actually fix projection from sub-queries

fixes #607 (for real this time)
RDFLib · Jan 20, 2017 · b1113d7 · b1113d7
1 parent 0f38e7d
commit b1113d7
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diff --git a/rdflib/plugins/sparql/algebra.py b/rdflib/plugins/sparql/algebra.py
@@ -643,6 +643,12 @@ def simplify(n):
 
 def analyse(n, children):
 
+    """
+    Some things can be lazily joined.
+    This propegates whether they can up the tree
+    and sets lazy flags for all joins
+    """
+
     if isinstance(n, CompValue):
         if n.name == 'Join':
             n["lazy"] = all(children)

diff --git a/rdflib/plugins/sparql/evaluate.py b/rdflib/plugins/sparql/evaluate.py
@@ -94,7 +94,7 @@ def evalLazyJoin(ctx, join):
     for a in evalPart(ctx, join.p1):
         c = ctx.thaw(a)
         for b in evalPart(c, join.p2):
-            yield b
+            yield b.merge(a) # merge, as some bindings may have been forgotten
 
 
 def evalJoin(ctx, join):

diff --git a/test/test_issue607.py b/test/test_issue607.py