Move font cache rebuild out of exception handler

Kojoley · Kojoley · commit 72444e6c53b2 · 2018-10-05T23:54:29.000+03:00
The purpose of the patch is to make tracebacks from cache rebuilding clearer.
diff --git a/lib/matplotlib/font_manager.py b/lib/matplotlib/font_manager.py
@@ -1356,17 +1356,20 @@ def _rebuild():
     if _fmcache:
         try:
             fontManager = json_load(_fmcache)
-            if (not hasattr(fontManager, '_version') or
-                fontManager._version != FontManager.__version__):
-                _rebuild()
-            else:
-                fontManager.default_size = None
-                _log.debug("Using fontManager instance from %s", _fmcache)
-        except TimeoutError:
-            raise
-        except Exception:
-            _rebuild()
-    else:
+        except FileNotFoundError:
+            _log.debug("No font cache found %s", _fmcache)
+        except json.JSONDecodeError:
+            _log.warning("Font cache parsing failed %s", _fmcache)
+
+        if (not hasattr(fontManager, '_version') or
+            fontManager._version != FontManager.__version__):
+            _log.debug("Font cache needs rebuild (version mismatch)")
+            fontManager = None
+        else:
+            fontManager.default_size = None
+            _log.debug("Using fontManager instance from %s", _fmcache)
+
+    if fontManager is None:
         _rebuild()
 
     def findfont(prop, **kw):
