Using find_package(botan) with botan 3.4.0 installed from conan

[marty1885]

Hi,

I'm trying to get Botan link to my program via conan. I noticed since 3.3.0 Botan comes with botan-config.cmake so I would expect find_package would be able to find Botan once installed. But I get the error

-- Check for working CXX compiler: C:/Program Files/Microsoft Visual Studio/2022/Community/VC/Tools/MSVC/14.37.32822/bin/Hostx64/x64/cl.exe - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
CMake Error at CMakeLists.txt:4 (find_package):
  By not providing "Findbotan.cmake" in CMAKE_MODULE_PATH this project has
  asked CMake to find a package configuration file provided by "botan", but
  CMake did not find one.

  Could not find a package configuration file provided by "botan" with any of
  the following names:

    botanConfig.cmake
    botan-config.cmake

  Add the installation prefix of "botan" to CMAKE_PREFIX_PATH or set
  "botan_DIR" to a directory containing one of the above files.  If "botan"
  provides a separate development package or SDK, be sure it has been
  installed.


-- Configuring incomplete, errors occurred!

Here is a minimal reproducible example: https://gist.github.com/marty1885/0438c66d3105c52ffd3508e18e00fb93
To reproduce

mkdir build
cd build
conan install .. -s compiler.cppstd=20 --output-folder=.
cmake .. -G "Visual Studio 17 2022" -T host=x64 -A x64 -DCMAKE_TOOLCHAIN_FILE="conan_toolchain.cmake"

OS: Windows
Compiler: MSVC

[reneme]

Thanks for the minimal example. I'll look into it tomorrow.

For now: the CMake config shipped with Botan isn't integrated with Conan. Frankly, I'm not even sure it should be. But that's just guess work on my side.

[marty1885]

Thanks. I need a universal way to use botan no matter if it's installed from conan or a system package.

[reneme]

For the record: This doesn't work neither on Windows nor on Linux.
The conan package does install the cmake config files (in .conan2/.../lib/cmake/Botan-3.4.0) but cmake is not picking it up from there.

[reneme]

From this conan documention page I understand that it is possible but not advised to redirect to package-provided *-config.cmake files. Apparently this may break compatibility with other non-cmake build systems and also is not compatible with multi-configuration builds. Instead, they suggest to combine the CMakeToolchain and CMakeDeps conan generators.

Unfortunately, I didn't use conan to consume packages recently. So any thoughts and feedback is appreciated.