Make FontManager.score_weight less lenient.

anntzer · anntzer · commit de67128045ae · 2018-10-19T15:12:28.000+02:00
diff --git a/doc/api/next_api_changes/2018-10-19-AL.rst b/doc/api/next_api_changes/2018-10-19-AL.rst
@@ -0,0 +1,11 @@
+`FontManager.score_weight` is more strict with its inputs
+`````````````````````````````````````````````````````````
+
+Previously, when a weight string was passed to `FontManager.score_weight`,
+
+- if the weight was the string representation of an integer, it would be
+  converted to that integer,
+- otherwise, if the weight was not a standard weight name, it would be silently
+  replaced by a value of 500 ("normal" weight).
+
+`FontManager.score_weight` now raises an exception on such inputs.
diff --git a/lib/matplotlib/font_manager.py b/lib/matplotlib/font_manager.py
@@ -33,6 +33,7 @@
 from functools import lru_cache
 import json
 import logging
+from numbers import Number
 import os
 from pathlib import Path
 import subprocess
@@ -1066,8 +1067,8 @@ def score_style(self, style1, style2):
         """
         if style1 == style2:
             return 0.0
-        elif style1 in ('italic', 'oblique') and \
-                style2 in ('italic', 'oblique'):
+        elif (style1 in ('italic', 'oblique')
+              and style2 in ('italic', 'oblique')):
             return 0.1
         return 1.0
 
@@ -1111,21 +1112,12 @@ def score_weight(self, weight1, weight2):
         the CSS numeric values of *weight1* and *weight2*, normalized between
         0.05 and 1.0.
         """
-
         # exact match of the weight names, e.g. weight1 == weight2 == "regular"
-        if (isinstance(weight1, str) and
-                isinstance(weight2, str) and
-                weight1 == weight2):
+        if cbook._str_equal(weight1, weight2):
             return 0.0
-        try:
-            weightval1 = int(weight1)
-        except ValueError:
-            weightval1 = weight_dict.get(weight1, 500)
-        try:
-            weightval2 = int(weight2)
-        except ValueError:
-            weightval2 = weight_dict.get(weight2, 500)
-        return 0.95*(abs(weightval1 - weightval2) / 1000.0) + 0.05
+        w1 = weight1 if isinstance(weight1, Number) else weight_dict[weight1]
+        w2 = weight2 if isinstance(weight2, Number) else weight_dict[weight2]
+        return 0.95 * (abs(w1 - w2) / 1000) + 0.05
 
     def score_size(self, size1, size2):
         """
