build: replace WERROR with CMAKE_COMPILE_WARNING_AS_ERROR

-Werror is added to the previous releases job, given it runs on Ubuntu
22.04, which uses an older CMake.

`--compile-no-warning-as-error` can be used, if needed, in future, to
suppress the `CMAKE_COMPILE_WARNING_AS_ERROR` behaviour from a CI
config.

CMAKE_COMPILE_WARNING_AS_ERROR was added to CMake in 3.24.
See https://cmake.org/cmake/help/latest/prop_tgt/COMPILE_WARNING_AS_ERROR.html.

Co-authored-by: willcl-ark <will8clark@gmail.com>

.github/ci-test-each-commit-exec.py

@@ -38,7 +38,7 @@ def main():
         "-DAPPEND_CXXFLAGS='-O3 -g2'",
         "-DAPPEND_CFLAGS='-O3 -g2'",
         "-DCMAKE_BUILD_TYPE=Debug",
-        "-DWERROR=ON",
+        "-DCMAKE_COMPILE_WARNING_AS_ERROR=ON",
         "--preset=dev-mode",
         # Tolerate unused member functions in intermediate commits in a pull request
         "-DCMAKE_CXX_FLAGS=-Wno-error=unused-member-function",

.github/workflows/ci.yml

@@ -218,10 +218,10 @@ jobs:
         job-type: [standard, fuzz]
         include:
           - job-type: standard
-            generate-options: '-DBUILD_BENCH=ON -DBUILD_KERNEL_LIB=ON -DBUILD_UTIL_CHAINSTATE=ON -DWERROR=ON'
+            generate-options: '-DBUILD_BENCH=ON -DBUILD_KERNEL_LIB=ON -DBUILD_UTIL_CHAINSTATE=ON -DCMAKE_COMPILE_WARNING_AS_ERROR=ON'
             job-name: 'Windows native, VS 2022'
           - job-type: fuzz
-            generate-options: '-DVCPKG_MANIFEST_NO_DEFAULT_FEATURES=ON -DVCPKG_MANIFEST_FEATURES="wallet" -DBUILD_GUI=OFF -DWITH_ZMQ=OFF -DBUILD_FOR_FUZZING=ON -DWERROR=ON'
+            generate-options: '-DVCPKG_MANIFEST_NO_DEFAULT_FEATURES=ON -DVCPKG_MANIFEST_FEATURES="wallet" -DBUILD_GUI=OFF -DWITH_ZMQ=OFF -DBUILD_FOR_FUZZING=ON -DCMAKE_COMPILE_WARNING_AS_ERROR=ON'
             job-name: 'Windows native, fuzz, VS 2022'
 
     steps:

CMakeLists.txt

@@ -119,7 +119,6 @@ endif()
 cmake_dependent_option(BUILD_WALLET_TOOL "Build bitcoin-wallet tool." ${BUILD_TESTS} "ENABLE_WALLET" OFF)
 
 option(REDUCE_EXPORTS "Attempt to reduce exported symbols in the resulting executables." OFF)
-option(WERROR "Treat compiler warnings as errors." OFF)
 option(WITH_CCACHE "Attempt to use ccache for compiling." ON)
 
 option(WITH_ZMQ "Enable ZMQ notifications." OFF)
@@ -568,19 +567,6 @@ if(REDUCE_EXPORTS)
   try_append_linker_flag("-Wl,-no_exported_symbols" VAR CMAKE_EXE_LINKER_FLAGS)
 endif()
 
-if(WERROR)
-  if(MSVC)
-    set(werror_flag "/WX")
-  else()
-    set(werror_flag "-Werror")
-  endif()
-  try_append_cxx_flags(${werror_flag} TARGET core_interface SKIP_LINK RESULT_VAR compiler_supports_werror)
-  if(NOT compiler_supports_werror)
-    message(FATAL_ERROR "WERROR set but ${werror_flag} is not usable.")
-  endif()
-  unset(werror_flag)
-endif()
-
 # Prefer Unix-style package components over frameworks on macOS.
 # This improves compatibility with Python version managers.
 set(Python3_FIND_FRAMEWORK LAST CACHE STRING "")
@@ -685,7 +671,7 @@ message("Cross compiling ....................... ${cross_status}")
 message("C++ compiler .......................... ${CMAKE_CXX_COMPILER_ID} ${CMAKE_CXX_COMPILER_VERSION}, ${CMAKE_CXX_COMPILER}")
 include(FlagsSummary)
 flags_summary()
-message("Treat compiler warnings as errors ..... ${WERROR}")
+message("Treat compiler warnings as errors ..... ${CMAKE_COMPILE_WARNING_AS_ERROR}")
 message("Use ccache for compiling .............. ${WITH_CCACHE}")
 message("\n")
 if(configure_warnings)

ci/test/00_setup_env_native_previous_releases.sh

@@ -15,13 +15,14 @@ export TEST_RUNNER_EXTRA="--previous-releases --coverage --extended --exclude fe
 export GOAL="install"
 export CI_LIMIT_STACK_SIZE=1
 export DOWNLOAD_PREVIOUS_RELEASES="true"
+# Use -Werror as the CMake version does not support CMAKE_COMPILE_WARNING_AS_ERROR
 export BITCOIN_CONFIG="\
  --preset=dev-mode \
  -DREDUCE_EXPORTS=ON \
  -DCMAKE_BUILD_TYPE=Debug \
- -DCMAKE_C_FLAGS='-funsigned-char' \
+ -DCMAKE_C_FLAGS='-funsigned-char -Werror' \
  -DCMAKE_C_FLAGS_DEBUG='-g2 -O2' \
- -DCMAKE_CXX_FLAGS='-funsigned-char' \
+ -DCMAKE_CXX_FLAGS='-funsigned-char -Werror' \
  -DCMAKE_CXX_FLAGS_DEBUG='-g2 -O2' \
  -DAPPEND_CPPFLAGS='-DBOOST_MULTI_INDEX_ENABLE_SAFE_MODE' \
 "

ci/test/03_test_script.sh

@@ -81,13 +81,10 @@ if [ "$DOWNLOAD_PREVIOUS_RELEASES" = "true" ]; then
   test/get_previous_releases.py --target-dir "$PREVIOUS_RELEASES_DIR"
 fi
 
-BITCOIN_CONFIG_ALL="-DBUILD_BENCH=ON -DBUILD_FUZZ_BINARY=ON"
+BITCOIN_CONFIG_ALL="-DCMAKE_COMPILE_WARNING_AS_ERROR=ON -DBUILD_BENCH=ON -DBUILD_FUZZ_BINARY=ON"
 if [ -z "$NO_DEPENDS" ]; then
   BITCOIN_CONFIG_ALL="${BITCOIN_CONFIG_ALL} -DCMAKE_TOOLCHAIN_FILE=$DEPENDS_DIR/$HOST/toolchain.cmake"
 fi
-if [ -z "$NO_WERROR" ]; then
-  BITCOIN_CONFIG_ALL="${BITCOIN_CONFIG_ALL} -DWERROR=ON"
-fi
 
 ccache --zero-stats