From b8d377f7f032e2bb27cc51d77bc9c627fc37edea Mon Sep 17 00:00:00 2001
From: Christopher Bazley <119876938+chrisbazley@users.noreply.github.com>
Date: Mon, 28 Sep 2026 15:20:56 +0100
Subject: [PATCH] Make CI diagnostics fatal

---
 .github/workflows/cmake-multi-platform.yml |  2 ++
 CMakeLists.txt                             | 13 +++++++++++--
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/cmake-multi-platform.yml b/.github/workflows/cmake-multi-platform.yml
index 91dd64f..f600594 100644
--- a/.github/workflows/cmake-multi-platform.yml
+++ b/.github/workflows/cmake-multi-platform.yml
@@ -58,6 +58,7 @@ jobs:
         cmake -B ${{ steps.strings.outputs.build-output-dir }}
         -DCMAKE_C_COMPILER=${{ matrix.c_compiler }}
         -DCMAKE_BUILD_TYPE=${{ matrix.build_type }}
+        -DWARNINGS_AS_ERRORS=ON
         -DUSE_OPTIONAL=OFF
         -DUSE_FORTIFY=${{ matrix.build_type == 'Debug' && matrix.c_compiler != 'clang' }}
         -S ${{ github.workspace }}
@@ -151,6 +152,7 @@ jobs:
             -DCMAKE_BUILD_TYPE=${{ matrix.build_type }} \
             -DCMAKE_C_COMPILER="$OPTIONAL_CLANG_ROOT/bin/clang" \
             -DCLANG_TIDY_EXE="$OPTIONAL_CLANG_ROOT/bin/clang-tidy" \
+            -DWARNINGS_AS_ERRORS=ON \
             -DUSE_OPTIONAL=ON \
             -DUSE_FORTIFY=${{ matrix.use_fortify }} \
             -DENABLE_CLANG_TIDY=ON
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 0a877fd..2f686ac 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -5,6 +5,7 @@ include(FetchContent)
 option(USE_OPTIONAL "Enable the _Optional qualifier" OFF)
 option(USE_FORTIFY "Enable Fortify memory-allocation checking" OFF)
 option(ENABLE_CLANG_TIDY "Run clang-tidy during compilation" OFF)
+option(WARNINGS_AS_ERRORS "Treat compiler warnings as errors" OFF)
 
 FetchContent_Declare(CBUtil GIT_REPOSITORY https://github.com/chrisbazley/CBUtilLib.git GIT_TAG main)
 
@@ -46,7 +47,15 @@ else()
     add_compile_options(-Wall -Wextra -Wsign-compare -pedantic)
 endif()
 
-if(ENABLE_CLANG_TIDY)
+if(WARNINGS_AS_ERRORS AND CMAKE_SOURCE_DIR STREQUAL PROJECT_SOURCE_DIR)
+    if(MSVC)
+        add_compile_options(/WX)
+    else()
+        add_compile_options(-Werror)
+    endif()
+endif()
+
+if(ENABLE_CLANG_TIDY AND CMAKE_SOURCE_DIR STREQUAL PROJECT_SOURCE_DIR)
     if(NOT CMAKE_C_COMPILER_ID MATCHES "Clang|AppleClang")
         message(FATAL_ERROR "ENABLE_CLANG_TIDY requires Clang")
     endif()
@@ -64,7 +73,7 @@ if(ENABLE_CLANG_TIDY)
     set(CMAKE_C_CLANG_TIDY
         "${CLANG_TIDY_EXE}"
         "--checks=-*,clang-analyzer-*,-clang-analyzer-security.insecureAPI.*"
-        "--warnings-as-errors=clang-analyzer-optionality.*"
+        "--warnings-as-errors=clang-analyzer-*"
     )
 
     message(STATUS "clang-tidy: ${CLANG_TIDY_EXE}")