Use safe_infer in _unpack_args and _unpack_keywords (#2117)

ChangeLog

@@ -52,6 +52,10 @@ Release date: TBA
 
 * Remove dependency on ``wrapt``.
 
+* ``CallSite._unpack_args`` and ``CallSite._unpack_keywords`` now use ``safe_infer()`` for
+  better inference and fewer false positives.
+
+  Closes pylint-dev/pylint#8544
 
 What's New in astroid 2.15.3?
 =============================

astroid/arguments.py

@@ -8,6 +8,7 @@
 from astroid.bases import Instance
 from astroid.context import CallContext, InferenceContext
 from astroid.exceptions import InferenceError, NoDefault
+from astroid.helpers import safe_infer
 from astroid.util import Uninferable, UninferableBase
 
 
@@ -91,27 +92,14 @@ def _unpack_keywords(self, keywords, context: InferenceContext | None = None):
         for name, value in keywords:
             if name is None:
                 # Then it's an unpacking operation (**)
-                try:
-                    inferred = next(value.infer(context=context))
-                except InferenceError:
-                    values[name] = Uninferable
-                    continue
-                except StopIteration:
-                    continue
-
+                inferred = safe_infer(value, context=context)
                 if not isinstance(inferred, nodes.Dict):
                     # Not something we can work with.
                     values[name] = Uninferable
                     continue
 
                 for dict_key, dict_value in inferred.items:
-                    try:
-                        dict_key = next(dict_key.infer(context=context))
-                    except InferenceError:
-                        values[name] = Uninferable
-                        continue
-                    except StopIteration:
-                        continue
+                    dict_key = safe_infer(dict_key, context=context)
                     if not isinstance(dict_key, nodes.Const):
                         values[name] = Uninferable
                         continue
@@ -134,14 +122,7 @@ def _unpack_args(self, args, context: InferenceContext | None = None):
         context.extra_context = self.argument_context_map
         for arg in args:
             if isinstance(arg, nodes.Starred):
-                try:
-                    inferred = next(arg.value.infer(context=context))
-                except InferenceError:
-                    values.append(Uninferable)
-                    continue
-                except StopIteration:
-                    continue
-
+                inferred = safe_infer(arg.value, context=context)
                 if isinstance(inferred, UninferableBase):
                     values.append(Uninferable)
                     continue

tests/test_inference.py

@@ -17,13 +17,22 @@
 
 import pytest
 
-from astroid import Slice, arguments, helpers, nodes, objects, test_utils, util
+from astroid import (
+    Slice,
+    Uninferable,
+    arguments,
+    helpers,
+    nodes,
+    objects,
+    test_utils,
+    util,
+)
 from astroid import decorators as decoratorsmod
 from astroid.arguments import CallSite
 from astroid.bases import BoundMethod, Instance, UnboundMethod, UnionType
 from astroid.builder import AstroidBuilder, _extract_single_node, extract_node, parse
 from astroid.const import PY38_PLUS, PY39_PLUS, PY310_PLUS
-from astroid.context import InferenceContext
+from astroid.context import CallContext, InferenceContext
 from astroid.exceptions import (
     AstroidTypeError,
     AttributeInferenceError,
@@ -1443,10 +1452,9 @@ def get_context_data(self, **kwargs):
         """
         node = extract_node(code)
         assert isinstance(node, nodes.NodeNG)
-        result = node.inferred()
-        assert len(result) == 2
-        assert isinstance(result[0], nodes.Dict)
-        assert result[1] is util.Uninferable
+        results = node.inferred()
+        assert len(results) == 2
+        assert all(isinstance(result, nodes.Dict) for result in results)
 
     def test_python25_no_relative_import(self) -> None:
         ast = resources.build_file("data/package/absimport.py")
@@ -5296,6 +5304,41 @@ def test_duplicated_keyword_arguments(self) -> None:
         site = self._call_site_from_call(ast_node)
         self.assertIn("f", site.duplicated_keywords)
 
+    def test_call_site_uninferable(self) -> None:
+        code = """
+            def get_nums():
+                nums = ()
+                if x == '1':
+                    nums = (1, 2)
+                return nums
+
+            def add(x, y):
+                return x + y
+
+            nums = get_nums()
+
+            if x:
+                kwargs = {1: bar}
+            else:
+                kwargs = {}
+
+            if nums:
+                add(*nums)
+                print(**kwargs)
+        """
+        # Test that `*nums` argument should be Uninferable
+        ast = parse(code, __name__)
+        *_, add_call, print_call = list(ast.nodes_of_class(nodes.Call))
+        nums_arg = add_call.args[0]
+        add_call_site = self._call_site_from_call(add_call)
+        self.assertEqual(add_call_site._unpack_args([nums_arg]), [Uninferable])
+
+        print_call_site = self._call_site_from_call(print_call)
+        keywords = CallContext(print_call.args, print_call.keywords).keywords
+        self.assertEqual(
+            print_call_site._unpack_keywords(keywords), {None: Uninferable}
+        )
+
 
 class ObjectDunderNewTest(unittest.TestCase):
     def test_object_dunder_new_is_inferred_if_decorator(self) -> None: