Add deprecated_function/deprecated_member child classes

+ shortcut for different default messages

Co-authored-by: Justin Carpentier <justin.carpentier@inria.fr>

include/eigenpy/deprecation-policy.hpp

 //
+// Copyright (C) 2020 INRIA
 // Copyright (C) 2024 LAAS-CNRS, INRIA
 //
 #ifndef __eigenpy_deprecation_hpp__
@@ -23,11 +24,6 @@ constexpr PyObject *deprecationTypeToPyObj(DeprecationType dep) {
 
 }  // namespace detail
 
-constexpr char defaultDeprecationMessage[] =
-    "This function or attribute has been marked as deprecated, and will be "
-    "removed in the "
-    "future.";
-
 /// @brief A Boost.Python call policy which triggers a Python warning on
 /// precall.
 template <DeprecationType deprecation_type = DeprecationType::DEPRECATION,
@@ -36,11 +32,10 @@ struct deprecation_warning_policy : BasePolicy {
   using result_converter = typename BasePolicy::result_converter;
   using argument_package = typename BasePolicy::argument_package;
 
-  deprecation_warning_policy(
-      const std::string &warning_msg = defaultDeprecationMessage)
+  deprecation_warning_policy(const std::string &warning_msg)
       : BasePolicy(), m_what(warning_msg) {}
 
-  const std::string what() const { return m_what; }
+  std::string what() const { return m_what; }
 
   const BasePolicy *derived() const {
     return static_cast<const BasePolicy *>(this);
@@ -53,10 +48,34 @@ struct deprecation_warning_policy : BasePolicy {
     return derived()->precall(args);
   }
 
- private:
+ protected:
   const std::string m_what;
 };
 
+template <DeprecationType deprecation_type = DeprecationType::DEPRECATION,
+          class BasePolicy = bp::default_call_policies>
+struct deprecated_function
+    : deprecation_warning_policy<deprecation_type, BasePolicy> {
+  static constexpr char defaultMsg[] =
+      "This function has been marked as deprecated, and will be "
+      "removed in the future.";
+
+  deprecated_function(const std::string &msg = defaultMsg)
+      : deprecation_warning_policy<deprecation_type, BasePolicy>(msg) {}
+};
+
+template <DeprecationType deprecation_type = DeprecationType::DEPRECATION,
+          class BasePolicy = bp::default_call_policies>
+struct deprecated_member
+    : deprecation_warning_policy<deprecation_type, BasePolicy> {
+  static constexpr char defaultMsg[] =
+      "This attribute or method has been marked as deprecated, and will be "
+      "removed in the future.";
+
+  deprecated_member(const std::string &msg = defaultMsg)
+      : deprecation_warning_policy<deprecation_type, BasePolicy>(msg) {}
+};
+
 }  // namespace eigenpy
 
 #endif  // ifndef __eigenpy_deprecation_hpp__

unittest/deprecation_policy.cpp

@@ -16,9 +16,18 @@ void some_future_deprecated_function() {
       << std::endl;
 }
 
+class X {
+ public:
+  void deprecated_member_function() {}
+};
+
 BOOST_PYTHON_MODULE(deprecation_policy) {
   bp::def("some_deprecated_function", some_deprecated_function,
-          eigenpy::deprecation_warning_policy<DeprecationType::DEPRECATION>());
+          eigenpy::deprecated_function<DeprecationType::DEPRECATION>());
   bp::def("some_future_deprecated_function", some_future_deprecated_function,
-          eigenpy::deprecation_warning_policy<DeprecationType::FUTURE>());
+          eigenpy::deprecated_function<DeprecationType::FUTURE>());
+
+  bp::class_<X>("X", bp::init<>(bp::args("self")))
+      .def("deprecated_member_function", &X::deprecated_member_function,
+           eigenpy::deprecated_member<>());
 }

unittest/python/test_deprecation_policy.py

-from deprecation_policy import some_deprecated_function, some_future_deprecated_function
+from deprecation_policy import (
+    X,
+    some_deprecated_function,
+    some_future_deprecated_function,
+)
 
 some_deprecated_function()
 some_future_deprecated_function()
+X().deprecated_member_function()