Remove __doc__ from module's __all__

CHANGELOG.md

@@ -34,6 +34,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
   - `PyTypeObject_INIT` [#1429](https://github.com/PyO3/pyo3/pull/1429)
   - `PyObject_Check`, `PySuper_Check`, and `FreeFunc` [#1438](https://github.com/PyO3/pyo3/pull/1438)
 - Remove pyclass implementation details `Type`, `DESCRIPTION`, and `FLAGS` from `PyTypeInfo`. [#1456](https://github.com/PyO3/pyo3/pull/1456)
+- Remove `__doc__` from module's `__all__`. [#1509](https://github.com/PyO3/pyo3/pull/1509)
 
 ### Fixed
 - Remove FFI definition `PyCFunction_ClearFreeList` for Python 3.9 and later. [#1425](https://github.com/PyO3/pyo3/pull/1425)

src/derive_utils.rs

@@ -320,7 +320,7 @@ impl ModuleDef {
             return Err(crate::PyErr::fetch(py));
         }
         let module = py.from_owned_ptr_or_err::<PyModule>(module)?;
-        module.add("__doc__", doc)?;
+        module.setattr("__doc__", doc)?;
         initializer(py, module)?;
         Ok(crate::IntoPyPointer::into_ptr(module))
     }

tests/test_module.rs

@@ -226,6 +226,15 @@ fn test_module_dict() {
     py_assert!(py, module, "module.yay == 'me'");
 }
 
+#[test]
+fn test_module_dunder_all() {
+    let gil = Python::acquire_gil();
+    let py = gil.python();
+    let module = pyo3::wrap_pymodule!(foobar_module)(py);
+
+    py_assert!(py, module, "module.__all__ == ['foobar']");
+}
+
 #[pyfunction]
 fn subfunction() -> String {
     "Subfunction".to_string()