From a4881dda8b4c3d9e92ebd5a895d72838f28f509c Mon Sep 17 00:00:00 2001
From: Lars Melchior <TheLartians@users.noreply.github.com>
Date: Wed, 15 Apr 2020 09:12:12 +0200
Subject: [PATCH] enforce standards conformance on MSVC and fix warning flags
 (#10)

* enforce standards conformance on MSVC

* add \W4 flag for test compilation

* enable compiler warnings for the library target when building tests

* update note on testing frameworks

* turns out only clang understands strongly typed enums
---
 CMakeLists.txt      |  9 ++++++---
 source/greeter.cpp  |  3 ---
 test/CMakeLists.txt | 23 ++++++++++++++---------
 3 files changed, 20 insertions(+), 15 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index f2332cd..2913c6b 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -10,7 +10,7 @@ project(Greeter
 
 # ---- Include guards ----
 
-if(${PROJECT_SOURCE_DIR} STREQUAL ${PROJECT_BINARY_DIR})
+if(PROJECT_SOURCE_DIR STREQUAL PROJECT_BINARY_DIR)
     message(FATAL_ERROR "In-source builds not allowed. Please make a new directory (called a build directory) and run CMake from there.")
 endif()
 
@@ -35,17 +35,20 @@ CPMAddPackage(
 
 # ---- Create library ----
 
-# Note: for single header libraries create an interface target instead:
+# Note: for header-only libraries change all PUBLIC flags to INTERFACE and create an interface target:
 # add_library(Greeter INTERFACE)  
 # set_target_properties(Greeter PROPERTIES INTERFACE_COMPILE_FEATURES cxx_std_17)
 
 add_library(Greeter ${headers} ${sources})
+
 set_target_properties(Greeter PROPERTIES CXX_STANDARD 17)
 
+# beeing a cross-platform target, we enforce enforce standards conformance on MSVC
+target_compile_options(Greeter PUBLIC "$<$<BOOL:${MSVC}>:/permissive->")
+
 # Link dependencies (if required)
 # target_link_libraries(Greeter PUBLIC cxxopts)
 
-# Note: change PUBLIC to INTERFACE for single header libraries  
 target_include_directories(Greeter
   PUBLIC
     $<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/include>
diff --git a/source/greeter.cpp b/source/greeter.cpp
index 6295269..e75363f 100644
--- a/source/greeter.cpp
+++ b/source/greeter.cpp
@@ -6,10 +6,7 @@ Greeter::Greeter(std::string _name) : name(_name) {}
 
 std::string Greeter::greet(LanguageCode lang) const {
   switch (lang) {
-#if defined(_WIN32) || defined(WIN32)
-    // this silences a MSVC warning as it does not seem to understand strongly-typed enums
     default:
-#endif
     case LanguageCode::EN:
       return "Hello, " + name + "!";
     case LanguageCode::DE:
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 9b4ce42..74109f6 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -40,26 +40,31 @@ file(GLOB sources CONFIGURE_DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/source/*.cpp)
 add_executable(GreeterTests ${sources})
 target_link_libraries(GreeterTests doctest Greeter)
 
-if (CMAKE_CXX_COMPILER_ID MATCHES "Clang" OR CMAKE_CXX_COMPILER_ID MATCHES "GNU")
-  set_target_properties(GreeterTests PROPERTIES CXX_STANDARD 17 COMPILE_FLAGS "-Wall -pedantic -Wextra -Werror")
-else()
-  set_target_properties(GreeterTests PROPERTIES CXX_STANDARD 17)
+set_target_properties(GreeterTests PROPERTIES CXX_STANDARD 17)
+
+# 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 -pedantic -Wextra -Werror)
+  elseif(MSVC)
+    target_compile_options(Greeter PUBLIC /W4)
+  endif()
 endif()
 
 # ---- Add GreeterTests ----
 
 ENABLE_TESTING() 
 
-# use doctest_discover_tests for better CTest support
+# Note: doctest and similar testing frameworks can automatically configure CMake tests
+# For other testing frameworks add the tests target instead:
+# ADD_TEST(GreeterTests GreeterTests)
+
 include(${doctest_SOURCE_DIR}/scripts/cmake/doctest.cmake)
 doctest_discover_tests(GreeterTests)
 
-# Note: for general testing frameworks use:
-# ADD_TEST(GreeterTests GreeterTests)
-
 # ---- code coverage ----
 
 if (ENABLE_TEST_COVERAGE)
-  set_target_properties(Greeter PROPERTIES CXX_STANDARD 17 COMPILE_FLAGS "-O0 -g -fprofile-arcs -ftest-coverage --coverage")
+  target_compile_options(Greeter PRIVATE -O0 -g -fprofile-arcs -ftest-coverage --coverage)
   target_link_options(Greeter PUBLIC "--coverage")
 endif()