strip null characters from MB queries (#142)

NEWS

@@ -20,6 +20,7 @@
   copies afterward). This is fixed.
 * Fix a bug where some files would be erroneously interpreted as MP4.
 * Fix permission bits applied to album art files.
+* Fix malformed MusicBrainz queries caused by null characters.
 * The old "albumify" plugin for upgrading databases was removed.
 
 1.0b6

beets/autotag/mb.py

@@ -127,7 +127,8 @@ def _lucene_escape(text):
     string.
     """
     # Regex stolen from MusicBrainz Picard.
-    return re.sub(r'([+\-&|!(){}\[\]\^"~*?:\\])', r'\\\1', text)
+    out = re.sub(r'([+\-&|!(){}\[\]\^"~*?:\\])', r'\\\1', text)
+    return out.replace('\x00', '')
 
 def find_releases(criteria, limit=SEARCH_LIMIT):
     """Get a list of release dictionaries from the MusicBrainz

test/test_mb.py

@@ -146,6 +146,15 @@ class MBReleaseDictTest(unittest.TestCase):
         d = mb.release_dict(release)
         self.assertTrue(d['va'])
 
+class QuerySanitationTest(unittest.TestCase):
+    def test_special_char_escaped(self):
+        res = mb._lucene_escape('!')
+        self.assertEqual(res, '\\!')
+
+    def test_null_character_removed(self):
+        res = mb._lucene_escape('\0')
+        self.assertEqual(res, '')
+
 def suite():
     return unittest.TestLoader().loadTestsFromName(__name__)