deprecate boxplot:vertical rcparam

Author: saranti

doc/api/next_api_changes/deprecations/28074-TS.rst

@@ -1,7 +1,9 @@
-``boxplot`` and ``bxp`` *vert* parameter
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+``boxplot`` and ``bxp`` *vert* parameter, and ``rcParams["boxplot.vertical"]``
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 The parameter *vert: bool* has been deprecated on `~.Axes.boxplot` and
-`~.Axes.bxp`.
-It is replaced by *orientation: {"vertical", "horizontal"}* for API
-consistency.
+`~.Axes.bxp`. It is replaced by *orientation: {"vertical", "horizontal"}*
+for API consistency.
+
+``rcParams["boxplot.vertical"]``, which controlled the orientation of ``boxplot``,
+is deprecated without replacement.

lib/matplotlib/axes/_axes.py

@@ -4060,6 +4060,8 @@ def boxplot(self, x, notch=None, sym=None, vert=None,
                                        labels=tick_labels, autorange=autorange)
         if notch is None:
             notch = mpl.rcParams['boxplot.notch']
+        if vert is None:
+            vert = mpl.rcParams['boxplot.vertical']
         if patch_artist is None:
             patch_artist = mpl.rcParams['boxplot.patchartist']
         if meanline is None:
@@ -4359,17 +4361,23 @@ def merge_kw_rc(subkey, explicit, zdelta=0, usemarker=True):
             mean_kw[removed_prop] = ''
 
         # vert and orientation parameters are linked until vert's
-        # deprecation period expires. If both are selected,
-        # vert takes precedence.
-        if vert is not None:
+        # deprecation period expires. vert only takes precedence and
+        # raises a deprecation warning if set to False.
+        if vert is False:
             _api.warn_deprecated(
                 "3.10",
                 name="vert: bool",
                 alternative="orientation: {'vertical', 'horizontal'}"
                 )
-            orientation = 'vertical' if vert else 'horizontal'
+            orientation = 'horizontal'
         _api.check_in_list(['horizontal', 'vertical'], orientation=orientation)
 
+        if not mpl.rcParams['boxplot.vertical']:
+            _api.warn_deprecated(
+                "3.10",
+                name='boxplot.vertical', obj_type="rcparam"
+            )
+
         # vertical or horizontal plot?
         maybe_swap = slice(None) if orientation == 'vertical' else slice(None, None, -1)
 

lib/matplotlib/mpl-data/stylelib/classic.mplstyle

@@ -380,7 +380,6 @@ boxplot.showbox: True
 boxplot.showcaps: True
 boxplot.showfliers: True
 boxplot.showmeans: False
-boxplot.vertical: True
 boxplot.whiskerprops.color: b
 boxplot.whiskerprops.linestyle: --
 boxplot.whiskerprops.linewidth: 1.0