Don't import rcParams but rather use mpl.rcParams.

anntzer · anntzer · commit f03811297bc3 · 2020-02-04T19:50:20.000+01:00
This helps letting modules be imported early in the init process, even
before the rcParams object is constructed.

I didn't change all cases, just those needed to make matplotlib.scale
importable into matplotlib.colors.
diff --git a/doc/devel/contributing.rst b/doc/devel/contributing.rst
@@ -215,6 +215,11 @@ rules before submitting a pull request:
      import matplotlib.cbook as cbook
      import matplotlib.patches as mpatches
 
+  In general, Matplotlib modules should **not** import `.rcParams` using ``from
+  matplotlib import rcParams``, but rather access it as ``mpl.rcParams``.  This
+  is because some modules are imported very early, before the `.rcParams`
+  singleton is constructed.
+
 * If your change is a major new feature, add an entry to the ``What's new``
   section by adding a new file in ``doc/users/next_whats_new`` (see
   :file:`doc/users/next_whats_new/README.rst` for more information).
diff --git a/lib/matplotlib/path.py b/lib/matplotlib/path.py
@@ -14,7 +14,8 @@
 
 import numpy as np
 
-from . import _path, cbook, rcParams
+import matplotlib as mpl
+from . import _path, cbook
 from .cbook import _to_unmasked_float_array, simple_linear_interpolation
 
 
@@ -181,15 +182,15 @@ def _fast_from_codes_and_verts(cls, verts, codes, internals_from=None):
             pth._interpolation_steps = internals_from._interpolation_steps
         else:
             pth._should_simplify = True
-            pth._simplify_threshold = rcParams['path.simplify_threshold']
+            pth._simplify_threshold = mpl.rcParams['path.simplify_threshold']
             pth._interpolation_steps = 1
         return pth
 
     def _update_values(self):
-        self._simplify_threshold = rcParams['path.simplify_threshold']
+        self._simplify_threshold = mpl.rcParams['path.simplify_threshold']
         self._should_simplify = (
             self._simplify_threshold > 0 and
-            rcParams['path.simplify'] and
+            mpl.rcParams['path.simplify'] and
             len(self._vertices) >= 128 and
             (self._codes is None or np.all(self._codes <= Path.LINETO))
         )
diff --git a/lib/matplotlib/scale.py b/lib/matplotlib/scale.py
@@ -13,7 +13,8 @@
 import numpy as np
 from numpy import ma
 
-from matplotlib import cbook, docstring, rcParams
+import matplotlib as mpl
+from matplotlib import cbook, docstring
 from matplotlib.ticker import (
     NullFormatter, ScalarFormatter, LogFormatterSciNotation, LogitFormatter,
     NullLocator, LogLocator, AutoLocator, AutoMinorLocator,
@@ -108,8 +109,8 @@ def set_default_locators_and_formatters(self, axis):
         axis.set_major_formatter(ScalarFormatter())
         axis.set_minor_formatter(NullFormatter())
         # update the minor locator for x and y axis based on rcParams
-        if (axis.axis_name == 'x' and rcParams['xtick.minor.visible']
-            or axis.axis_name == 'y' and rcParams['ytick.minor.visible']):
+        if (axis.axis_name == 'x' and mpl.rcParams['xtick.minor.visible']
+            or axis.axis_name == 'y' and mpl.rcParams['ytick.minor.visible']):
             axis.set_minor_locator(AutoMinorLocator())
         else:
             axis.set_minor_locator(NullLocator())
@@ -193,8 +194,8 @@ def set_default_locators_and_formatters(self, axis):
         axis.set_major_formatter(ScalarFormatter())
         axis.set_minor_formatter(NullFormatter())
         # update the minor locator for x and y axis based on rcParams
-        if (axis.axis_name == 'x' and rcParams['xtick.minor.visible']
-            or axis.axis_name == 'y' and rcParams['ytick.minor.visible']):
+        if (axis.axis_name == 'x' and mpl.rcParams['xtick.minor.visible']
+            or axis.axis_name == 'y' and mpl.rcParams['ytick.minor.visible']):
             axis.set_minor_locator(AutoMinorLocator())
         else:
             axis.set_minor_locator(NullLocator())
diff --git a/lib/matplotlib/ticker.py b/lib/matplotlib/ticker.py
@@ -168,8 +168,10 @@
 import logging
 import locale
 import math
+
 import numpy as np
-from matplotlib import rcParams
+
+import matplotlib as mpl
 from matplotlib import cbook
 from matplotlib import transforms as mtransforms
 
@@ -291,7 +293,7 @@ def fix_minus(s):
         :rc:`axes.unicode_minus`.
         """
         return (s.replace('-', '\N{MINUS SIGN}')
-                if rcParams['axes.unicode_minus']
+                if mpl.rcParams['axes.unicode_minus']
                 else s)
 
     def _set_locator(self, locator):
@@ -515,19 +517,20 @@ def __init__(self, useOffset=None, useMathText=None, useLocale=None):
         # and scientific notation in mathtext
 
         if useOffset is None:
-            useOffset = rcParams['axes.formatter.useoffset']
-        self._offset_threshold = rcParams['axes.formatter.offset_threshold']
+            useOffset = mpl.rcParams['axes.formatter.useoffset']
+        self._offset_threshold = \
+            mpl.rcParams['axes.formatter.offset_threshold']
         self.set_useOffset(useOffset)
-        self._usetex = rcParams['text.usetex']
+        self._usetex = mpl.rcParams['text.usetex']
         if useMathText is None:
-            useMathText = rcParams['axes.formatter.use_mathtext']
+            useMathText = mpl.rcParams['axes.formatter.use_mathtext']
         self.set_useMathText(useMathText)
         self.orderOfMagnitude = 0
         self.format = ''
         self._scientific = True
-        self._powerlimits = rcParams['axes.formatter.limits']
+        self._powerlimits = mpl.rcParams['axes.formatter.limits']
         if useLocale is None:
-            useLocale = rcParams['axes.formatter.use_locale']
+            useLocale = mpl.rcParams['axes.formatter.use_locale']
         self._useLocale = useLocale
 
     def get_useOffset(self):
@@ -548,7 +551,7 @@ def get_useLocale(self):
 
     def set_useLocale(self, val):
         if val is None:
-            self._useLocale = rcParams['axes.formatter.use_locale']
+            self._useLocale = mpl.rcParams['axes.formatter.use_locale']
         else:
             self._useLocale = val
 
@@ -559,7 +562,7 @@ def get_useMathText(self):
 
     def set_useMathText(self, val):
         if val is None:
-            self._useMathText = rcParams['axes.formatter.use_mathtext']
+            self._useMathText = mpl.rcParams['axes.formatter.use_mathtext']
         else:
             self._useMathText = val
 
@@ -882,7 +885,7 @@ def __init__(self, base=10.0, labelOnlyBase=False,
         self._base = float(base)
         self.labelOnlyBase = labelOnlyBase
         if minor_thresholds is None:
-            if rcParams['_internal.classic_mode']:
+            if mpl.rcParams['_internal.classic_mode']:
                 minor_thresholds = (0, 0)
             else:
                 minor_thresholds = (1, 0.4)
@@ -1075,8 +1078,8 @@ def __call__(self, x, pos=None):
 
         The position *pos* is ignored.
         """
-        usetex = rcParams['text.usetex']
-        min_exp = rcParams['axes.formatter.min_exponent']
+        usetex = mpl.rcParams['text.usetex']
+        min_exp = mpl.rcParams['axes.formatter.min_exponent']
 
         if x == 0:  # Symlog
             return r'$\mathdefault{0}$'
@@ -1400,7 +1403,7 @@ def get_usetex(self):
 
     def set_usetex(self, val):
         if val is None:
-            self._usetex = rcParams['text.usetex']
+            self._usetex = mpl.rcParams['text.usetex']
         else:
             self._usetex = val
 
@@ -1411,7 +1414,7 @@ def get_useMathText(self):
 
     def set_useMathText(self, val):
         if val is None:
-            self._useMathText = rcParams['axes.formatter.use_mathtext']
+            self._useMathText = mpl.rcParams['axes.formatter.use_mathtext']
         else:
             self._useMathText = val
 
@@ -1580,7 +1583,7 @@ def symbol(self):
         symbol = self._symbol
         if not symbol:
             symbol = ''
-        elif rcParams['text.usetex'] and not self._is_latex:
+        elif mpl.rcParams['text.usetex'] and not self._is_latex:
             # Source: http://www.personal.ceu.hu/tex/specchar.htm
             # Backslash must be first for this to work correctly since
             # it keeps getting added in
@@ -1876,7 +1879,7 @@ def view_limits(self, vmin, vmax):
             vmin -= 1
             vmax += 1
 
-        if rcParams['axes.autolimit_mode'] == 'round_numbers':
+        if mpl.rcParams['axes.autolimit_mode'] == 'round_numbers':
             exponent, remainder = divmod(
                 math.log10(vmax - vmin), math.log10(max(self.numticks - 1, 1)))
             exponent -= (remainder < .5)
@@ -1919,7 +1922,7 @@ def view_limits(self, dmin, dmax):
         Set the view limits to the nearest multiples of base that
         contain the data.
         """
-        if rcParams['axes.autolimit_mode'] == 'round_numbers':
+        if mpl.rcParams['axes.autolimit_mode'] == 'round_numbers':
             vmin = self._edge.le(dmin) * self._edge.step
             vmax = self._edge.ge(dmax) * self._edge.step
             if vmin == vmax:
@@ -2145,7 +2148,7 @@ def _raw_ticks(self, vmin, vmax):
         istep = np.nonzero(steps >= raw_step)[0][0]
 
         # Classic round_numbers mode may require a larger step.
-        if rcParams['axes.autolimit_mode'] == 'round_numbers':
+        if mpl.rcParams['axes.autolimit_mode'] == 'round_numbers':
             for istep in range(istep, len(steps)):
                 step = steps[istep]
                 best_vmin = (_vmin // step) * step
@@ -2205,7 +2208,7 @@ def view_limits(self, dmin, dmax):
         dmin, dmax = mtransforms.nonsingular(
             dmin, dmax, expander=1e-12, tiny=1e-13)
 
-        if rcParams['axes.autolimit_mode'] == 'round_numbers':
+        if mpl.rcParams['axes.autolimit_mode'] == 'round_numbers':
             return self._raw_ticks(dmin, dmax)[[0, -1]]
         else:
             return dmin, dmax
@@ -2317,7 +2320,7 @@ def __init__(self, base=10.0, subs=(1.0,), numdecs=4, numticks=None):
 
         """
         if numticks is None:
-            if rcParams['_internal.classic_mode']:
+            if mpl.rcParams['_internal.classic_mode']:
                 numticks = 15
             else:
                 numticks = 'auto'
@@ -2420,7 +2423,7 @@ def tick_values(self, vmin, vmax):
 
         # Get decades between major ticks.
         stride = (max(math.ceil(numdec / (numticks - 1)), 1)
-                  if rcParams['_internal.classic_mode'] else
+                  if mpl.rcParams['_internal.classic_mode'] else
                   (numdec + 1) // numticks + 1)
 
         # Does subs include anything other than 1?  Essentially a hack to know
@@ -2469,7 +2472,7 @@ def view_limits(self, vmin, vmax):
             vmax = math.ceil(math.log(vmax) / math.log(b))
             vmin = b ** (vmax - self.numdecs)
 
-        if rcParams['axes.autolimit_mode'] == 'round_numbers':
+        if mpl.rcParams['axes.autolimit_mode'] == 'round_numbers':
             vmin = _decade_less_equal(vmin, self._base)
             vmax = _decade_greater_equal(vmax, self._base)
 
@@ -2627,7 +2630,7 @@ def view_limits(self, vmin, vmax):
         if vmax < vmin:
             vmin, vmax = vmax, vmin
 
-        if rcParams['axes.autolimit_mode'] == 'round_numbers':
+        if mpl.rcParams['axes.autolimit_mode'] == 'round_numbers':
             vmin = _decade_less_equal(vmin, b)
             vmax = _decade_greater_equal(vmax, b)
             if vmin == vmax:
@@ -2797,7 +2800,7 @@ def __init__(self):
         To know the values of the non-public parameters, please have a
         look to the defaults of `~matplotlib.ticker.MaxNLocator`.
         """
-        if rcParams['_internal.classic_mode']:
+        if mpl.rcParams['_internal.classic_mode']:
             nbins = 9
             steps = [1, 2, 5, 10]
         else:
