[Backport maintenance/2.15.x] Make sys.argv uninferable because it …

…never is (#2244) (#2297)

* 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

(cherry picked from commit ea78827)
Co-authored-by: Pierre Sassoulas <pierre.sassoulas@gmail.com>

astroid/inference.py

@@ -369,7 +369,12 @@ def infer_attribute(
                 context.constraints[self.attrname] = constraint.get_constraints(
                     self, frame=frame
                 )
-            yield from owner.igetattr(self.attrname, context)
+            if self.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(self.attrname, context)
         except (
             AttributeInferenceError,
             InferenceError,

tests/test_inference.py

@@ -7102,3 +7102,18 @@ 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 util.Uninferable