Don't emit not-iterating warnings when the builtin is used in an unpacking.

2 files changed, 24 insertions, 0 deletions

diff --git a/pylint/checkers/python3.py b/pylint/checkers/python3.py
index e708c4a..a60d0de 100644
--- a/pylint/checkers/python3.py
+++ b/pylint/checkers/python3.py
@@ -78,6 +78,12 @@ def _in_iterating_context(node):
         elif isinstance(parent.func, astroid.Getattr):
             if parent.func.attrname == 'join':
                 return True
+    # If the call is in an unpacking, there's no need to warn,
+    # since it can be considered iterating.
+    elif (isinstance(parent, astroid.Assign) and
+          isinstance(parent.targets[0], (astroid.List, astroid.Tuple))):
+        if len(parent.targets[0].elts) > 1:
+            return True
     return False
 
 
diff --git a/pylint/test/unittest_checker_python3.py b/pylint/test/unittest_checker_python3.py
index 2407fc5..825e827 100644
--- a/pylint/test/unittest_checker_python3.py
+++ b/pylint/test/unittest_checker_python3.py
@@ -139,6 +139,22 @@ class Python3CheckerTest(testutils.CheckerTestCase):
         with self.assertNoMessages():
             self.walk(module)
 
+    def as_iterable_in_unpacking(self, fxn):
+        node = test_utils.extract_node("""
+        a, b = __({}())
+        """.format(fxn))
+        with self.assertNoMessages():
+            self.checker.visit_callfunc(node)
+
+    def as_assignment(self, fxn):
+        checker = '{}-builtin-not-iterating'.format(fxn)
+        node = test_utils.extract_node("""
+        a = __({}())
+        """.format(fxn))
+        message = testutils.Message(checker, node=node)
+        with self.assertAddsMessages(message):
+            self.checker.visit_callfunc(node)
+
     def iterating_context_tests(self, fxn):
         """Helper for verifying a function isn't used as an iterator."""
         self.as_iterable_in_for_loop_test(fxn)
@@ -149,6 +165,8 @@ class Python3CheckerTest(testutils.CheckerTestCase):
         self.as_used_in_variant_in_listcomp_test(fxn)
         self.as_argument_to_random_fxn_test(fxn)
         self.as_argument_to_str_join_test(fxn)
+        self.as_iterable_in_unpacking(fxn)
+        self.as_assignment(fxn)
 
         for func in ('iter', 'list', 'tuple', 'sorted',
                      'set', 'sum', 'any', 'all',