From f10d428cfab58548264ea54e6d6f26c65af36ef4 Mon Sep 17 00:00:00 2001
From: sha512sum <linuxnyasha@tutanota.com>
Date: Tue, 2 Jul 2024 16:50:12 +0000
Subject: [PATCH] Add constexpr check example

---
 CMakeLists.txt                   | 14 ++++++-----
 examples/src/constexpr_check.cpp | 40 ++++++++++++++++++++++++++++++++
 2 files changed, 48 insertions(+), 6 deletions(-)
 create mode 100644 examples/src/constexpr_check.cpp

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 25eb3b6..e35c8c3 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -68,11 +68,13 @@ if(ENABLE_EXAMPLES)
   file(GLOB EXAMPLES_SRC "examples/src/*.cpp")
   foreach(EXAMPLE_SRC ${EXAMPLES_SRC})
       get_filename_component(EXAMPLE_NAME ${EXAMPLE_SRC} NAME_WE)
-      add_executable(${EXAMPLE_NAME} ${EXAMPLE_SRC})
-      target_link_libraries(${EXAMPLE_NAME} cserver)
-      set_property(TARGET ${EXAMPLE_NAME} PROPERTY CXX_STANDARD 23)
-      set_target_properties(${EXAMPLE_NAME} PROPERTIES
-          RUNTIME_OUTPUT_DIRECTORY "${CMAKE_SOURCE_DIR}/examples/output/")
-endforeach()
+      if(NOT ${EXAMPLE_NAME} STREQUAL "constexpr_check")
+          add_executable(${EXAMPLE_NAME} ${EXAMPLE_SRC})
+          target_link_libraries(${EXAMPLE_NAME} cserver)
+          set_property(TARGET ${EXAMPLE_NAME} PROPERTY CXX_STANDARD 23)
+          set_target_properties(${EXAMPLE_NAME} PROPERTIES
+              RUNTIME_OUTPUT_DIRECTORY "${CMAKE_SOURCE_DIR}/examples/output/")
+      endif()
+  endforeach()
 endif()
 
diff --git a/examples/src/constexpr_check.cpp b/examples/src/constexpr_check.cpp
new file mode 100644
index 0000000..dec73c2
--- /dev/null
+++ b/examples/src/constexpr_check.cpp
@@ -0,0 +1,40 @@
+#include <cserver/components/loggable_component_base.hpp>
+
+
+struct SomeComponent {
+  static constexpr utempl::ConstexprString kName = "component";
+
+  constexpr SomeComponent(auto&) {};
+};
+
+
+struct SomeComponent2 {
+  static constexpr utempl::ConstexprString kName = "component2";
+
+  constexpr SomeComponent2(auto&) {};
+};
+
+struct OtherComponent {
+  static constexpr utempl::ConstexprString kName = "other";
+
+  auto Foo(auto& context) -> void {
+    context.template FindComponent<"component2">(); // UB on runtime with old check
+                                                    // Compile time error with new check(check via loopholes)
+  };
+
+  constexpr OtherComponent(auto& context) {
+    context.template FindComponent<"component">();
+    Foo(context);
+  };
+};
+
+
+auto main() -> int {
+  cserver::ServiceContextBuilder{}
+    .AppendConfigParam<"threads", 8>()
+    .Append<SomeComponent>()
+    .Append<SomeComponent2>()
+    .Append<OtherComponent>()
+    .Sort()
+  .Run();
+};