refactor: Migrate to C++20 (endless-sky#10264)

.github/workflows/cd.yaml

@@ -28,7 +28,7 @@ jobs:
       - name: Install dependencies
         run: |
           sudo apt-get update
-          sudo apt-get install -y --no-install-recommends libxmu-dev libxi-dev libgl-dev libglu1-mesa-dev libgles2-mesa-dev libwayland-dev libxkbcommon-dev libegl1-mesa-dev fuse
+          sudo apt-get install -y --no-install-recommends libxmu-dev libxi-dev libgl-dev libglu1-mesa-dev libgles2-mesa-dev libwayland-dev libxkbcommon-dev libegl1-mesa-dev libfuse2
       - name: Setup sccache
         uses: ./.github/sccache
       - name: Adjust version strings

.github/workflows/cd_release.yaml

@@ -22,7 +22,7 @@ jobs:
       - name: Install dependencies
         run: |
           sudo apt-get update
-          sudo apt-get install -y --no-install-recommends libxmu-dev libxi-dev libgl-dev libglu1-mesa-dev libgles2-mesa-dev libwayland-dev libxkbcommon-dev libegl1-mesa-dev fuse
+          sudo apt-get install -y --no-install-recommends libxmu-dev libxi-dev libgl-dev libglu1-mesa-dev libgles2-mesa-dev libwayland-dev libxkbcommon-dev libegl1-mesa-dev libfuse2
       - name: Setup sccache
         uses: ./.github/sccache
       - uses: lukka/get-cmake@latest

.github/workflows/ci.yml

@@ -56,7 +56,7 @@ jobs:
     - name: Install development dependencies
       run: |
         sudo apt-get update
-        sudo apt-get install -y --no-install-recommends libxmu-dev libxi-dev libgl-dev libglu1-mesa-dev libgles2-mesa-dev libwayland-dev libxkbcommon-dev libegl1-mesa-dev libosmesa6 mesa-utils libglvnd-dev x11-utils
+        sudo apt-get install -y --no-install-recommends libxmu-dev libxi-dev libgl-dev libglu1-mesa-dev libgles2-mesa-dev libwayland-dev libxkbcommon-dev libegl1-mesa-dev libosmesa6 mesa-utils libglvnd-dev x11-utils catch2
     - name: Disable VM sound card
       run: |
         sudo sh -c 'echo "pcm.!default { type plug slave.pcm \"null\" }"  >> /etc/asound.conf'

CMakeLists.txt

@@ -14,8 +14,8 @@ cmake_dependent_option(ES_CREATE_BUNDLE "Create a Bundle instead of an executabl
 # Support Debug and Release configurations.
 set(CMAKE_CONFIGURATION_TYPES "Debug" "Release" CACHE STRING "" FORCE)
 
-# Use C++17 without any compiler specific extensions.
-set(CMAKE_CXX_STANDARD 17 CACHE STRING "")
+# Use C++20 without any compiler specific extensions.
+set(CMAKE_CXX_STANDARD 20 CACHE STRING "")
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 set(CMAKE_CXX_EXTENSIONS OFF)
 # Use LTO for Release builds only.

SConstruct

@@ -60,7 +60,7 @@ Help(opts.GenerateHelpText(env))
 #   $ CXXFLAGS=-msse3 scons
 #   $ CXXFLAGS=-march=native scons
 # or modify the `flags` variable:
-flags = ["-std=c++17", "-Wall", "-pedantic-errors", "-Wold-style-cast", "-fno-rtti"]
+flags = ["-std=c++20", "-Wall", "-pedantic-errors", "-Wold-style-cast", "-fno-rtti"]
 if env["mode"] != "debug":
 	flags += ["-Werror", "-O3", "-flto"]
 	env.Append(LINKFLAGS = ["-O3", "-flto"])

source/Depreciation.cpp

@@ -101,7 +101,7 @@ void Depreciation::Save(DataWriter &out, int day) const
 		WriteSorted(ships,
 			[](const ShipElement *lhs, const ShipElement *rhs)
 				{ return lhs->first->TrueModelName() < rhs->first->TrueModelName(); },
-			[=, &out](const ShipElement &sit)
+			[=, this, &out](const ShipElement &sit)
 			{
 				out.Write("ship", sit.first->TrueModelName());
 				out.BeginChild();
@@ -120,7 +120,7 @@ void Depreciation::Save(DataWriter &out, int day) const
 		WriteSorted(outfits,
 			[](const OutfitElement *lhs, const OutfitElement *rhs)
 				{ return lhs->first->TrueName() < rhs->first->TrueName(); },
-			[=, &out](const OutfitElement &oit)
+			[=, this, &out](const OutfitElement &oit)
 			{
 				out.Write("outfit", oit.first->TrueName());
 				out.BeginChild();

tests/CMakeLists.txt

@@ -8,10 +8,11 @@ if(NOT MSVC)
 		"-Wall" "-pedantic-errors" "-Wold-style-cast" "-fno-rtti")
 endif()
 
+find_package(Catch2 CONFIG REQUIRED)
+
 # Every source file (and header file) should be listed here.
 # If you add a new file, add it to this list.
 target_sources(EndlessSkyTests PRIVATE
-	unit/include/catch.hpp
 	unit/include/datanode-factory.h
 	unit/include/es-test.hpp
 	unit/include/output-capture.hpp
@@ -73,6 +74,7 @@ list(APPEND INTEGRATION_TESTS
 )
 
 target_include_directories(EndlessSkyTests PRIVATE unit/include)
+target_link_libraries(EndlessSkyTests PRIVATE Catch2::Catch2WithMain)
 target_link_libraries(EndlessSkyTests PRIVATE ExternalLibraries $<TARGET_OBJECTS:EndlessSkyLib>)
 
 # CTest support for our unit tests.