Handling a version mismatch of the compiler version between conan and CMake

Question

I am developing on macOS with Apple-clang v12 being the default compiler via the Xcode installation. Since valgrind still does not support Big Sur and the Apple version does not support Google Sanitizers I have to manually install llvm v11.1 via homebrew to leverage Google Sanitizers to have any memory leak detection tool enabled.

Unfortunately this causes some issues with conan and its integration with CMake and CLion, my IDE. Since my dependencies do not provide binaries for my architecture using clang instead of Apple-clang they have to built locally. Unfortunately conan and CMake error when invoking them with two contradictory error messages:

conan install /Users/near/Code/personal/blight -if=/Users/near/Code/personal/blight/cmake-build-debug -pr=LLVM11Debug --build=missing
Configuration:
[settings]
arch=x86_64
arch_build=x86_64
build_type=Debug
compiler=clang
compiler.libcxx=libstdc++
compiler.version=11
os=Macos
os_build=Macos
[options]
[build_requires]
[env]

fmt/7.1.3: WARN: Package binary is corrupted, removing: 2284170e72f485ebb586c7bd784f294475c25e5e
conanfile.txt: Installing package
Requirements
    fmt/7.1.3 from 'conan-center' - Cache
    spdlog/1.8.5 from 'conan-center' - Cache
Packages
    fmt/7.1.3:2284170e72f485ebb586c7bd784f294475c25e5e - Build
    spdlog/1.8.5:b744aef5cdad24eec65bb267843e16ad74c9ad39 - Build

Installing (downloading, building) binaries...
fmt/7.1.3: WARN: Build folder is dirty, removing it: /Users/near/.conan/data/fmt/7.1.3/_/_/build/2284170e72f485ebb586c7bd784f294475c25e5e
fmt/7.1.3: Copying sources to build folder
fmt/7.1.3: Building your package in /Users/near/.conan/data/fmt/7.1.3/_/_/build/2284170e72f485ebb586c7bd784f294475c25e5e
fmt/7.1.3: Generator cmake created conanbuildinfo.cmake
fmt/7.1.3: Calling build()
-- The C compiler identification is AppleClang 12.0.0.12000032
-- The CXX compiler identification is AppleClang 12.0.0.12000032
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working C compiler: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/cc - skipped
-- Detecting C compile features
-- Detecting C compile features - done
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/c++ - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Conan: called by CMake conan helper
-- Conan: called inside local cache
-- Conan: Adjusting output directories
-- Conan: Using cmake global configuration
-- Conan: Adjusting default RPATHs Conan policies
-- Conan: Adjusting language standard
-- Conan: Adjusting fPIC flag (ON)
-- Conan: Compiler Clang>=8, checking major version 11
-- Conan: Checking correct version: 12
CMake Error at conanbuildinfo.cmake:402 (message):
  Detected a mismatch for the compiler version between your conan profile
  settings and CMake:

  Compiler version specified in your conan profile: 11

  Compiler version detected in CMake: 12.0

  Please check your conan profile settings (conan profile show
  [default|your_profile_name])

  P.S.  You may set CONAN_DISABLE_CHECK_COMPILER CMake variable in order to
  disable this check.
Call Stack (most recent call first):
  conanbuildinfo.cmake:499 (conan_error_compiler_version)
  conanbuildinfo.cmake:589 (check_compiler_version)
  conanbuildinfo.cmake:141 (conan_check_compiler)
  CMakeLists.txt:5 (conan_basic_setup)


-- Configuring incomplete, errors occurred!
See also "/Users/near/.conan/data/fmt/7.1.3/_/_/build/2284170e72f485ebb586c7bd784f294475c25e5e/build_subfolder/CMakeFiles/CMakeOutput.log".
See also "/Users/near/.conan/data/fmt/7.1.3/_/_/build/2284170e72f485ebb586c7bd784f294475c25e5e/build_subfolder/CMakeFiles/CMakeError.log".
fmt/7.1.3: 
fmt/7.1.3: ERROR: Package '2284170e72f485ebb586c7bd784f294475c25e5e' build failed
fmt/7.1.3: WARN: Build folder /Users/near/.conan/data/fmt/7.1.3/_/_/build/2284170e72f485ebb586c7bd784f294475c25e5e
ERROR: fmt/7.1.3: Error in build() method, line 63
    cmake = self._configure_cmake()
while calling '_configure_cmake', line 56
    self._cmake.configure(build_folder=self._build_subfolder)
    ConanException: Error 1 while executing cd '/Users/near/.conan/data/fmt/7.1.3/_/_/build/2284170e72f485ebb586c7bd784f294475c25e5e/build_subfolder' && cmake -G "Unix Makefiles" -DCMAKE_BUILD_TYPE="Debug" -DCMAKE_OSX_ARCHITECTURES="x86_64" -DCMAKE_OSX_SYSROOT="/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX11.1.sdk" -DCONAN_IN_LOCAL_CACHE="ON" -DCONAN_COMPILER="clang" -DCONAN_COMPILER_VERSION="11" -DCONAN_CXX_FLAGS="-m64" -DCONAN_SHARED_LINKER_FLAGS="-m64" -DCONAN_C_FLAGS="-m64" -DCONAN_LIBCXX="libstdc++" -DBUILD_SHARED_LIBS="OFF" -DCMAKE_INSTALL_PREFIX="/Users/near/.conan/data/fmt/7.1.3/_/_/package/2284170e72f485ebb586c7bd784f294475c25e5e" -DCMAKE_INSTALL_BINDIR="bin" -DCMAKE_INSTALL_SBINDIR="bin" -DCMAKE_INSTALL_LIBEXECDIR="bin" -DCMAKE_INSTALL_LIBDIR="lib" -DCMAKE_INSTALL_INCLUDEDIR="include" -DCMAKE_INSTALL_OLDINCLUDEDIR="include" -DCMAKE_INSTALL_DATAROOTDIR="share" -DCONAN_CMAKE_POSITION_INDEPENDENT_CODE="ON" -DCMAKE_EXPORT_NO_PACKAGE_REGISTRY="ON" -DCONAN_EXPORTED="1" -DFMT_DOC="False" -DFMT_TEST="False" -DFMT_INSTALL="True" -DFMT_LIB_DIR="lib" -Wno-dev '/Users/near/.conan/data/fmt/7.1.3/_/_/build/2284170e72f485ebb586c7bd784f294475c25e5e'
"/Users/near/Library/Application Support/JetBrains/Toolbox/apps/CLion/ch-0/203.7717.62/CLion.app/Contents/bin/cmake/mac/bin/cmake" -DCMAKE_BUILD_TYPE=Debug -DCMAKE_CXX_COMPILER=clang++ -G "CodeBlocks - Unix Makefiles" /Users/near/Code/personal/blight
-- The CXX compiler identification is Clang 11.1.0
-- Check for working CXX compiler: /usr/local/opt/llvm/bin/clang++
-- Check for working CXX compiler: /usr/local/opt/llvm/bin/clang++ - works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Conan: Adjusting output directories
-- Conan: Using cmake global configuration
-- Conan: Adjusting default RPATHs Conan policies
-- Conan: Adjusting language standard
-- Current conanbuildinfo.cmake directory: /Users/near/Code/personal/blight/cmake-build-debug
CMake Error at cmake-build-debug/conanbuildinfo.cmake:626 (message):
  Detected a mismatch for the compiler version between your conan profile
  settings and CMake:

  Compiler version specified in your conan profile: 12.0

  Compiler version detected in CMake: 11.1

  Please check your conan profile settings (conan profile show
  [default|your_profile_name])

  P.S.  You may set CONAN_DISABLE_CHECK_COMPILER CMake variable in order to
  disable this check.
Call Stack (most recent call first):
  cmake-build-debug/conanbuildinfo.cmake:728 (conan_error_compiler_version)
  cmake-build-debug/conanbuildinfo.cmake:813 (check_compiler_version)
  cmake-build-debug/conanbuildinfo.cmake:365 (conan_check_compiler)
  CMakeLists.txt:13 (conan_basic_setup)


-- Configuring incomplete, errors occurred!
See also "/Users/near/Code/personal/blight/cmake-build-debug/CMakeFiles/CMakeOutput.log".

This is the output seen in the CMake output window of CLion. The first invocation has CMake think Apple-clang is my compiler while conan is configured to use the llvm version and on the second step (most likely invoked by conan_basic_setup in my CMakeLists.txt) the correct CMake compiler is chosen but Conan ends up without a profile hence a version mismatch.

In the CLion settings I have already overwritten the c++ compiler with the llvm v11.1 compiler:

What's the correct solution to properly configure both to use the llvm v11.1 compiler? I personally do not want to enable the CONAN_DISABLE_CHECK_COMPILER CMake variable as it is unclear which compiler will be used to compile dependencies in the end.

Previously posted questions only suggest intentionally using the higher version which is not what I want:

• CMake Error: mismatch for the compiler version between your conan profile

Answer 1

I was able to find a solution albeit by disabling the Conan integration first. With a clean build directory I went in there and had to invoke Conan manually as follows:

CC=clang CXX=clang++ conan install .. -pr=LLVM11Debug --build=missing

Afterwards it was possible run build with CMake and clang 11 configured in the UI of CLion. The issue was that the Conan integration plugin does not provide a direct way to set the compiler using the environment variables and it does not get the compiler from the Toolchain options in CLion.