Fix for when no afm files are installed. From https://bugzilla.redhat.com/show_bug.cgi?id=896182, though fixed in a different way.

mdboom · mdboom · commit e87722398538 · 2013-01-25T13:24:10.000-05:00
diff --git a/lib/matplotlib/font_manager.py b/lib/matplotlib/font_manager.py
@@ -997,7 +997,10 @@ def __init__(self, size=None, weight='normal'):
         self.afmfiles = findSystemFonts(paths, fontext='afm') + \
             findSystemFonts(fontext='afm')
         self.afmlist = createFontList(self.afmfiles, fontext='afm')
-        self.defaultFont['afm'] = self.afmfiles[0]
+        if len(self.afmfiles):
+            self.defaultFont['afm'] = self.afmfiles[0]
+        else:
+            self.defaultFont['afm'] = None
 
         self.ttf_lookup_cache = {}
         self.afm_lookup_cache = {}
