[GR-10385] zip iter

PullRequest: graalpython/79

Author: cosminbasca

graalpython/com.oracle.graal.python.test/src/tests/test_iterator.py

@@ -96,3 +96,7 @@ def test_iter():
     zip_iterator = type(iter(zip()))
     assert str(zip_iterator) == "<class 'zip'>"
     # <class 'zip'>
+
+
+def test_zip_no_args():
+    assert list(zip(*[])) == []

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/objects/iterator/PZipBuiltins.java

@@ -36,6 +36,7 @@
 import com.oracle.graal.python.nodes.control.GetNextNode;
 import com.oracle.graal.python.nodes.function.PythonBuiltinNode;
 import com.oracle.graal.python.nodes.function.builtins.PythonUnaryBuiltinNode;
+import com.oracle.graal.python.runtime.exception.PythonErrorType;
 import com.oracle.truffle.api.dsl.Cached;
 import com.oracle.truffle.api.dsl.GenerateNodeFactory;
 import com.oracle.truffle.api.dsl.NodeFactory;
@@ -53,6 +54,11 @@ protected List<? extends NodeFactory<? extends PythonBuiltinNode>> getNodeFactor
     @GenerateNodeFactory
     public abstract static class NextNode extends PythonUnaryBuiltinNode {
 
+        @Specialization(guards = "isEmpty(self.getIterators())")
+        public Object __next__(@SuppressWarnings("unused") PZip self) {
+            throw raise(PythonErrorType.StopIteration);
+        }
+
         @Specialization
         public Object __next__(PZip self,
                         @Cached("create()") GetNextNode next) {