From c6c34b02d15054ec76e965617cd8798aff3d1dad Mon Sep 17 00:00:00 2001
From: ClausKlein <claus.klein@arcormail.de>
Date: Tue, 29 Mar 2022 10:38:34 +0200
Subject: [PATCH] add and use WarningsAsErrors cmake module

export cxx_std_20 with target_compile_features()
but do not export pedantic Waning options!
---
 CMakeLists.txt               |  9 ++++++---
 cmake/WarningsAsErrors.cmake | 12 ++++++++++++
 test/CMakeLists.txt          | 11 ++---------
 3 files changed, 20 insertions(+), 12 deletions(-)
 create mode 100644 cmake/WarningsAsErrors.cmake

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 71b2af0..70b0670 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -45,13 +45,16 @@ file(GLOB_RECURSE sources CONFIGURE_DEPENDS "${CMAKE_CURRENT_SOURCE_DIR}/source/
 # Note: for header-only libraries change all PUBLIC flags to INTERFACE and create an interface
 # target: add_library(${PROJECT_NAME} INTERFACE)
 add_library(${PROJECT_NAME} ${headers} ${sources})
-set_target_properties(${PROJECT_NAME} PROPERTIES CXX_STANDARD 17)
+target_compile_features(${PROJECT_NAME} PUBLIC cxx_std_20)
+
+# enable compiler warnings
+include(cmake/WarningsAsErrors.cmake)
 
 # being a cross-platform target, we enforce standards conformance on MSVC
-target_compile_options(${PROJECT_NAME} PUBLIC "$<$<COMPILE_LANG_AND_ID:CXX,MSVC>:/permissive->")
+target_compile_options(${PROJECT_NAME} PRIVATE "$<$<COMPILE_LANG_AND_ID:CXX,MSVC>:/permissive->")
 
 # Link dependencies
-target_link_libraries(${PROJECT_NAME} PRIVATE fmt::fmt)
+target_link_libraries(${PROJECT_NAME} PUBLIC fmt::fmt)
 
 target_include_directories(
   ${PROJECT_NAME} PUBLIC $<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/include>
diff --git a/cmake/WarningsAsErrors.cmake b/cmake/WarningsAsErrors.cmake
new file mode 100644
index 0000000..b23660c
--- /dev/null
+++ b/cmake/WarningsAsErrors.cmake
@@ -0,0 +1,12 @@
+if(CMAKE_CXX_COMPILER_ID MATCHES "Clang" AND CMAKE_CXX_SIMULATE_ID MATCHES "MSVC")
+  target_compile_options(${PROJECT_NAME} PRIVATE /W4 /WX)
+elseif(CMAKE_CXX_COMPILER_ID MATCHES "GNU|Clang")
+  target_compile_options(${PROJECT_NAME} PRIVATE -Wall -Wextra -Wpedantic -Werror -Wshadow)
+
+  if(CMAKE_CXX_COMPILER_ID STREQUAL "Clang" AND CMAKE_CXX_COMPILER_VERSION GREATER_EQUAL 10.0)
+    target_compile_options(${PROJECT_NAME} PRIVATE -Wdeprecated-copy-dtor -Wnewline-eof)
+  endif()
+elseif(CMAKE_CXX_COMPILER_ID STREQUAL "MSVC")
+  string(REGEX REPLACE " /W[0-4]" "" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
+  target_compile_options(${PROJECT_NAME} PRIVATE /W4 /WX)
+endif()
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 3dd0879..ae27db6 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -33,17 +33,10 @@ endif()
 file(GLOB sources CONFIGURE_DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/source/*.cpp)
 add_executable(${PROJECT_NAME} ${sources})
 target_link_libraries(${PROJECT_NAME} doctest::doctest Greeter::Greeter)
-set_target_properties(${PROJECT_NAME} PROPERTIES CXX_STANDARD 17)
+target_compile_features(${PROJECT_NAME} PRIVATE cxx_std_20)
 
 # enable compiler warnings
-if(NOT TEST_INSTALLED_VERSION)
-  if(CMAKE_CXX_COMPILER_ID MATCHES "Clang" OR CMAKE_CXX_COMPILER_ID MATCHES "GNU")
-    target_compile_options(Greeter PUBLIC -Wall -Wpedantic -Wextra -Werror)
-  elseif(MSVC)
-    target_compile_options(Greeter PUBLIC /W4 /WX)
-    target_compile_definitions(${PROJECT_NAME} PUBLIC DOCTEST_CONFIG_USE_STD_HEADERS)
-  endif()
-endif()
+include(../cmake/WarningsAsErrors.cmake)
 
 # ---- Add GreeterTests ----