One-click install: macOS and Linux wheels with a pip-installable Qt viewer

.gitignore

@@ -1,4 +1,5 @@
 _version.py
+.DS_Store
 
 # Byte-compiled / optimized / DLL files
 __pycache__/
@@ -124,6 +125,7 @@ celerybeat.pid
 # Environments
 .env
 .venv
+.venv-test/
 env/
 venv/
 ENV/

CMakeLists.txt

@@ -1,10 +1,12 @@
 cmake_minimum_required(VERSION 3.25...3.30)
+# CMP0169 only exists from CMake 3.30; older versions already behave as OLD.
+if (POLICY CMP0169)
+    cmake_policy(SET CMP0169 OLD)
+endif ()
 
 set(CMAKE_CXX_STANDARD 17)
-
 set(AWKWARD_VERSION "v2.6.9")
 set(PYBIND11_VERSION "v2.13.6")
-set(Geant4_VERSION "11.2.2")
 
 if (NOT DEFINED SKBUILD_PROJECT_NAME)
     # IDE
@@ -14,6 +16,11 @@ endif ()
 project(${SKBUILD_PROJECT_NAME} LANGUAGES CXX)
 
 set(PYTHON_MODULE_NAME _geant4_application)
+set(VIS_MODULE_NAME _geant4_vis)
+option(
+    GEANT4_PYTHON_APPLICATION_VISUALIZATION
+    "Build the interactive Geant4 Qt viewer as a separate, lazily imported module"
+    OFF)
 
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 set(CMAKE_CXX_EXTENSIONS OFF)
@@ -23,18 +30,26 @@ find_package(
     COMPONENTS Interpreter Development.Module
     REQUIRED)
 
-# define geant4 components in a conditional way, "gdml static" if release build,
-# "gdml" otherwise
-set(GEANT4_COMPONENTS "gdml")
-if (CMAKE_BUILD_TYPE STREQUAL "Release")
-    set(GEANT4_COMPONENTS "gdml static")
+if (GEANT4_PYTHON_APPLICATION_VISUALIZATION)
+    # The viewer module and the physics module must share one Geant4 (its
+    # managers are singletons), which only works with shared libraries.
+    find_package(Geant4 11.2.2 CONFIG REQUIRED COMPONENTS gdml ui_all vis_all)
+    if (NOT Geant4_shared_FOUND)
+        message(
+            FATAL_ERROR
+                "GEANT4_PYTHON_APPLICATION_VISUALIZATION requires Geant4 built with shared libraries"
+        )
+    endif ()
+else ()
+    # "static" is optional: Geant4Config fails if it is required but only shared
+    # libraries are installed, while as an optional component it still selects
+    # the static libraries whenever they exist.
+    find_package(
+        Geant4 11.2.2 CONFIG REQUIRED
+        COMPONENTS gdml
+        OPTIONAL_COMPONENTS static)
 endif ()
 
-find_package(
-    Geant4 ${Geant4_VERSION} CONFIG
-    COMPONENTS ${GEANT4_COMPONENTS}
-    REQUIRED)
-
 message(STATUS "Using Geant4 ${Geant4_VERSION} from ${Geant4_DIR}")
 message(STATUS "Using Python ${Python_VERSION} from ${Python_EXECUTABLE}")
 
@@ -46,7 +61,9 @@ FetchContent_Declare(
 )
 FetchContent_GetProperties(awkward-headers)
 if (NOT awkward-headers_POPULATED)
-    FetchContent_MakeAvailable(awkward-headers)
+    FetchContent_Populate(awkward-headers)
+    add_subdirectory(${awkward-headers_SOURCE_DIR}
+                     ${awkward-headers_BINARY_DIR} EXCLUDE_FROM_ALL)
 endif ()
 
 FetchContent_Declare(
@@ -56,15 +73,42 @@ FetchContent_Declare(
     DOWNLOAD_EXTRACT_TIMESTAMP 1)
 FetchContent_GetProperties(pybind11)
 if (NOT pybind11_POPULATED)
-    FetchContent_MakeAvailable(pybind11)
+    FetchContent_Populate(pybind11)
+    add_subdirectory(${pybind11_SOURCE_DIR} ${pybind11_BINARY_DIR}
+                     EXCLUDE_FROM_ALL)
 endif ()
 
+# Geant4 libraries that link Qt directly, or reach it through each other (the
+# visualization drivers, UI sessions and vis manager). The physics module must
+# not link any of them, so that importing the package never loads Qt.
+set(GEANT4_QT_LIBRARIES
+    G4OpenGL
+    G4ToolsSG
+    G4interfaces
+    G4visQt3D
+    G4vis_management
+    G4FR
+    G4GMocren
+    G4RayTracer
+    G4Tree
+    G4VRML
+    G4visHepRep
+    G4OpenInventor
+    G4visVtk)
+set(GEANT4_PHYSICS_LIBRARIES ${Geant4_LIBRARIES})
+foreach (lib IN LISTS GEANT4_QT_LIBRARIES)
+    list(REMOVE_ITEM GEANT4_PHYSICS_LIBRARIES Geant4::${lib}
+         Geant4::${lib}-static)
+endforeach ()
+
 file(GLOB_RECURSE SOURCES CONFIGURE_DEPENDS
      "${PROJECT_SOURCE_DIR}/src/geant4_application/src/*.cpp")
 
 file(GLOB_RECURSE PYTHON_SOURCES CONFIGURE_DEPENDS
      "${PROJECT_SOURCE_DIR}/src/python/*.cpp")
 
+get_filename_component(GEANT4_PREFIX "${Geant4_DIR}/../../.." ABSOLUTE)
+
 pybind11_add_module(${PYTHON_MODULE_NAME} MODULE ${SOURCES} ${PYTHON_SOURCES})
 
 target_compile_definitions(
@@ -81,23 +125,62 @@ target_include_directories(
             ${Geant4_INCLUDE_DIRS})
 
 target_link_libraries(
-    ${PYTHON_MODULE_NAME} PRIVATE ${Geant4_LIBRARIES} awkward::layout-builder
-                                  pybind11::headers)
+    ${PYTHON_MODULE_NAME} PRIVATE ${GEANT4_PHYSICS_LIBRARIES}
+                                  awkward::layout-builder pybind11::headers)
+
+set(EXTENSION_MODULES ${PYTHON_MODULE_NAME})
+
+if (GEANT4_PYTHON_APPLICATION_VISUALIZATION)
+    pybind11_add_module(${VIS_MODULE_NAME} MODULE
+                        "${PROJECT_SOURCE_DIR}/src/vis/module.cpp")
+    # Leave out Geant4's Qt3D driver: the PyQt5-Qt5 wheel that provides Qt to
+    # published wheels ships no Qt3D modules. Not linking Geant4::G4visQt3D also
+    # drops its G4VIS_USE_QT3D define, so G4VisExecutive never references it.
+    # The OpenGL Qt viewer (/vis/open OGL) is unaffected.
+    set(GEANT4_VIS_LIBRARIES ${Geant4_LIBRARIES})
+    list(REMOVE_ITEM GEANT4_VIS_LIBRARIES Geant4::G4visQt3D)
+    target_include_directories(${VIS_MODULE_NAME}
+                               PRIVATE ${Geant4_INCLUDE_DIRS})
+    target_link_libraries(${VIS_MODULE_NAME} PRIVATE ${GEANT4_VIS_LIBRARIES}
+                                                     pybind11::headers)
+    # Homebrew may expose Qt 6 from its global include directory while this
+    # Geant4 installation was built with Qt 5. Put Qt 5's forwarding headers
+    # first so framework headers do not accidentally include their Qt 6 peers.
+    if (APPLE AND DEFINED Qt5Core_DIR)
+        get_filename_component(QT5_PREFIX "${Qt5Core_DIR}/../../.." ABSOLUTE)
+        target_include_directories(${VIS_MODULE_NAME} SYSTEM BEFORE
+                                   PRIVATE "${QT5_PREFIX}/include")
+    endif ()
+    list(APPEND EXTENSION_MODULES ${VIS_MODULE_NAME})
+endif ()
 
-pybind11_extension(${PYTHON_MODULE_NAME})
-if (NOT MSVC AND NOT ${CMAKE_BUILD_TYPE} MATCHES Debug|RelWithDebInfo)
-    # Strip unnecessary sections of the binary on Linux/macOS
-    pybind11_strip(${PYTHON_MODULE_NAME})
+# Wheel repair tools (delocate/auditwheel) replace these with the bundled
+# library locations; source installs keep finding Geant4 where it was built. Qt
+# frameworks linked by @rpath (as when building against PyQt5-Qt5's Qt) also
+# need their directory listed for delocate to resolve them.
+set(EXTENSION_RPATH "${GEANT4_PREFIX}/lib")
+if (APPLE AND DEFINED QT5_PREFIX)
+    list(APPEND EXTENSION_RPATH "${QT5_PREFIX}/lib")
 endif ()
 
-set_target_properties(
-    ${PYTHON_MODULE_NAME}
-    PROPERTIES LIBRARY_OUTPUT_DIRECTORY ${PROJECT_BINARY_DIR}/${PROJECT_NAME}
-               CXX_VISIBILITY_PRESET "hidden"
-               CUDA_VISIBILITY_PRESET "hidden")
+foreach (module IN LISTS EXTENSION_MODULES)
+    pybind11_extension(${module})
+    if (NOT MSVC AND NOT ${CMAKE_BUILD_TYPE} MATCHES Debug|RelWithDebInfo)
+        # Strip unnecessary sections of the binary on Linux/macOS
+        pybind11_strip(${module})
+    endif ()
+    set_target_properties(
+        ${module}
+        PROPERTIES LIBRARY_OUTPUT_DIRECTORY
+                   ${PROJECT_BINARY_DIR}/${PROJECT_NAME}
+                   CXX_VISIBILITY_PRESET "hidden"
+                   CUDA_VISIBILITY_PRESET "hidden"
+                   BUILD_RPATH "${EXTENSION_RPATH}"
+                   INSTALL_RPATH "${EXTENSION_RPATH}")
+endforeach ()
 
 install(
-    TARGETS ${PYTHON_MODULE_NAME}
+    TARGETS ${EXTENSION_MODULES}
     LIBRARY DESTINATION ${PROJECT_NAME}
     RUNTIME DESTINATION ${PROJECT_NAME}
     ARCHIVE DESTINATION ${PROJECT_NAME})