Catch UnicodeDecodeError while parsing config files

src/flake8/options/config.py

@@ -60,13 +60,21 @@ def __init__(self, program_name, args, extra_config_files):
     @staticmethod
     def _read_config(files):
         config = configparser.RawConfigParser()
-        try:
-            found_files = config.read(files)
-        except configparser.ParsingError:
-            LOG.exception("There was an error trying to parse a config "
-                          "file. The files we were attempting to parse "
-                          "were: %r", files)
-            found_files = []
+        if isinstance(files, (str, type(u''))):
+            files = [files]
+
+        found_files = []
+        for filename in files:
+            try:
+                found_files.extend(config.read(filename))
+            except UnicodeDecodeError:
+                LOG.exception("There was an error decoding a config file."
+                              "The file with a problem was %s.",
+                              filename)
+            except configparser.ParsingError:
+                LOG.exception("There was an error trying to parse a config "
+                              "file. The file with a problem was %s.",
+                              filename)
         return (config, found_files)
 
     def cli_config(self, files):

tests/unit/test_config_file_finder.py

@@ -1,3 +1,4 @@
+# -*- coding: utf-8 -*-
 """Tests for the ConfigFileFinder."""
 import configparser
 import os
@@ -135,4 +136,14 @@ def test_local_configs_double_read():
 ])
 def test_read_config_catches_broken_config_files(files):
     """Verify that we do not allow the exception to bubble up."""
-    assert config.ConfigFileFinder._read_config(files)[1] == []
+    _, parsed = config.ConfigFileFinder._read_config(files)
+    assert BROKEN_CONFIG_PATH not in parsed
+
+
+def test_read_config_catches_decoding_errors(tmpdir):
+    """Verify that we do not allow the exception to bubble up."""
+    setup_cfg = tmpdir.join('setup.cfg')
+    # pick an encoding that's unlikely to be a default
+    setup_cfg.write_binary(u'[x]\ny = €'.encode('cp1252'))
+    _, parsed = config.ConfigFileFinder._read_config(setup_cfg.strpath)
+    assert parsed == []