Merge pull request astropy#15011 from meeseeksmachine/auto-backport-o…

…f-pr-15004-on-v5.3.x

Backport PR astropy#15004 on branch v5.3.x (MNT: Compatibility with matplotlib 3.8)

astropy/visualization/wcsaxes/coordinate_helpers.py

@@ -23,10 +23,10 @@
 from .grid_paths import get_gridline_path, get_lon_lat_path
 from .ticklabels import TickLabels
 from .ticks import Ticks
+from .utils import MATPLOTLIB_LT_3_8
 
 __all__ = ["CoordinateHelper"]
 
-
 # Matplotlib's gridlines use Line2D, but ours use PathPatch.
 # Patches take a slightly different format of linestyle argument.
 LINES_TO_PATCHES_LINESTYLE = {
@@ -618,9 +618,13 @@ def _draw_grid(self, renderer):
                     p.draw(renderer)
 
             elif self._grid is not None:
-                for line in self._grid.collections:
-                    line.set(**self.grid_lines_kwargs)
-                    line.draw(renderer)
+                if MATPLOTLIB_LT_3_8:
+                    for line in self._grid.collections:
+                        line.set(**self.grid_lines_kwargs)
+                        line.draw(renderer)
+                else:
+                    self._grid.set(**self.grid_lines_kwargs)
+                    self._grid.draw(renderer)
 
         renderer.close_group("grid lines")
 
@@ -1123,8 +1127,11 @@ def _get_gridline(self, xy_world, pixel, xy_world_round):
 
     def _clear_grid_contour(self):
         if hasattr(self, "_grid") and self._grid:
-            for line in self._grid.collections:
-                line.remove()
+            if MATPLOTLIB_LT_3_8:
+                for line in self._grid.collections:
+                    line.remove()
+            else:
+                self._grid.remove()
 
     def _update_grid_contour(self):
         if self.coord_index is None:

astropy/visualization/wcsaxes/utils.py

@@ -1,10 +1,11 @@
 # Licensed under a 3-clause BSD style license - see LICENSE.rst
 
-
+import matplotlib
 import numpy as np
 
 from astropy import units as u
 from astropy.coordinates import BaseCoordinateFrame, UnitSphericalRepresentation
+from astropy.utils.introspection import minversion
 
 __all__ = [
     "select_step_degree",
@@ -13,6 +14,8 @@
     "transform_contour_set_inplace",
 ]
 
+MATPLOTLIB_LT_3_8 = not minversion(matplotlib, "3.8.dev")
+
 
 def select_step_degree(dv):
     # Modified from axis_artist, supports astropy.units
@@ -136,17 +139,28 @@ def transform_contour_set_inplace(cset, transform):
     pos_level = []
     pos_segments = []
 
-    for collection in cset.collections:
-        paths = collection.get_paths()
-        if len(paths) == 0:
-            continue
-        all_paths.append(paths)
-        # The last item in pos isn't needed for np.split and in fact causes
-        # issues if we keep it because it will cause an extra empty array to be
-        # returned.
-        pos = np.cumsum([len(x) for x in paths])
-        pos_segments.append(pos[:-1])
-        pos_level.append(pos[-1])
+    if MATPLOTLIB_LT_3_8:
+        for collection in cset.collections:
+            paths = collection.get_paths()
+            if len(paths) == 0:
+                continue
+            all_paths.append(paths)
+            # The last item in pos isn't needed for np.split and in fact causes
+            # issues if we keep it because it will cause an extra empty array to be
+            # returned.
+            pos = np.cumsum([len(x) for x in paths])
+            pos_segments.append(pos[:-1])
+            pos_level.append(pos[-1])
+    else:
+        paths = cset.get_paths()
+        if len(paths) > 0:
+            all_paths.append(paths)
+            # The last item in pos isn't needed for np.split and in fact causes
+            # issues if we keep it because it will cause an extra empty array to be
+            # returned.
+            pos = np.cumsum([len(x) for x in paths])
+            pos_segments.append(pos[:-1])
+            pos_level.append(pos[-1])
 
     # As above the last item isn't needed
     pos_level = np.cumsum(pos_level)[:-1]