matplotlib
diff --git a/‎.flake8
Lines changed: 0 additions & 1 deletion b/‎.flake8
Lines changed: 0 additions & 1 deletion
diff --git a/‎lib/matplotlib/__init__.py
Lines changed: 27 additions & 22 deletions b/‎lib/matplotlib/__init__.py
Lines changed: 27 additions & 22 deletions
diff --git a/‎lib/matplotlib/cbook/__init__.py
Lines changed: 1 addition & 1 deletion b/‎lib/matplotlib/cbook/__init__.py
Lines changed: 1 addition & 1 deletion
@@ -35,7 +35,6 @@ per-file-ignores =
     lib/matplotlib/_mathtext_data.py: E203, E261
     lib/matplotlib/font_manager.py: E203, E221, E251, E501
     lib/matplotlib/mathtext.py: E221, E251
-    lib/matplotlib/rcsetup.py: E501
     lib/matplotlib/tests/test_mathtext.py: E501
     lib/matplotlib/transforms.py: E201, E202, E203
     lib/matplotlib/tri/triinterpolate.py: E201, E221
 
@@ -139,7 +139,7 @@
 from matplotlib.cbook import (
     MatplotlibDeprecationWarning, dedent, get_label, sanitize_sequence)
 from matplotlib.cbook import mplDeprecation  # deprecated
-from matplotlib.rcsetup import defaultParams, validate_backend, cycler
+from matplotlib.rcsetup import validate_backend, cycler
 
 import numpy
 
@@ -614,7 +614,8 @@ def get_cachedir():
     return _get_config_or_cache_dir(_get_xdg_cache_dir())
 
 
-def _get_data_path():
+@_logged_cached('matplotlib data path: %s')
+def get_data_path():
     """Return the path to matplotlib data."""
 
     if 'MATPLOTLIBDATA' in os.environ:
@@ -655,13 +656,6 @@ def get_candidate_paths():
     raise RuntimeError('Could not find the matplotlib data files')
 
 
-@_logged_cached('matplotlib data path: %s')
-def get_data_path():
-    if defaultParams['datapath'][0] is None:
-        defaultParams['datapath'][0] = _get_data_path()
-    return defaultParams['datapath'][0]
-
-
 @cbook.deprecated("3.1")
 def get_py2exe_datafiles():
     data_path = Path(get_data_path())
@@ -749,9 +743,7 @@ class RcParams(MutableMapping, dict):
     :ref:`customizing-with-matplotlibrc-files`
     """
 
-    validate = {key: converter
-                for key, (default, converter) in defaultParams.items()
-                if key not in _all_deprecated}
+    validate = rcsetup._validators
 
     # validate values on the way in
     def __init__(self, *args, **kwargs):
@@ -807,6 +799,9 @@ def __getitem__(self, key):
                 from matplotlib import pyplot as plt
                 plt.switch_backend(rcsetup._auto_backend_sentinel)
 
+        elif key == "datapath":
+            return get_data_path()
+
         return dict.__getitem__(self, key)
 
     def __repr__(self):
@@ -916,7 +911,7 @@ def _rc_params_in_file(fname, fail_on_error=False):
     config = RcParams()
 
     for key, (val, line, line_no) in rc_temp.items():
-        if key in defaultParams:
+        if key in rcsetup._validators:
             if fail_on_error:
                 config[key] = val  # try to convert to proper type or raise
             else:
@@ -962,11 +957,8 @@ def rc_params_from_file(fname, fail_on_error=False, use_default_template=True):
     if not use_default_template:
         return config_from_file
 
-    iter_params = defaultParams.items()
     with cbook._suppress_matplotlib_deprecation_warning():
-        config = RcParams([(key, default) for key, (default, _) in iter_params
-                           if key not in _all_deprecated])
-    config.update(config_from_file)
+        config = RcParams({**rcParamsDefault, **config_from_file})
 
     if config['datapath'] is None:
         config['datapath'] = get_data_path()
@@ -984,15 +976,28 @@ def rc_params_from_file(fname, fail_on_error=False, use_default_template=True):
     return config
 
 
-# this is the instance used by the matplotlib classes
-rcParams = rc_params()
+# 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"), fail_on_error=True)
+with cbook._suppress_matplotlib_deprecation_warning():
+    dict.update(rcParamsDefault, rcsetup._hardcoded_defaults)
+
+rcParams = RcParams()  # The global instance.
+with cbook._suppress_matplotlib_deprecation_warning():
+    dict.update(rcParams, dict.items(rcParamsDefault))
+    dict.update(rcParams, _rc_params_in_file(matplotlib_fname()))
 
 with cbook._suppress_matplotlib_deprecation_warning():
+    defaultParams = rcsetup.defaultParams = {  # Left only for backcompat.
+        # We want to resolve deprecated rcParams, but not backend...
+        key: [(rcsetup._auto_backend_sentinel if key == "backend" else
+               rcParamsDefault[key]),
+< 9E7A /span>
validator]              validator]
+        for key, validator in rcsetup._validators.items()}
     rcParamsOrig = RcParams(rcParams.copy())
-    rcParamsDefault = RcParams([(key, default) for key, (default, converter) in
-                                defaultParams.items()
-                                if key not in _all_deprecated])
 
 if rcParams['axes.formatter.use_locale']:
     locale.setlocale(locale.LC_ALL, '')
 
@@ -439,7 +439,7 @@ def get_sample_data(fname, asfileobj=True):
 
     If the filename ends in .gz, the file is implicitly ungzipped.
     """
-    path = Path(matplotlib._get_data_path(), 'sample_data', fname)
+    path = _get_data_path('sample_data', fname)
     if asfileobj:
         suffix = path.suffix.lower()
         if suffix == '.gz':