: Chahak Mehta <chahakmehta013@gmail.com>
Date: Wed, 7 Jun 2023 21:10:55 -0700
Subject: [PATCH 19/22] Deprecate clear and other small updates for review

---
 lib/matplotlib/__init__.py            | 57 +++++++--------------------
 lib/matplotlib/tests/test_rcparams.py | 12 ++++--
 2 files changed, 23 insertions(+), 46 deletions(-)

diff --git a/lib/matplotlib/__init__.py b/lib/matplotlib/__init__.py
index b850a69d8d3a..95f6b4e8e66e 100644
--- a/lib/matplotlib/__init__.py
+++ b/lib/matplotlib/__init__.py
@@ -671,7 +671,8 @@ class RcParams(MutableMapping):
     def __init__(self, *args, **kwargs):
         self._rcvalues = ChainMap({})
         self.update(*args, **kwargs)
-        self._rcvalues.new_child()
+        self._rcvalues = self._rcvalues.new_child()
+        self._defaults = self._rcvalues.maps[-1]
 
     def _set(self, key, val):
         """
@@ -730,14 +731,12 @@ def __setitem__(self, key, val):
                 _api.warn_deprecated(
                     version, name=key, obj_type="rcparam", alternative=alt_key)
                 return
-            elif key == 'backend' or key == "default.backend":
+            elif key == 'backend':
                 if val is rcsetup._auto_backend_sentinel:
-                    if 'backend' in self or 'default.backend' in self:
+                    if 'backend' in self:
                         return
             try:
                 cval = self.validate[key](val)
-                # if key in self._single_key_set:
-                #     key = f"default.{key}"
             except ValueError as ve:
                 raise ValueError(f"Key {key}: {ve}") from None
             self._set(key, cval)
@@ -769,10 +768,8 @@ def __getitem__(self, key):
 
         return self._get(key)
 
-    def _get_default(self, key):
-        return self._rcvalues.maps[-1][key]
-
     def get_default(self, key):
+        """Return default value for the key set during initialization."""
         if key in _deprecated_map:
             version, alt_key, alt_val, inverse_alt = _deprecated_map[key]
             _api.warn_deprecated(
@@ -783,15 +780,13 @@ def get_default(self, key):
             version, alt_key = _deprecated_ignore_map[key]
             _api.warn_deprecated(
                 version, name=key, obj_type="rcparam", alternative=alt_key)
-            return self._get_default(alt_key) if alt_key else None
+            return self._defaults[alt_key] if alt_key else None
 
-        return self._get_default(key)
+        return self._defaults[key]
 
     def get_defaults(self):
         """Return default values set during initialization."""
-        defaults = self.copy()
-        defaults.clear()
-        return defaults
+        return self._defaults.copy()
 
     def _get_backend_or_none(self):
         """Get the requested backend, if any, without triggering resolution."""
@@ -845,7 +840,11 @@ def popitem(self):
         raise NotImplementedError(
             "popitem is not implemented for RcParams.")
 
+    @_api.deprecated("3.8")
     def clear(self):
+        pass
+
+    def reset(self):
         self._rcvalues.clear()
 
     def setdefault(self, key, default=None):
@@ -858,30 +857,6 @@ def setdefault(self, key, default=None):
         self[key] = default
         return default
 
-    def get(self, key, default=None):
-        try:
-            return self[key]
-        except KeyError as e:
-            return default
-
-    def update(self, other=(), /, **kwds):
-        """D.update([E, ]**F) -> None.  Update D from mapping/iterable E and F.
-        If E present and has a .keys() method, does:     for k in E: D[k] = E[k]
-        If E present and lacks .keys() method, does:     for (k, v) in E: D[k] = v
-        In either case, this is followed by: for k, v in F.items(): D[k] = v
-        """
-        if isinstance(other, Mapping):
-            for key in other:
-                self[key] = other[key]
-        elif hasattr(other, "keys"):
-            for key in other.keys():
-                self[key] = other[key]
-        else:
-            for key, value in other:
-                self[key] = value
-        for key, value in kwds.items():
-            self[key] = value
-
     def copy(self):
         return deepcopy(self)
 
@@ -1054,18 +1029,16 @@ def rc_params_from_file(fname, fail_on_error=False, use_default_template=True):
     # Strip leading comment.
     transform=lambda line: line[1:] if line.startswith("#") else line,
     fail_on_error=True)
-# for key in rcsetup._hardcoded_defaults:
-#     space, subkey = key.split(".")
-#     if not rcParams._namespace_maps[space]:
-#         rcParams._namespace_maps[space] = ChainMap({})
+rcParams._rcvalues = rcParams._rcvalues.parents
 rcParams.update(rcsetup._hardcoded_defaults)
 # Normally, the default matplotlibrc file contains *no* entry for backend (the
 # corresponding line starts with ##, not #; we fill on _auto_backend_sentinel
 # in that case.  However, packagers can set a different default backend
 # (resulting in a normal `#backend: foo` line) in which case we should *not*
 # fill in _auto_backend_sentinel.
-rcParams.setdefault("backend", rcsetup._auto_backend_sentinel)
 rcParams.update(_rc_params_in_file(matplotlib_fname()))
+rcParams._rcvalues = rcParams._rcvalues.new_child()
+rcParams.setdefault("backend", rcsetup._auto_backend_sentinel)
 rcParamsOrig = rcParams.copy()
 with _api.suppress_matplotlib_deprecation_warning():
     # This also checks that all rcParams are indeed listed in the template.
diff --git a/lib/matplotlib/tests/test_rcparams.py b/lib/matplotlib/tests/test_rcparams.py
index 8defa1735edf..dc4ff1f8cff5 100644
--- a/lib/matplotlib/tests/test_rcparams.py
+++ b/lib/matplotlib/tests/test_rcparams.py
@@ -662,8 +662,7 @@ def test_rcparams_getdefault():
 def test_rcparams_getdefaults():
     mpl.rc("image", lut=128)
     defaults = mpl.rcParams.get_defaults()
-    mpl.rcParams.clear()
-    assert defaults == mpl.rcParams
+    assert defaults == mpl.rcParams._defaults
 
 
 def test_rcdefaults():
@@ -680,7 +679,12 @@ def test_rcdefaults():
     assert mpl.rcParams["lines.linewidth"] == lw
 
 
-def test_rcparams_clear():
+def test_rcparams_reset():
     mpl.rcParams["image.lut"] = 128
-    mpl.rcParams.clear()
+    mpl.rcParams.reset()
     assert mpl.rcParams["image.lut"] == 256
+
+
+def test_rcparams_clear():
+    with pytest.raises(mpl.MatplotlibDeprecationWarning):
+        mpl.rcParams.clear()

From b1754a2e97b71ccfed41243ee3bf1a2425fa51a4 Mon Sep 17 00:00:00 2001
From: Chahak Mehta <chahakmehta013@gmail.com>
Date: Wed, 7 Jun 2023 22:06:31 -0700
Subject: [PATCH 20/22] Update delitem

---
 lib/matplotlib/__init__.py | 26 +++++++-------------------
 1 file changed, 7 insertions(+), 19 deletions(-)

diff --git a/lib/matplotlib/__init__.py b/lib/matplotlib/__init__.py
index 95f6b4e8e66e..7b8be618af23 100644
--- a/lib/matplotlib/__init__.py
+++ b/lib/matplotlib/__init__.py
@@ -794,12 +794,16 @@ def _get_backend_or_none(self):
         return None if backend is rcsetup._auto_backend_sentinel else backend
 
     def __delitem__(self, key):
+        if key not in self.validate:
+            raise KeyError(
+                f"{key} is not a valid rc parameter (see rcParams.keys() for "
+                f"a list of valid parameters)")
         try:
             del self._rcvalues[key]
         except KeyError as err:
             raise KeyError(
-                f"{key} is not a valid rc parameter (see rcParams.keys() for "
-                f"a list of valid parameters)") from err
+                f"No custom value set for {key}. Cannot delete default value."
+            ) from err
 
     def __contains__(self, key):
         return key in self._rcvalues
@@ -824,22 +828,6 @@ def __repr__(self):
     def __str__(self):
         return '\n'.join(map('{0[0]}: {0[1]}'.format, sorted(self._rcvalues.items())))
 
-    def pop(self, key):
-        keys, depth = self._split_key(key)
-        if depth == 1:
-            if key in self._single_key_set:
-                return self._namespace_mapping["default"][key]
-            else:
-                raise KeyError(
-                    f"{key} is not a valid rc parameter (see rcParams.keys() for "
-                    f"a list of valid parameters)")
-        elif depth == 2:
-            return self._namespace_mapping[keys[0]].pop(keys[1])
-
-    def popitem(self):
-        raise NotImplementedError(
-            "popitem is not implemented for RcParams.")
-
     @_api.deprecated("3.8")
     def clear(self):
         pass
@@ -1037,8 +1025,8 @@ def rc_params_from_file(fname, fail_on_error=False, use_default_template=True):
 # (resulting in a normal `#backend: foo` line) in which case we should *not*
 # fill in _auto_backend_sentinel.
 rcParams.update(_rc_params_in_file(matplotlib_fname()))
-rcParams._rcvalues = rcParams._rcvalues.new_child()
 rcParams.setdefault("backend", rcsetup._auto_backend_sentinel)
+rcParams._rcvalues = rcParams._rcvalues.new_child()
 rcParamsOrig = rcParams.copy()
 with _api.suppress_matplotlib_deprecation_warning():
     # This also checks that all rcParams are indeed listed in the template.

From faed9bacfd4c6018fa0d7349f272135852c7c3db Mon Sep 17 00:00:00 2001
From: Chahak Mehta <chahakmehta013@gmail.com>
Date: Sat, 14 Oct 2023 10:19:26 -0400
Subject: [PATCH 21/22] Make flake8 happy

---
 lib/matplotlib/__init__.pyi            | 8 ++++----
 lib/matplotlib/pyplot.py               | 7 ++++---
 lib/matplotlib/tests/test_offsetbox.py | 5 -----
 3 files changed, 8 insertions(+), 12 deletions(-)

diff --git a/lib/matplotlib/__init__.pyi b/lib/matplotlib/__init__.pyi
index 8691ef420166..d37ac6469770 100644
--- a/lib/matplotlib/__init__.pyi
+++ b/lib/matplotlib/__init__.pyi
@@ -32,12 +32,12 @@ __all__ = [
 import os
 from pathlib import Path
 
-from collections.abc import Callable, Generator
+from collections.abc import Callable, Generator, MutableMapping
 import contextlib
 from packaging.version import Version
 
 from matplotlib._api import MatplotlibDeprecationWarning
-from typing import Any, NamedTuple
+from typing import Any, NamedTuple, Self
 
 class _VersionInfo(NamedTuple):
     major: int
@@ -79,8 +79,8 @@ class RcParams(MutableMapping[str, Any]):
     def __delitem__(self, key: str) -> None: ...
     def __iter__(self) -> Generator[str, None, None]: ...
     def __len__(self) -> int: ...
-    def find_all(self, pattern: str) -> RcParams: ...
-    def copy(self) -> RcParams: ...
+    def find_all(self, pattern: str) -> Self: ...
+    def copy(self) -> Self: ...
 
 def rc_params(fail_on_error: bool = ...) -> RcParams: ...
 def rc_params_from_file(
diff --git a/lib/matplotlib/pyplot.py b/lib/matplotlib/pyplot.py
index 8c7b6a873882..5669ee82f2f3 100644
--- a/lib/matplotlib/pyplot.py
+++ b/lib/matplotlib/pyplot.py
@@ -67,6 +67,7 @@
 from matplotlib.gridspec import GridSpec, SubplotSpec
 from matplotlib import rcParams, get_backend, rcParamsOrig
 from matplotlib.rcsetup import interactive_bk as _interactive_bk
+from matplotlib.rcsetup import _auto_backend_sentinel
 from matplotlib.artist import Artist
 from matplotlib.axes import Axes, Subplot  # type: ignore
 from matplotlib.projections import PolarAxes  # type: ignore
@@ -302,7 +303,7 @@ def switch_backend(newbackend: str) -> None:
     # make sure the init is pulled up so we can assign to it later
     import matplotlib.backends
 
-    if newbackend is rcsetup._auto_backend_sentinel:
+    if newbackend is _auto_backend_sentinel:
         current_framework = cbook._get_running_interactive_framework()
         mapping = {'qt': 'qtagg',
                    'gtk3': 'gtk3agg',
@@ -2475,9 +2476,9 @@ def polar(*args, **kwargs) -> list[Line2D]:
 # is compatible with the current running interactive framework.
 if (rcParams["backend_fallback"]
         and rcParams._get_backend_or_none() in (  # type: ignore
-            set(rcsetup.interactive_bk) - {'WebAgg', 'nbAgg'})
+            set(_interactive_bk) - {'WebAgg', 'nbAgg'})
         and cbook._get_running_interactive_framework()):  # type: ignore
-    rcParams._set("backend", rcsetup._auto_backend_sentinel)  # type: ignore
+    rcParams._set("backend", _auto_backend_sentinel)  # type: ignore
 
 # fmt: on
 
diff --git a/lib/matplotlib/tests/test_offsetbox.py b/lib/matplotlib/tests/test_offsetbox.py
index edf17542fb17..49b55e4c9326 100644
--- a/lib/matplotlib/tests/test_offsetbox.py
+++ b/lib/matplotlib/tests/test_offsetbox.py
@@ -257,14 +257,9 @@ def test_anchoredtext_horizontal_alignment():
     ax.add_artist(text2)
 
 
-<<<<<<< HEAD
 @pytest.mark.parametrize("extent_kind", ["window_extent", "tightbbox"])
 def test_annotationbbox_extents(extent_kind):
     plt.rcParams.update(plt.rcParamsDefault)
-=======
-def test_annotationbbox_extents():
-    plt.rcParams.clear()
->>>>>>> 57d742c95e (Remove `rcParamsDefault`)
     fig, ax = plt.subplots(figsize=(4, 3), dpi=100)
 
     ax.axis([0, 1, 0, 1])

From dfbb73f3f1a544eca2449a0884a308bf8d468c8e Mon Sep 17 00:00:00 2001
From: Chahak Mehta <chahakmehta013@gmail.com>
Date: Mon, 23 Oct 2023 21:16:55 -0400
Subject: [PATCH 22/22] Remove unnecessary deprecation warning context

---
 lib/matplotlib/__init__.py | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/lib/matplotlib/__init__.py b/lib/matplotlib/__init__.py
index 7b8be618af23..623b22852e30 100644
--- a/lib/matplotlib/__init__.py
+++ b/lib/matplotlib/__init__.py
@@ -810,8 +810,7 @@ def __contains__(self, key):
 
     def __iter__(self):
         """Yield from sorted list of keys"""
-        with _api.suppress_matplotlib_deprecation_warning():
-            yield from sorted(self._rcvalues.keys())
+        yield from sorted(self._rcvalues.keys())
 
     def __len__(self):
         return len(self._rcvalues)

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