Delay the fc-list warning by 5 seconds

astrofrog · astrofrog · commit 4f1ca3fa07de · 2016-11-29T20:28:00.000Z
diff --git a/lib/matplotlib/font_manager.py b/lib/matplotlib/font_manager.py
@@ -273,11 +273,17 @@ def get_fontconfig_fonts(fontext='ttf'):
 
     fontfiles = {}
     try:
-        warnings.warn('Matplotlib is building the font cache using fc-list. This may take a moment.')
         pipe = subprocess.Popen(['fc-list', '--format=%{file}\\n'],
                                 stdout=subprocess.PIPE,
                                 stderr=subprocess.PIPE)
-        output = pipe.communicate()[0]
+        # We emit a warning if the process has not completed after 5 seconds.
+        # We avoid showing it before since if this takes < 5 seconds, the user
+        # probably won't notice.
+        try:
+            output = pipe.communicate(timeout=5)[0]
+        except subprocess.Timeout:
+            warnings.warn('Matplotlib is building the font cache using fc-list. This may take a moment.')
+            output = pipe.communicate()[0]
     except (OSError, IOError):
         # Calling fc-list did not work, so we'll just return nothing
         return fontfiles
