From 01a0a7ac2e070ee165e960bb9f2456dbbc7411ab Mon Sep 17 00:00:00 2001
From: Stanislav Levin <slev@altlinux.org>
Date: Sun, 22 Dec 2019 23:08:47 +0300
Subject: [PATCH] Make use of cache while transform builtin containers

As of now, the transformation of builtin containers which
members, in turn, are containers relies on `safe_infer`
helper. `safe_infer` tries to infer the node to get its
values. Doing this without a cache containing a previously
inferred nodes lead to infinite recursion, for example, on
resolving a class attribute.

Note: this doesn't help to infer a class attribute by itself
is such a case, but prevents crash.

Closes: https://github.com/PyCQA/pylint/issues/3245
Signed-off-by: Stanislav Levin <slev@altlinux.org>
---
 astroid/brain/brain_builtin_inference.py |  9 ++++++---
 tests/unittest_inference.py              | 14 ++++++++++++++
 2 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/astroid/brain/brain_builtin_inference.py b/astroid/brain/brain_builtin_inference.py
index 7cc6095fd1..3cbe48f715 100644
--- a/astroid/brain/brain_builtin_inference.py
+++ b/astroid/brain/brain_builtin_inference.py
@@ -154,7 +154,7 @@ def _container_generic_inference(node, context, node_type, transform):
     if len(node.args) > 1:
         raise UseInferenceDefault()
 
-    arg, = args
+    (arg,) = args
     transformed = transform(arg)
     if not transformed:
         try:
@@ -169,7 +169,7 @@ def _container_generic_inference(node, context, node_type, transform):
     return transformed
 
 
-def _container_generic_transform(arg, klass, iterables, build_elts):
+def _container_generic_transform(arg, context, klass, iterables, build_elts):
     if isinstance(arg, klass):
         return arg
     elif isinstance(arg, iterables):
@@ -177,7 +177,9 @@ def _container_generic_transform(arg, klass, iterables, build_elts):
             elts = [elt.value for elt in arg.elts]
         else:
             # TODO: Does not handle deduplication for sets.
-            elts = filter(None, map(helpers.safe_infer, arg.elts))
+            elts = filter(
+                None, map(partial(helpers.safe_infer, context=context), arg.elts)
+            )
     elif isinstance(arg, nodes.Dict):
         # Dicts need to have consts as strings already.
         if not all(isinstance(elt[0], nodes.Const) for elt in arg.items):
@@ -197,6 +199,7 @@ def _infer_builtin_container(
 ):
     transform_func = partial(
         _container_generic_transform,
+        context=context,
         klass=klass,
         iterables=iterables,
         build_elts=build_elts,
diff --git a/tests/unittest_inference.py b/tests/unittest_inference.py
index a54c4ee159..a5ed96b1da 100644
--- a/tests/unittest_inference.py
+++ b/tests/unittest_inference.py
@@ -5502,5 +5502,19 @@ class A:
     assert inferred.value == 42
 
 
+def test_recursion_error_inferring_builtin_containers():
+    node = extract_node(
+        """
+    class Foo:
+        a = "foo"
+    inst = Foo()
+
+    b = tuple([inst.a]) #@
+    inst.a = b
+    """
+    )
+    helpers.safe_infer(node.targets[0])
+
+
 if __name__ == "__main__":
     unittest.main()