conan-center-index: [package] swig/4.0.2: find_package(SWIG) doesn't set SWIG_EXECUTABLE

Package and Environment Details (include every applicable attribute)

Package Name/Version: swig/4.0.2
Operating System+version: MacOS 11.6
Compiler+version: Apple Clang 12
Conan version: conan 1.47.0
Python version: Python 3.9.12

Conan profile (output of `conan profile show default` or `conan profile show <profile>` if custom profile is in use)

[settings]
os=Macos
os_build=Macos
arch=x86_64
arch_build=x86_64
compiler=apple-clang
compiler.version=12.0
compiler.libcxx=libc++
build_type=Release
[options]
[conf]
[build_requires]
[env]

Steps to reproduce (Include if Applicable)

conanfile.py

from conans import CMake, ConanFile, tools

class TestPackageConan(ConanFile):
    settings = "os", "arch", "compiler", "build_type"
    generators = "cmake_find_package"
    requires = "swig/4.0.2"

    def build(self):
        cmake = CMake(self)
        cmake.verbose = True
        cmake.configure()
        cmake.build()

CMakeLists.txt

cmake_minimum_required(VERSION 3.1)
project(Test)

set(CMAKE_MODULE_PATH ${CMAKE_BINARY_DIR} ${CMAKE_MODULE_PATH})
set(CMAKE_PREFIX_PATH ${CMAKE_BINARY_DIR} ${CMAKE_PREFIX_PATH})

find_package(SWIG REQUIRED)
include(UseSWIG)
message("SWIG_DIR: ${SWIG_DIR}")
message("SWIG_EXECUTABLE: ${SWIG_EXECUTABLE}")

if ("${SWIG_EXECUTABLE}" STREQUAL "" OR "${SWIG_EXECUTABLE}" STREQUAL "SWIG_EXECUTABLE-NOTFOUND")
    message(FATAL_ERROR "Didn't work.")
else()
    message("It looks like it worked? Check variables above and see if they make sense.")
endif()

add_executable(test main.cpp)

main.cpp

int main() { return 0; }

If I build this the usual way, it’s unable to find the SWIG executable. However, if I build it as if it were a test package, it correctly populates SWIG_DIR, SWIG_EXECUTABLE, etc. I’ve tried this with and without the cmake generator, tried it with cmake_find_package_multi, CMakeDeps, etc, and nothing works.

Logs (Include/Attach if Applicable)

conan test . swig/4.0.2@

SWIG_DIR: /Users/developer/.conan/data/swig/4.0.2/_/_/package/099d7b9cd06e9bd11e92b9a2ddf3b29cd986fdcb/bin/swig/swiglib
SWIG_EXECUTABLE: /Users/developer/.conan/data/swig/4.0.2/_/_/package/099d7b9cd06e9bd11e92b9a2ddf3b29cd986fdcb/bin/swig

mkdir build && cd build && conan install .. && cmake ..

SWIG_DIR: 
SWIG_EXECUTABLE: SWIG_EXECUTABLE-NOTFOUND

About this issue

Original URL
State: open
Created 2 years ago
Comments: 15 (11 by maintainers)

Most upvoted comments

find_package(SWIG)

only works when the PATH is configured correctly. When you would run the following commands, it will build correctly:

mkdir build && cd build
conan install ..
conan build ..

If you don’t want conan to drive the compilation, you need modify your environment. This can be done with the virtualrunenv generator. Modify you conanfile.py slightly:

from conans import CMake, ConanFile, tools

class TestPackageConan(ConanFile):
    settings = "os", "arch", "compiler", "build_type"
    generators = "cmake_find_package", "virtualrunenv"
    requires = "swig/4.0.2"

    def build(self):
        cmake = CMake(self)
        cmake.verbose = True
        cmake.configure()
        cmake.build()

Then, you can do the following:

mkdir build && cd build
conan install ..
. activate_run.sh
cmake ..

madebr on Apr 22, 2022