Allow '-1' (empty) in multilink expression

Author: schlatterbeck

roundup/backends/back_anydbm.py

@@ -77,6 +77,14 @@ def evaluate(self, v):
     def visit(self, visitor):
         visitor(self)
 
+class Empty(Unary):
+
+    def evaluate(self, v):
+        return not v
+
+    def visit(self, visitor):
+        visitor(self)
+
 class Not(Unary):
 
     def evaluate(self, v):
@@ -110,7 +118,8 @@ def compile_expression(opcodes):
     stack = []
     push, pop = stack.append, stack.pop
     for opcode in opcodes:
-        if   opcode == -2: push(Not(pop()))
+        if   opcode == -1: push(Empty(opcode))
+        elif opcode == -2: push(Not(pop()))
         elif opcode == -3: push(And(pop(), pop()))
         elif opcode == -4: push(Or(pop(), pop()))
         else:              push(Equals(opcode))

roundup/backends/rdbms_common.py

@@ -2373,7 +2373,7 @@ def getnodeids(self, retired=None):
         ids = [str(x[0]) for x in self.db.cursor.fetchall()]
         return ids
 
-    def _subselect(self, proptree):
+    def _subselect(self, proptree, parentname=None):
         """Create a subselect. This is factored out because some
            databases (hmm only one, so far) doesn't support subselects
            look for "I can't believe it's not a toy RDBMS" in the mysql
@@ -2382,6 +2382,9 @@ def _subselect(self, proptree):
         multilink_table = proptree.propclass.table_name
         nodeid_name     = proptree.propclass.nodeid_name
         linkid_name     = proptree.propclass.linkid_name
+        if parentname is None:
+            parentname = '_' + proptree.parent.classname
+
         w = ''
         if proptree.need_retired:
             w = ' where %s.__retired__=0'%(multilink_table)
@@ -2390,8 +2393,7 @@ def _subselect(self, proptree):
             tn2 = '_' + proptree.classname
             w = ', %s where %s.%s=%s.id and %s.__retired__=0'%(tn2,
                 tn1, linkid_name, tn2, tn2)
-        classname = proptree.parent.classname
-        return '_%s.id not in (select %s from %s%s)'%(classname, nodeid_name,
+        return '%s.id not in (select %s from %s%s)'%(parentname, nodeid_name,
             multilink_table, w)
 
     def _filter_multilink_expression_fallback(
@@ -2465,15 +2467,20 @@ def _filter_multilink_expression(self, proptree, v):
             atom = \
                 "%s IN(SELECT %s FROM %s WHERE %s=a.id)" % (
                 self.db.arg, lid, multilink_table, nid)
+            atom_nil = self._subselect(proptree, 'a')
+
+            lambda_atom = lambda n: atom if n.x >= 0 else atom_nil
 
             intron = \
                 "_%(classname)s.id in (SELECT id " \
                 "FROM _%(classname)s AS a WHERE %(condition)s) " % {
                     'classname' : classname,
-                    'condition' : expr.generate(lambda n: atom) }
+                    'condition' : expr.generate(lambda_atom) }
 
             values = []
-            def collect_values(n): values.append(n.x)
+            def collect_values(n):
+                if n.x >= 0:
+                    values.append(n.x)
             expr.visit(collect_values)
 
             return intron, values

test/db_test_base.py

@@ -1980,10 +1980,21 @@ def testFilteringMultilinkExpression(self):
             # '3' or empty (without explicit 'or')
             ae(filt(None, {kw: ['3', '-1']}),
                ['1', '2', '3'])
-            # This does not work with any of the backends currently:
             # '3' or empty (with explicit 'or')
-            #ae(filt(None, {kw: ['3', '-1', '-4']}),
-            #   ['1', '2', '3'])
+            ae(filt(None, {kw: ['3', '-1', '-4']}),
+               ['1', '2', '3'])
+            # empty or '3' (with explicit 'or')
+            ae(filt(None, {kw: ['-1', '3', '-4']}),
+               ['1', '2', '3'])
+            # '3' and empty (should always return empty list)
+            ae(filt(None, {kw: ['3', '-1', '-3']}),
+               [])
+            # empty and '3' (should always return empty list)
+            ae(filt(None, {kw: ['3', '-1', '-3']}),
+               [])
+            # ('4' and empty) or ('3' or empty)
+            ae(filt(None, {kw: ['4', '-1', '-3', '3', '-1', '-4', '-4']}),
+               ['1', '2', '3'])
 
     def testFilteringRevMultilink(self):
         ae, iiter = self.filteringSetupTransitiveSearch('user')
@@ -2047,6 +2058,7 @@ def testFilteringRevMultilinkExpression(self):
         # Retire users '9' and '10' to reduce list
         self.db.user.retire ('9')
         self.db.user.retire ('10')
+        self.db.commit ()
         for filt in iiter():
             # '1' or '2'
             ae(filt(None, {ni: ['1', '2', '-4']}), ['4', '5'])
@@ -2058,6 +2070,19 @@ def testFilteringRevMultilinkExpression(self):
             ae(filt(None, {ni: ['6', '1', '-2', '-3']}), ['3', '5'])
             # '2' or empty (implicit or)
             ae(filt(None, {ni: ['-1', '2']}), ['1', '2', '5', '6', '7', '8'])
+            # '2' or empty (explicit or)
+            ae(filt(None, {ni: ['-1', '2', '-4']}),
+               ['1', '2', '5', '6', '7', '8'])
+            # empty or '2' (explicit or)
+            ae(filt(None, {ni: ['2', '-1', '-4']}),
+               ['1', '2', '5', '6', '7', '8'])
+            # '2' and empty (should always return empty list)
+            ae(filt(None, {ni: ['-1', '2', '-3']}), [])
+            # empty and '2' (should always return empty list)
+            ae(filt(None, {ni: ['2', '-1', '-3']}), [])
+            # ('4' and empty) or ('2' or empty)
+            ae(filt(None, {ni: ['4', '-1', '-3', '2', '-1', '-4', '-4']}),
+               ['1', '2', '5', '6', '7', '8'])
 
     def testFilteringMany(self):
         ae, iiter = self.filteringSetup()