warning as error default to OFF and enabled in CI (#3814)

.github/workflows/unix_impl.yml

@@ -40,6 +40,7 @@ jobs:
             --preset mamba-unix-shared-${{ inputs.build_type }}  \
             -D CMAKE_CXX_COMPILER_LAUNCHER=sccache \
             -D CMAKE_C_COMPILER_LAUNCHER=sccache \
+            -D MAMBA_WARNING_AS_ERROR=ON \
             -D BUILD_LIBMAMBAPY=OFF \
             -D ENABLE_MAMBA_ROOT_PREFIX_FALLBACK=OFF
           cmake --build build/ --parallel

CMakeLists.txt

@@ -19,11 +19,8 @@ option(BUILD_LIBMAMBA_TESTS "Build libmamba C++ tests" OFF)
 option(BUILD_MAMBA "Build mamba" OFF)
 option(BUILD_MICROMAMBA "Build micromamba" OFF)
 option(BUILD_MAMBA_PACKAGE "Build mamba package utility" OFF)
-if(MSVC)
 option(MAMBA_WARNING_AS_ERROR "Treat compiler warnings as errors" OFF)
-else()
-    option(MAMBA_WARNING_AS_ERROR "Treat compiler warnings as errors" ON)
-endif()
+
 set(
     MAMBA_LTO
     "Default"

libmambapy/setup.py

@@ -1,6 +1,7 @@
 import importlib.util
 import os
 import pathlib
+import sys
 
 import skbuild
 import skbuild.constants
@@ -23,6 +24,13 @@ def libmambapy_version():
     return ver.__version__
 
 
+def get_cmake_args():
+    cmake_args = [f"-DMAMBA_INSTALL_PYTHON_EXT_LIBDIR={CMAKE_INSTALL_DIR()}/src/libmambapy"]
+    if sys.platform != "win32" and sys.platform != "cygwin":
+        cmake_args += ["-DMAMBA_WARNING_AS_ERROR=ON"]
+    return cmake_args
+
+
 skbuild.setup(
     version=libmambapy_version(),
     packages=["libmambapy", "libmambapy.bindings", "libmambapy.solver"],
@@ -31,7 +39,5 @@ skbuild.setup(
     cmake_languages=["CXX"],
     cmake_minimum_required_version="3.17",
     cmake_install_dir="src/libmambapy",  # Must match package_dir layout
-    cmake_args=[
-        f"-DMAMBA_INSTALL_PYTHON_EXT_LIBDIR={CMAKE_INSTALL_DIR()}/src/libmambapy",
-    ],
+    cmake_args=get_cmake_args(),
 )