maint: Enable -Werror compiler flag for GCC, Clang and AppleClang

CMakeLists.txt

@@ -19,7 +19,11 @@ 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)
-option(MAMBA_WARNING_AS_ERROR "Treat compiler warnings as errors" 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"

libmamba/CMakeLists.txt

@@ -264,6 +264,22 @@ set(
     ${LIBMAMBA_SOURCE_DIR}/api/shell.cpp
     ${LIBMAMBA_SOURCE_DIR}/api/update.cpp
 )
+# TODO: remove when switch to C++20
+if(CMAKE_CXX_COMPILER_ID STREQUAL "Clang" OR CMAKE_CXX_COMPILER_ID STREQUAL "AppleClang")
+    # This file uses capturing structured bindings, which was fixed in C++20
+    set_source_files_properties(
+        ${LIBMAMBA_SOURCE_DIR}/download/mirror_impl.cpp
+        PROPERTIES COMPILE_FLAGS -Wno-c++20-extensions
+    )
+endif()
+
+if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
+    # GCC reports dangling reference when using std::invoke with data members
+    set_source_files_properties(
+        ${LIBMAMBA_SOURCE_DIR}/solver/problems_graph.cpp
+        PROPERTIES COMPILE_FLAGS -Wno-error=dangling-reference
+    )
+endif()
 
 foreach(script ${SHELL_SCRIPTS})
     list(APPEND LIBMAMBA_SOURCES shell_scripts/${script}.cpp)

libmamba/ext/solv-cpp/src/pool.cpp

@@ -93,10 +93,17 @@ namespace solv
 
     namespace
     {
+// This function is only used in `assert()` expressions
+// That's why it might get reported as unused in Release builds
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wunused-function"
+
         auto is_reldep(::Id id) -> bool
         {
             return ISRELDEP(static_cast<std::make_unsigned_t<::Id>>(id)) != 0;
         }
+
+#pragma GCC diagnostic pop
     }
 
     auto ObjPoolView::get_string(StringId id) const -> std::string_view

libmamba/include/mamba/util/conditional.hpp

@@ -31,9 +31,7 @@ namespace mamba::util
         }
         else
         {
-            using int_t = Int;
-            return static_cast<int_t>(condition) * true_val
-                   + (int_t(1) - static_cast<int_t>(condition)) * false_val;
+            return condition ? true_val : false_val;
         }
     }
 }

libmamba/src/core/activation.cpp

@@ -554,11 +554,11 @@ namespace mamba
         auto conda_environment_env_vars = get_environment_vars(prefix);
 
         // TODO check with conda if that's really what's supposed to happen ...
-        std::remove_if(
+        void(std::remove_if(
             conda_environment_env_vars.begin(),
             conda_environment_env_vars.end(),
             [](auto& el) { return el.second == CONDA_ENV_VARS_UNSET_VAR; }
-        );
+        ));
 
         std::vector<std::string> clobbering_env_vars;
         for (auto& env_var : conda_environment_env_vars)

libmamba/src/core/thread_utils.cpp

@@ -29,6 +29,25 @@ namespace mamba
 #ifndef _WIN32
     namespace
     {
+// `sigaddset` might be implemented as a macro calling `__sigbits(int)` function
+// At the same time `sigset_t` might be `unsigned int`
+// This causes compiler warning
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wsign-conversion"
+
+        sigset_t get_sigset()
+        {
+            // block signals in this thread and subsequently
+            // spawned threads
+            sigset_t sigset;
+            sigemptyset(&sigset);
+            sigaddset(&sigset, SIGINT);
+            // sigaddset(&sigset, SIGTERM);
+            return sigset;
+        }
+
+#pragma GCC diagnostic pop
+
         std::thread::native_handle_type sig_recv_thread;
         std::atomic<bool> receiver_exists(false);
     }
@@ -74,12 +93,7 @@ namespace mamba
     {
         stop_receiver_thread();
 
-        // block signals in this thread and subsequently
-        // spawned threads
-        sigset_t sigset;
-        sigemptyset(&sigset);
-        sigaddset(&sigset, SIGINT);
-        // sigaddset(&sigset, SIGTERM);
+        sigset_t sigset = get_sigset();
         pthread_sigmask(SIG_BLOCK, &sigset, nullptr);
         std::thread receiver(handler, sigset);
         sig_recv_thread = receiver.native_handle();

libmamba/src/solver/libsolv/matcher.cpp

@@ -193,7 +193,7 @@ namespace mamba::solver::libsolv
             return { std::cref(it->second) };
         }
 
-        return specs::Channel::resolve(std::move(uc), channel_params())
+        return specs::Channel::resolve(uc, channel_params())
             .transform(
                 [&](channel_list&& chan)
                 {

libmambapy/CMakeLists.txt

@@ -32,6 +32,14 @@ pybind11_add_module(
     src/libmambapy/bindings/solver.cpp
     src/libmambapy/bindings/solver_libsolv.cpp
 )
+# TODO: remove when `SubdirData::cache_path()` is removed
+if(CMAKE_CXX_COMPILER_ID STREQUAL "Clang" OR CMAKE_CXX_COMPILER_ID STREQUAL "AppleClang")
+    # This file uses capturing structured bindings, which was fixed in C++20
+    set_source_files_properties(
+        src/libmambapy/bindings/legacy.cpp
+        PROPERTIES COMPILE_FLAGS -Wno-error=deprecated-declarations
+    )
+endif()
 
 target_include_directories(bindings PRIVATE src/libmambapy/bindings)