Added Test

Author: Impaler343

lib/matplotlib/collections.py

@@ -388,11 +388,10 @@ def draw(self, renderer):
         trans = self.get_transforms()
         facecolors = self.get_facecolor()
         edgecolors = self.get_edgecolor()
-        linewidths = np.nan_to_num(self._linewidths, nan=0, posinf=0).clip(0)
         do_single_path_optimization = False
         if (len(paths) == 1 and len(trans) <= 1 and
                 len(facecolors) == 1 and len(edgecolors) == 1 and
-                len(linewidths) == 1 and
+                len(self._linewidths) == 1 and
                 all(ls[1] is None for ls in self._linestyles) and
                 len(self._antialiaseds) == 1 and len(self._urls) == 1 and
                 self.get_hatch() is None):
@@ -413,7 +412,7 @@ def draw(self, renderer):
 
         if do_single_path_optimization:
             gc.set_foreground(tuple(edgecolors[0]))
-            gc.set_linewidth(linewidths[0])
+            gc.set_linewidth(self._linewidths[0])
             gc.set_dashes(*self._linestyles[0])
             gc.set_antialiased(self._antialiaseds[0])
             gc.set_url(self._urls[0])
@@ -434,7 +433,7 @@ def draw(self, renderer):
                     gc, transform.frozen(), [],
                     self.get_transforms(), offsets, offset_trf,
                     self.get_facecolor(), self.get_edgecolor(),
-                    linewidths, self._linestyles,
+                    self._linewidths, self._linestyles,
                     self._antialiaseds, self._urls,
                     "screen", hatchcolors=self.get_hatchcolor()
                 )
@@ -454,7 +453,7 @@ def draw(self, renderer):
                 # First draw paths within the gaps.
                 ipaths, ilinestyles = self._get_inverse_paths_linestyles()
                 args = [offsets, offset_trf, [mcolors.to_rgba("none")], self._gapcolor,
-                        linewidths, ilinestyles, self._antialiaseds, self._urls,
+                        self._linewidths, ilinestyles, self._antialiaseds, self._urls,
                         "screen"]
 
                 if hatchcolors_arg_supported:
@@ -479,7 +478,7 @@ def draw(self, renderer):
                             renderer.draw_path(gc0, path, transform, rgbFace)
 
             args = [offsets, offset_trf, self.get_facecolor(), self.get_edgecolor(),
-                    linewidths, self._linestyles, self._antialiaseds, self._urls,
+                    self._linewidths, self._linestyles, self._antialiaseds, self._urls,
                     "screen"]
 
             if hatchcolors_arg_supported:
@@ -665,6 +664,7 @@ def set_linewidth(self, lw):
         # scale all of the dash patterns.
         self._linewidths, self._linestyles = self._bcast_lwls(
             self._us_lw, self._us_linestyles)
+        self._linewidths = np.nan_to_num(self._linewidths, nan=0, posinf=0).clip(0)
         self.stale = True
 
     def set_linestyle(self, ls):

lib/matplotlib/tests/test_collections.py

@@ -1538,3 +1538,10 @@ def mock_draw_path_collection(self, gc, master_transform, paths, all_transforms,
     ax.add_collection(coll)
 
     plt.draw()
+
+
+@pytest.mark.parametrize('lw', [np.nan, -5.0, np.inf])
+def test_invalid_linewidths(lw):
+    lc = LineCollection([[(0, 0), (1, 1)]])
+    lc.set_linewidth(lw)
+    assert lc.get_linewidth() == 0.0