From 7c9e266e5a2460391700a54da1c14e35205536a6 Mon Sep 17 00:00:00 2001
From: Elliott Sales de Andrade <quantum.analyst@gmail.com>
Date: Sat, 31 Aug 2019 04:24:59 -0400
Subject: [PATCH 4/4] Use drawstyle instead of linestyle in plot.step.

Mixing the two is deprecated in Matplotlib 3.1, and breaks the doc build
if warnings are set to errors (which they are in new IPython sphinx
extensions.)

Signed-off-by: Elliott Sales de Andrade <quantum.analyst@gmail.com>
---
 xarray/plot/plot.py  | 18 +++++++++---------
 xarray/plot/utils.py |  4 ++--
 2 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/xarray/plot/plot.py b/xarray/plot/plot.py
index 98131887..302cac05 100644
--- a/xarray/plot/plot.py
+++ b/xarray/plot/plot.py
@@ -329,7 +329,7 @@ def line(
     return primitive
 
 
-def step(darray, *args, where="pre", linestyle=None, ls=None, **kwargs):
+def step(darray, *args, where="pre", drawstyle=None, ds=None, **kwargs):
     """
     Step plot of DataArray index against values
 
@@ -359,16 +359,16 @@ def step(darray, *args, where="pre", linestyle=None, ls=None, **kwargs):
     if where not in {"pre", "post", "mid"}:
         raise ValueError("'where' argument to step must be " "'pre', 'post' or 'mid'")
 
-    if ls is not None:
-        if linestyle is None:
-            linestyle = ls
+    if ds is not None:
+        if drawstyle is None:
+            drawstyle = ds
         else:
-            raise TypeError("ls and linestyle are mutually exclusive")
-    if linestyle is None:
-        linestyle = ""
-    linestyle = "steps-" + where + linestyle
+            raise TypeError("ds and drawstyle are mutually exclusive")
+    if drawstyle is None:
+        drawstyle = ""
+    drawstyle = "steps-" + where + drawstyle
 
-    return line(darray, *args, linestyle=linestyle, **kwargs)
+    return line(darray, *args, drawstyle=drawstyle, **kwargs)
 
 
 def hist(
diff --git a/xarray/plot/utils.py b/xarray/plot/utils.py
index 6eec7c6b..08991e08 100644
--- a/xarray/plot/utils.py
+++ b/xarray/plot/utils.py
@@ -461,7 +461,7 @@ def _resolve_intervals_1dplot(xval, yval, xlabel, ylabel, kwargs):
     """
 
     # Is it a step plot? (see matplotlib.Axes.step)
-    if kwargs.get("linestyle", "").startswith("steps-"):
+    if kwargs.get("drawstyle", "").startswith("steps-"):
 
         # Convert intervals to double points
         if _valid_other_type(np.array([xval, yval]), [pd.Interval]):
@@ -472,7 +472,7 @@ def _resolve_intervals_1dplot(xval, yval, xlabel, ylabel, kwargs):
             yval, xval = _interval_to_double_bound_points(yval, xval)
 
         # Remove steps-* to be sure that matplotlib is not confused
-        del kwargs["linestyle"]
+        del kwargs["drawstyle"]
 
     # Is it another kind of plot?
     else:
-- 
2.21.1