Bug-fix in expression parser

Tried to get minimum of an empty list. Add a test for this.

Author: schlatterbeck

roundup/hyperdb.py

@@ -802,7 +802,8 @@ def set_val(self, val, force=False, result=True):
                     self.val = list(vals)
                 else:
                     assert self.cls
-                    is_expression = min(int(i) for i in self.val) < -1
+                    is_expression = \
+                        self.val and min(int(i) for i in self.val) < -1
                     if is_expression:
                         # Tag on the ORed values with an AND
                         l = val

test/db_test_base.py

@@ -1852,7 +1852,9 @@ def testFilteringLink(self):
         grp = (None, None)
         for filt in iiter():
             ae(filt(None, {'status': '1'}, ('+','id'), grp), ['2','3'])
+            ae(filt(None, {'status': [], 'status.name': 'unread'}), [])
             ae(filt(None, {a: '-1'}, ('+','id'), grp), ['3','4'])
+            ae(filt(None, {a: []}, ('+','id'), grp), ['3','4'])
             ae(filt(None, {a: None}, ('+','id'), grp), ['3','4'])
             ae(filt(None, {a: [None]}, ('+','id'), grp), ['3','4'])
             ae(filt(None, {a: ['-1', None]}, ('+','id'), grp), ['3','4'])