Fixed typed variable positional/keyword arguments causing compilation…

… errors on Python < 3.9 Fixes #330.
agronholm · Apr 8, 2023 · f5cf181 · f5cf181
1 parent bfbfc52
commit f5cf181
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Showing 4 changed files with 55 additions and 18 deletions.
diff --git a/docs/versionhistory.rst b/docs/versionhistory.rst
@@ -8,6 +8,8 @@ This library adheres to `Semantic Versioning 2.0 <https://semver.org/#semantic-v
 - The ``.pyc`` files now use a version-based optimization suffix in the file names so as
   not to cause the interpreter to load potentially faulty/incompatible cached bytecode
   generated by older versions
+- Fixed typed variable positional and keyword arguments causing compilation errors on
+  Python 3.7 and 3.8
 
 **4.0.0rc1** (2023-04-02)
 

diff --git a/src/typeguard/_transformer.py b/src/typeguard/_transformer.py
@@ -604,35 +604,39 @@ def visit_FunctionDef(
                     else:
                         container = self._get_import("typing", "Tuple")
 
-                    arg_annotations[node.args.vararg.arg] = Subscript(
-                        container,
-                        Tuple(
-                            [
-                                self._convert_annotation(node.args.vararg.annotation),
-                                Constant(Ellipsis),
-                            ],
-                            ctx=Load(),
-                        ),
+                    subscript_slice: Tuple | Index = Tuple(
+                        [
+                            self._convert_annotation(node.args.vararg.annotation),
+                            Constant(Ellipsis),
+                        ],
                         ctx=Load(),
                     )
+                    if sys.version_info < (3, 9):
+                        subscript_slice = Index(subscript_slice, ctx=Load())
+
+                    arg_annotations[node.args.vararg.arg] = Subscript(
+                        container, subscript_slice, ctx=Load()
+                    )
 
                 if node.args.kwarg and node.args.kwarg.annotation:
                     if sys.version_info >= (3, 9):
                         container = Name("dict", ctx=Load())
                     else:
                         container = self._get_import("typing", "Dict")
 
-                    arg_annotations[node.args.kwarg.arg] = Subscript(
-                        container,
-                        Tuple(
-                            [
-                                Name("str", ctx=Load()),
-                                self._convert_annotation(node.args.kwarg.annotation),
-                            ],
-                            ctx=Load(),
-                        ),
+                    subscript_slice = Tuple(
+                        [
+                            Name("str", ctx=Load()),
+                            self._convert_annotation(node.args.kwarg.annotation),
+                        ],
                         ctx=Load(),
                     )
+                    if sys.version_info < (3, 9):
+                        subscript_slice = Index(subscript_slice, ctx=Load())
+
+                    arg_annotations[node.args.kwarg.arg] = Subscript(
+                        container, subscript_slice, ctx=Load()
+                    )
 
                 if arg_annotations:
                     self._memo.variable_annotations.update(arg_annotations)

diff --git a/tests/dummymodule.py b/tests/dummymodule.py
@@ -5,6 +5,7 @@
     Any,
     AsyncGenerator,
     Callable,
+    Dict,
     Generator,
     List,
     Sequence,
@@ -298,3 +299,10 @@ class Inner:
         @typechecked
         def override_typecheck_fail_callback(self, value: int) -> None:
             pass
+
+
+@typechecked
+def typed_variable_args(
+    *args: str, **kwargs: int
+) -> Tuple[Tuple[str, ...], Dict[str, int]]:
+    return args, kwargs
diff --git a/tests/test_instrumentation.py b/tests/test_instrumentation.py
@@ -307,3 +307,26 @@ def test_outer_class_typecheck_fail_callback(self, dummymodule, capsys):
     def test_inner_class_no_overrides(self, dummymodule):
         with pytest.raises(TypeCheckError):
             dummymodule.OverrideClass.Inner().override_typecheck_fail_callback("foo")
+
+
+class TestVariableArguments:
+    def test_success(self, dummymodule):
+        assert dummymodule.typed_variable_args("foo", "bar", a=1, b=8) == (
+            ("foo", "bar"),
+            {"a": 1, "b": 8},
+        )
+
+    def test_args_fail(self, dummymodule):
+        with pytest.raises(
+            TypeCheckError,
+            match=r'item 0 of argument "args" \(tuple\) is not an instance of str',
+        ):
+            dummymodule.typed_variable_args(1, a=1, b=8)
+
+    def test_kwargs_fail(self, dummymodule):
+        with pytest.raises(
+            TypeCheckError,
+            match=r'value of key \'a\' of argument "kwargs" \(dict\) is not an '
+            r"instance of int",
+        ):
+            dummymodule.typed_variable_args("foo", "bar", a="baz")