fix issue with option defaults not propagating to option groups (#450)

* Add already passing check

* Remove too modern clang-tidy-9 check

.clang-tidy

@@ -6,24 +6,24 @@ FormatStyle: file
 Checks: '
 -*,
 google-*,
--google-runtime-int,
 -google-runtime-references,
 llvm-include-order,
 llvm-namespace-comment,
 misc-throw-by-value-catch-by-reference,
 modernize*,
+-modernize-use-trailing-return-type,
 readability-container-size-empty,
 '
 
 WarningsAsErrors: '
 -*,
 google-*,
--google-runtime-int,
 -google-runtime-references,
 llvm-include-order,
 llvm-namespace-comment,
 misc-throw-by-value-catch-by-reference,
 modernize*,
+-modernize-use-trailing-return-type,
 readability-container-size-empty,
 '
 

azure-pipelines.yml

@@ -62,7 +62,8 @@ jobs:
         cli11.std: 11
       Windowslatest:
         vmImage: 'windows-2019'
-        cli11.std: 17
+        cli11.std: 20
+        cli11.options: -DCMAKE_CXX_FLAG="/std:c++latest"
   pool:
     vmImage: $(vmImage)
   steps:
@@ -113,6 +114,10 @@ jobs:
         containerImage: silkeh/clang:8
         cli11.std: 17
         cli11.options: -DCLI11_FORCE_LIBCXX=ON
+      clang10_20:
+        containerImage: helics/buildenv:clang10-builder
+        cli11.std: 20
+        cli11.options: -DCLI11_FORCE_LIBCXX=ON -DCMAKE_CXX_FLAGS=-std=c++20
   container: $[ variables['containerImage'] ]
   steps:
     - template: .ci/azure-cmake.yml

include/CLI/App.hpp

@@ -993,7 +993,7 @@ class App {
     /// creates an option group as part of the given app
     template <typename T = Option_group>
     T *add_option_group(std::string group_name, std::string group_description = "") {
-        auto option_group = std::make_shared<T>(std::move(group_description), group_name, nullptr);
+        auto option_group = std::make_shared<T>(std::move(group_description), group_name, this);
         auto ptr = option_group.get();
         // move to App_p for overload resolution on older gcc versions
         App_p app_ptr = std::dynamic_pointer_cast<App>(option_group);
@@ -3086,7 +3086,18 @@ inline std::string help(const App *app, const Error &e) {
 namespace detail {
 /// This class is simply to allow tests access to App's protected functions
 struct AppFriend {
+#ifdef CLI11_CPP14
 
+    /// Wrap _parse_short, perfectly forward arguments and return
+    template <typename... Args> static decltype(auto) parse_arg(App *app, Args &&... args) {
+        return app->_parse_arg(std::forward<Args>(args)...);
+    }
+
+    /// Wrap _parse_subcommand, perfectly forward arguments and return
+    template <typename... Args> static decltype(auto) parse_subcommand(App *app, Args &&... args) {
+        return app->_parse_subcommand(std::forward<Args>(args)...);
+    }
+#else
     /// Wrap _parse_short, perfectly forward arguments and return
     template <typename... Args>
     static auto parse_arg(App *app, Args &&... args) ->
@@ -3100,6 +3111,7 @@ struct AppFriend {
         typename std::result_of<decltype (&App::_parse_subcommand)(App, Args...)>::type {
         return app->_parse_subcommand(std::forward<Args>(args)...);
     }
+#endif
     /// Wrap the fallthrough parent function to make sure that is working correctly
     static App *get_fallthrough_parent(App *app) { return app->_get_fallthrough_parent(); }
 };

tests/OptionGroupTest.cpp

@@ -374,6 +374,18 @@ TEST_F(TApp, InvalidOptions) {
     EXPECT_THROW(ogroup->add_option(opt), CLI::OptionNotFound);
 }
 
+TEST_F(TApp, OptionGroupInheritedOptionDefaults) {
+    app.option_defaults()->ignore_case();
+    auto ogroup = app.add_option_group("clusters");
+    int res{0};
+    ogroup->add_option("--test1", res);
+
+    args = {"--Test1", "5"};
+    run();
+    EXPECT_EQ(res, 5);
+    EXPECT_EQ(app.count_all(), 1u);
+}
+
 struct ManyGroups : public TApp {
 
     CLI::Option_group *main{nullptr};