Handle shlex parse errors in query strings

Provide context: offending query string.
Update changelog.
Fix #1290.

beets/library.py

@@ -1069,7 +1069,10 @@ def parse_query_string(s, model_cls):
     # http://bugs.python.org/issue6988
     if isinstance(s, unicode):
         s = s.encode('utf8')
-    parts = [p.decode('utf8') for p in shlex.split(s)]
+    try:
+        parts = [p.decode('utf8') for p in shlex.split(s)]
+    except ValueError as exc:
+        raise ValueError("Cannot parse {0!r} (error was: {1})".format(s, exc))
     return parse_query_parts(parts, model_cls)
 
 

docs/changelog.rst

@@ -86,6 +86,7 @@ Fixes:
   like the bitrate. :bug:`1268`
 * The error message when MusicBrainz is not reachable on the network is now
   much clearer. Thanks to Tom Jaspers. :bug:`1190` :bug:`1272`
+* Improve error messages when parsing query strings with shlex. :bug:`1290`
 
 For developers: