Add CMake flags gating Tracking and DCHdigi

CMakeLists.txt

@@ -16,6 +16,15 @@ set(${PackageName}_VERSION "${PACKAGE_VERSION_MAJOR}.${PACKAGE_VERSION_MINOR}.${
 # Let CMake know where to find FindXXX.cmake files
 set(CMAKE_MODULE_PATH ${CMAKE_CURRENT_SOURCE_DIR}/cmake)
 
+# The Tracking subpackage targets FCCee and pulls in dependencies that are not
+# available everywhere (GenFit, MarlinUtil, PandoraSDK, ONNX Runtime, Torch).
+# Turn this off to build only the digitizers, e.g. on the Muon Collider stack.
+option(K4RECTRACKER_TRACKING "Build the Tracking subpackage" ON)
+
+# The DCH digitisers need Delphes (DCHdigi_v02) and GSL, and build the podio
+# datamodel extension used for drift chamber hits.
+option(K4RECTRACKER_DCH_DIGITISERS "Build the DCH digitisers" ON)
+
 # dependencies
 # For some reason, the find_package with DD4hep must be the first one
 find_package(DD4hep REQUIRED COMPONENTS DDRec DDG4 DDParsers)
@@ -29,13 +38,23 @@ find_package(EDM4HEP REQUIRED)
 find_package(k4FWCore 1.3 REQUIRED)
 find_package(k4geo REQUIRED)
 find_package(Gaudi REQUIRED)
-find_package(Delphes REQUIRED)
-find_package(GSL REQUIRED)
-find_package(PandoraSDK REQUIRED)
-find_package(Eigen3 REQUIRED)
+# Needed by the DCH digitisers and by Tracking
+if(K4RECTRACKER_DCH_DIGITISERS OR K4RECTRACKER_TRACKING)
+  find_package(Delphes REQUIRED)
+endif()
+
+# Only needed by the DCH digitisers
+if(K4RECTRACKER_DCH_DIGITISERS)
+  find_package(GSL REQUIRED)
+endif()
 
-find_package(onnxruntime REQUIRED)
-find_package(Torch REQUIRED)
+# Only needed by Tracking
+if(K4RECTRACKER_TRACKING)
+  find_package(PandoraSDK REQUIRED)
+  find_package(Eigen3 REQUIRED)
+  find_package(onnxruntime REQUIRED)
+  find_package(Torch REQUIRED)
+endif()
 
 include(cmake/Key4hepConfig.cmake)
 
@@ -53,11 +72,19 @@ function(set_test_env _testname)
 
 endfunction()
 
-add_subdirectory(DCHdigi)
+if(K4RECTRACKER_DCH_DIGITISERS)
+  add_subdirectory(DCHdigi)
+else()
+  message(STATUS "K4RECTRACKER_DCH_DIGITISERS is OFF: not building the DCH digitisers")
+endif()
 add_subdirectory(ARCdigi)
 add_subdirectory(VTXdigi)
 add_subdirectory(VTXdigiDetailed)
-set(CMAKE_MODULE_PATH ${CMAKE_CURRENT_SOURCE_DIR}/cmake ${CMAKE_MODULE_PATH})
-add_subdirectory(Tracking)
+if(K4RECTRACKER_TRACKING)
+  set(CMAKE_MODULE_PATH ${CMAKE_CURRENT_SOURCE_DIR}/cmake ${CMAKE_MODULE_PATH})
+  add_subdirectory(Tracking)
+else()
+  message(STATUS "K4RECTRACKER_TRACKING is OFF: not building the Tracking subpackage")
+endif()
 
 include(cmake/CreateProjectConfig.cmake)

Tracking/CMakeLists.txt

@@ -38,7 +38,6 @@ gaudi_add_module(${PackageName}
   k4FWCore::k4FWCore
   k4FWCore::k4Interface
   k4geo::detectorCommon
-  extensionDict
   onnxruntime::onnxruntime
   torch
   DD4hep::DDRec
@@ -48,6 +47,11 @@ gaudi_add_module(${PackageName}
   ${DELPHES_LIBRARIES}
 )
 
+# The podio datamodel extension is built by DCHdigi
+if(TARGET extensionDict)
+  target_link_libraries(${PackageName} PRIVATE extensionDict)
+endif()
+
 if(TARGET PandoraPFA::PandoraSDK)
   target_link_libraries(${PackageName} PRIVATE PandoraPFA::PandoraSDK)
 endif()