Merge pull request #126 from potassco/63-bug-predicate_order-for-quer…

…ies-with-multiple-joins

Bug fix for predicate order for queries with a function/lambda select clause

clorm/orm/query.py

@@ -3415,7 +3415,7 @@ def make_query(qp, factsets, factindexes):
 # ------------------------------------------------------------------------------
 
 
-def make_outputter(insig, outsig):
+def make_outputter(queryroots, insig, outsig):
     def make_simple_outputter():
         af = make_input_alignment_functor(insig, outsig)
         return lambda intuple, af=af: af(intuple)
@@ -3432,7 +3432,8 @@ def make_complex_outputter():
                 tmp = make_input_alignment_functor(insig, out.paths)
                 metasig.append(lambda x, af=tmp, f=out.functor: f(*af(x)))
             elif callable(out):
-                metasig.append(lambda x, f=out: f(*x))
+                tmp = make_input_alignment_functor(insig, queryroots)
+                metasig.append(lambda x, af=tmp, f=out: f(*af(x)))
             else:
                 metasign.append(lambda x, out=out: out)
 
@@ -4232,10 +4233,11 @@ def all(self) -> Generator[Any, None, None]:
         (self._qplan, self._query) = self._make_plan_and_query()
 
         outsig = self._qspec.select
+        roots = self._qspec.roots
         if outsig is None or not outsig:
             outsig = self._qspec.roots
 
-        self._outputter = make_outputter(self._qplan.output_signature, outsig)
+        self._outputter = make_outputter(roots, self._qplan.output_signature, outsig)
         self._unwrap = not self._qspec.tuple and len(outsig) == 1
         self._distinct = self._qspec.distinct
 
@@ -4387,9 +4389,10 @@ def execute_fn(facts):
             )
 
         outsig = self._qspec.select
+        roots = self._qspec.roots
         if outsig is None or not outsig:
             outsig = self._qspec.roots
-        self._outputter = make_outputter(self._qplan.output_signature, outsig)
+        self._outputter = make_outputter(roots, self._qplan.output_signature, outsig)
         self._unwrap = False
         self._distinct = self._qspec.distinct
 

tests/test_orm_query.py

@@ -2593,9 +2593,11 @@ def f_in_factmaps(f, factmaps):
     return f in fm.factset
 
 
-def factmaps_dict(facts, indexes=[]):
+def factmaps_dict(facts, indexes=None):
     from itertools import groupby
 
+    if indexes is None:
+        indexes = []
     indexes = sorted([hashable_path(p) for p in indexes])
     predicate2indexes = {}
     for k, g in groupby(indexes, lambda p: path(p).meta.predicate):
@@ -3431,6 +3433,57 @@ def replace(subroots, fn):
         self.assertTrue(f_in_factmaps(F(35, "a"), factmaps))
         self.assertTrue(f_in_factmaps(F(35, "foo"), factmaps))
 
+    # ----------------------------------------------------------------------------------------
+    # Test the output order of the predicates for a complex join matches the input order. This
+    # is to track down a bug that is not re-aligning the order when the query execution plan
+    # internally changes the order.
+    #
+    # NOTE: the original bug is to do with passing a function/lambda to the "select" clause.
+    # Internally since no input signature is associated with the function/lambda it should be
+    # given the signature of the query roots. This wasn't happening and was instead being
+    # passed the inputs as they were generated by the query plan. The fix is to use the query
+    # root as the input signature for a function/lambda.
+    # ----------------------------------------------------------------------------------------
+    def test_api_QueryExecutor_output_alignment(self):
+        class F(Predicate):
+            aint = IntegerField
+
+        class G(Predicate):
+            astr = StringField
+
+        class H(Predicate):
+            aint = IntegerField
+            astr = StringField
+
+        pw = process_where
+        pj = process_join
+        roots = [F, H, G]
+
+        factmaps = factmaps_dict(
+            [F(1), F(2), G("a"), G("b"), H(1, "a"), H(2, "b")], [G.astr, F.aint, H.astr]
+        )
+
+        qspec = QuerySpec(
+            roots=roots,
+            join=pj([F.aint == H.aint, G.astr == H.astr], roots),
+            where=pw(F.aint == 1, roots),
+            select=(lambda f, h, g: (f, h, g),),
+        )
+
+        qe = QueryExecutor(factmaps, qspec)
+        plan, _ = qe._make_plan_and_query()
+        plan_roots = [x.root.meta.predicate for x in plan]
+
+        # To check that the bug is fixed and the order of the output is the same as the input
+        # we need to make sure the order of the input roots is different to the plan roots.
+        self.assertNotEqual(roots, plan_roots)
+        output = list(qe.all())
+        self.assertEqual(len(output), 1)
+        f, h, g = output[0]
+        self.assertEqual(type(f), F)
+        self.assertEqual(type(g), G)
+        self.assertEqual(type(h), H)
+
 
 # ------------------------------------------------------------------------------
 # main