Make sys.argv uninferable because it never is (#2244)

It's impossible to infer the value it will have outside of static analysis where it's our own value.

See pylint-dev/pylint#7710

Author: Pierre-Sassoulas

astroid/nodes/node_classes.py

@@ -1099,7 +1099,12 @@ def _infer_attribute(
             if isinstance(owner, (ClassDef, Instance)):
                 frame = owner if isinstance(owner, ClassDef) else owner._proxied
                 context.constraints[node.attrname] = get_constraints(node, frame=frame)
-            yield from owner.igetattr(node.attrname, context)
+            if node.attrname == "argv" and owner.name == "sys":
+                # sys.argv will never be inferable during static analysis
+                # It's value would be the args passed to the linter itself
+                yield util.Uninferable
+            else:
+                yield from owner.igetattr(node.attrname, context)
         except (
             AttributeInferenceError,
             InferenceError,

tests/test_inference.py

@@ -7238,3 +7238,18 @@ def test_old_style_string_formatting_with_specs(self) -> None:
         inferred = next(node.infer())
         assert isinstance(inferred, nodes.Const)
         assert inferred.value == "My name is Daniel, I'm 12.00"
+
+
+def test_sys_argv_uninferable() -> None:
+    """Regression test for https://github.com/pylint-dev/pylint/issues/7710."""
+    a: nodes.List = extract_node(
+        textwrap.dedent(
+            """
+    import sys
+
+    sys.argv"""
+        )
+    )
+    sys_argv_value = list(a._infer())
+    assert len(sys_argv_value) == 1
+    assert sys_argv_value[0] is Uninferable