From dafc5e080cb94ccefd8116a03ff6228fcedaaa50 Mon Sep 17 00:00:00 2001
From: Antony Lee <anntzer.lee@gmail.com>
Date: Tue, 25 Sep 2018 13:12:21 +0200
Subject: [PATCH 1/2] Don't warn in show() when running a non-interactive
 backened headless.

On Linux, $DISPLAY is unset, then we can't run a GUI toolkit anyways, so
don't warn about that in `show()`.

Delete the Note in the docstring which was redundant with the Parameters
entry.
---
 lib/matplotlib/figure.py | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/lib/matplotlib/figure.py b/lib/matplotlib/figure.py
index 9afca6ff81eb..819525482cb7 100644
--- a/lib/matplotlib/figure.py
+++ b/lib/matplotlib/figure.py
@@ -18,7 +18,7 @@
 import numpy as np
 
 from matplotlib import rcParams
-from matplotlib import docstring
+from matplotlib import backends, docstring
 from matplotlib import __version__ as _mpl_version
 from matplotlib import get_backend
 
@@ -415,12 +415,8 @@ def show(self, warn=True):
         Parameters
         ----------
         warn : bool
-            If ``True``, issue warning when called on a non-GUI backend
-
-        Notes
-        -----
-        For non-GUI backends, this does nothing, in which case a warning will
-        be issued if *warn* is ``True`` (default).
+            If ``True`` and we are not running headless (i.e. on Linux with an
+            unset DISPLAY), issue warning when called on a non-GUI backend.
         """
         try:
             manager = getattr(self.canvas, 'manager')
@@ -436,7 +432,8 @@ def show(self, warn=True):
                 return
             except NonGuiException:
                 pass
-        if warn:
+        if (backends._get_running_interactive_framework() != "headless"
+                and warn):
             warnings.warn('Matplotlib is currently using %s, which is a '
                           'non-GUI backend, so cannot show the figure.'
                           % get_backend())

From 0201ad64edd0e9132107d181d19a4bca136c1399 Mon Sep 17 00:00:00 2001
From: Antony Lee <anntzer.lee@gmail.com>
Date: Fri, 28 Sep 2018 13:58:41 +0200
Subject: [PATCH 2/2] Don't mock wx in docs build.

Otherwise, wx.GetApp() returns a truthy value and the backend switching
machinery believes that a wx event loop is running, leading to warnings
about show() not doing anything with agg.
---
 doc/api/backend_wxagg_api.rst      | 10 ++++++----
 doc/sphinxext/mock_gui_toolkits.py | 15 ---------------
 2 files changed, 6 insertions(+), 19 deletions(-)

diff --git a/doc/api/backend_wxagg_api.rst b/doc/api/backend_wxagg_api.rst
index 67c5a00be546..9005cfdfea80 100644
--- a/doc/api/backend_wxagg_api.rst
+++ b/doc/api/backend_wxagg_api.rst
@@ -2,7 +2,9 @@
 :mod:`matplotlib.backends.backend_wxagg`
 ========================================
 
-.. automodule:: matplotlib.backends.backend_wxagg
-   :members:
-   :undoc-members:
-   :show-inheritance:
+**NOTE** Not included, to avoid adding a dependency to building the docs.
+
+.. .. automodule:: matplotlib.backends.backend_wxagg
+..    :members:
+..    :undoc-members:
+..    :show-inheritance:
diff --git a/doc/sphinxext/mock_gui_toolkits.py b/doc/sphinxext/mock_gui_toolkits.py
index a7be59a940c5..a3eee4dea61a 100644
--- a/doc/sphinxext/mock_gui_toolkits.py
+++ b/doc/sphinxext/mock_gui_toolkits.py
@@ -6,23 +6,8 @@ class MyCairoCffi(MagicMock):
     __name__ = "cairocffi"
 
 
-class MyWX(MagicMock):
-    class Panel(object):
-        pass
-
-    class ToolBar(object):
-        pass
-
-    class Frame(object):
-        pass
-
-    class StatusBar(object):
-        pass
-
-
 def setup(app):
     sys.modules.update(
         cairocffi=MyCairoCffi(),
-        wx=MyWX(),
     )
     return {'parallel_read_safe': True, 'parallel_write_safe': True}