Move cbook._warn_external to _api.warn_external.

timhoffm · timhoffm · commit 5a45fc2aa470 · 2020-10-19T11:01:54.000+02:00
This is needed right now to not re-import cbook from _api.deprecation.
It's intended anyway, but changing all occurences in the code is left
for another time to keep this PR reasonably sized.
diff --git a/lib/matplotlib/_api/__init__.py b/lib/matplotlib/_api/__init__.py
@@ -1,4 +1,7 @@
 import itertools
+import re
+import sys
+import warnings
 
 
 def check_in_list(_values, *, _print_supported_values=True, **kwargs):
@@ -93,3 +96,25 @@ def check_getitem(_mapping, **kwargs):
         raise ValueError(
             "{!r} is not a valid value for {}; supported values are {}"
             .format(v, k, ', '.join(map(repr, mapping)))) from None
+
+
+def warn_external(message, category=None):
+    """
+    `warnings.warn` wrapper that sets *stacklevel* to "outside Matplotlib".
+
+    The original emitter of the warning can be obtained by patching this
+    function back to `warnings.warn`, i.e. ``_api.warn_external =
+    warnings.warn`` (or ``functools.partial(warnings.warn, stacklevel=2)``,
+    etc.).
+    """
+    frame = sys._getframe()
+    for stacklevel in itertools.count(1):  # lgtm[py/unused-loop-variable]
+        if frame is None:
+            # when called in embedded context may hit frame is None
+            break
+        if not re.match(r"\A(matplotlib|mpl_toolkits)(\Z|\.(?!tests\.))",
+                        # Work around sphinx-gallery not setting __name__.
+                        frame.f_globals.get("__name__", "")):
+            break
+        frame = frame.f_back
+    warnings.warn(message, category, stacklevel)
diff --git a/lib/matplotlib/_api/deprecation.py b/lib/matplotlib/_api/deprecation.py
@@ -105,8 +105,8 @@ def warn_deprecated(
     warning = _generate_deprecation_warning(
         since, message, name, alternative, pending, obj_type, addendum,
         removal=removal)
-    from ..cbook import _warn_external
-    _warn_external(warning, category=MatplotlibDeprecationWarning)
+    from . import warn_external
+    warn_external(warning, category=MatplotlibDeprecationWarning)
 
 
 def deprecated(since, *, message='', name='', alternative='', pending=False,
diff --git a/lib/matplotlib/cbook/__init__.py b/lib/matplotlib/cbook/__init__.py
@@ -29,6 +29,7 @@
 
 import matplotlib
 from matplotlib import _c_internal_utils
+from matplotlib._api import warn_external as _warn_external
 from matplotlib._api.deprecation import (
     deprecated, warn_deprecated,
     _rename_parameter, _delete_parameter, _make_keyword_only,
@@ -2096,30 +2097,6 @@ def _setattr_cm(obj, **kwargs):
                 setattr(obj, attr, orig)
 
 
-def _warn_external(message, category=None):
-    """
-    `warnings.warn` wrapper that sets *stacklevel* to "outside Matplotlib".
-
-    The original emitter of the warning can be obtained by patching this
-    function back to `warnings.warn`, i.e. ``cbook._warn_external =
-    warnings.warn`` (or ``functools.partial(warnings.warn, stacklevel=2)``,
-    etc.).
-
-    :meta public:
-    """
-    frame = sys._getframe()
-    for stacklevel in itertools.count(1):  # lgtm[py/unused-loop-variable]
-        if frame is None:
-            # when called in embedded context may hit frame is None
-            break
-        if not re.match(r"\A(matplotlib|mpl_toolkits)(\Z|\.(?!tests\.))",
-                        # Work around sphinx-gallery not setting __name__.
-                        frame.f_globals.get("__name__", "")):
-            break
-        frame = frame.f_back
-    warnings.warn(message, category, stacklevel)
-
-
 class _OrderedSet(collections.abc.MutableSet):
     def __init__(self):
         self._od = collections.OrderedDict()
diff --git a/lib/matplotlib/cm.py b/lib/matplotlib/cm.py
@@ -24,7 +24,6 @@
 from matplotlib import _api, colors, cbook
 from matplotlib._cm import datad
 from matplotlib._cm_listed import cmaps as cmaps_listed
-from matplotlib.cbook import _warn_external
 
 
 LUTSIZE = mpl.rcParams['image.lut']
@@ -150,7 +149,7 @@ def register_cmap(name=None, cmap=None, *, override_builtin=False):
             raise ValueError(msg)
         else:
             msg = f"Trying to register the cmap {name!r} which already exists."
-            _warn_external(msg)
+            _api.warn_external(msg)
 
     if not isinstance(cmap, colors.Colormap):
         raise ValueError("You must pass a Colormap instance. "
diff --git a/lib/matplotlib/pyplot.py b/lib/matplotlib/pyplot.py
@@ -2987,8 +2987,8 @@ def quiverkey(Q, X, Y, U, label, **kw):
 def scatter(
         x, y, s=None, c=None, marker=None, cmap=None, norm=None,
         vmin=None, vmax=None, alpha=None, linewidths=None,
-        verts=_api.deprecation._deprecated_parameter,
-        edgecolors=None, *, plotnonfinite=False, data=None, **kwargs):
+        verts=_api.deprecation._deprecated_parameter, edgecolors=None,
+        *, plotnonfinite=False, data=None, **kwargs):
     __ret = gca().scatter(
         x, y, s=s, c=c, marker=marker, cmap=cmap, norm=norm,
         vmin=vmin, vmax=vmax, alpha=alpha, linewidths=linewidths,
