Only fetch XTensor if needed

.gitlab-ci.yml

@@ -98,17 +98,18 @@ format:
 clang-tidy:
   extends: .needs-2204
   stage: linting
+  variables:
+    CLANG_TIDY_FIXES: clang-tidy-fixes.yml
   before_script:
     - git clone https://gitlab.com/aroffringa/aocommon.git
   script:
-    - export CLANG_TIDY_FIXES=clang-tidy-fixes.yml
     - mkdir build && cd build
     - cmake -DAOCOMMON_INCLUDE_DIR=../aocommon/include -DCLANG_TIDY_FIXES_FILE=${CLANG_TIDY_FIXES} -DCLANG_TIDY_WERROR=ON -DBUILD_TESTING=ON ..
     - make check-clang-tidy
   artifacts:
     when: on_failure
     paths:
-      - build/clang-tidy-fixes.yml
+      - build/${CLANG_TIDY_FIXES}
 
 .build:
   stage: build

CMakeLists.txt

@@ -44,10 +44,20 @@ add_compile_options(
   -Wextra
   -Wno-unused-parameter)
 
+# Let schaapcommon be a STATIC library, to reduce the risk on linking problems
+add_library(schaapcommon STATIC "")
+
+find_package(Threads REQUIRED)
+target_link_libraries(${SCHAAPCOMMON_PROJECT_NAME} Threads::Threads)
+
 # Convenience conditional to distinguish between stand-alone vs dependency builds
-set(SCHAAPCOMMON_MASTER_PROJECT OFF)
-if(CMAKE_CURRENT_SOURCE_DIR STREQUAL CMAKE_SOURCE_DIR)
-  set(SCHAAPCOMMON_MASTER_PROJECT ON)
+if(${CMAKE_CURRENT_SOURCE_DIR} STREQUAL ${CMAKE_SOURCE_DIR})
+  set(SCHAAPCOMMON_MASTER_PROJECT TRUE)
+else()
+  set(SCHAAPCOMMON_MASTER_PROJECT FALSE)
+endif()
+
+if(SCHAAPCOMMON_MASTER_PROJECT)
   set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
   set(CLANG_TIDY_EXE
       "clang-tidy"
@@ -56,9 +66,18 @@ if(CMAKE_CURRENT_SOURCE_DIR STREQUAL CMAKE_SOURCE_DIR)
       ""
       CACHE STRING "Write clang-tidy fixes to yml file with specified name.")
   option(CLANG_TIDY_WERROR OFF)
-endif()
+  if(CLANG_TIDY_WERROR)
+    set(CLANG_TIDY_WARNINGS_AS_ERRORS "*")
+  endif()
+
+  file(GLOB_RECURSE ALL_CXX_SOURCE_FILES ${CMAKE_SOURCE_DIR}/src/*.cc)
+  add_custom_target(
+    check-clang-tidy
+    COMMAND
+      ${CLANG_TIDY_EXE} --export-fixes=${CLANG_TIDY_FIXES_FILE}
+      --warnings-as-errors=${CLANG_TIDY_WARNINGS_AS_ERRORS} -p .
+      ${ALL_CXX_SOURCE_FILES})
 
-if(SCHAAPCOMMON_MASTER_PROJECT)
   # Require AOCOMMON when compiled in standalone.
   set(AOCOMMON_INCLUDE_DIR
       ""
@@ -89,41 +108,18 @@ if(SCHAAPCOMMON_MASTER_PROJECT)
       REQUIRED)
   endif()
 else()
-  include("${CMAKE_SOURCE_DIR}/external/aocommon/CMake/FetchXTensor.cmake")
-endif()
-
-# Compile in release mode if schaapcommon is included from external
-# dependency
-if(NOT SCHAAPCOMMON_MASTER_PROJECT)
-  set(CMAKE_BUILD_TYPE Release)
-endif()
-
-# Let schaapcommon be a STATIC library, to reduce the risk on linking problems
-add_library(schaapcommon STATIC "")
-
-find_package(Threads REQUIRED)
-target_link_libraries(${SCHAAPCOMMON_PROJECT_NAME} Threads::Threads)
-
-if(SCHAAPCOMMON_MASTER_PROJECT)
-  if(CMAKE_EXPORT_COMPILE_COMMANDS)
-    if(CLANG_TIDY_WERROR)
-      set(CLANG_TIDY_WARNINGS_AS_ERRORS "*")
-    endif()
-
-    file(GLOB_RECURSE ALL_CXX_SOURCE_FILES ${CMAKE_SOURCE_DIR}/src/*.cc)
-    add_custom_target(
-      check-clang-tidy
-      COMMAND
-        ${CLANG_TIDY_EXE} --export-fixes=${CLANG_TIDY_FIXES_FILE}
-        --warnings-as-errors=${CLANG_TIDY_WARNINGS_AS_ERRORS} -p .
-        ${ALL_CXX_SOURCE_FILES})
+  # Projects using schaapcommon and XTensor should include FetchXTensor.cmake
+  # *before* schaapcommon, since:
+  # - FetchXTensor.cmake should apply compiler directives to the entire project.
+  # - FetchXTensor.cmake does not support duplicate inclusion.
+
+  # Fetch XTensor if it has not been fetched before.
+  if(NOT TARGET xtensor)
+    include(${CMAKE_SOURCE_DIR}/external/aocommon/CMake/FetchXTensor.cmake)
   endif()
 
-  # Install targets
-  install(
-    TARGETS schaapcommon
-    ARCHIVE DESTINATION lib
-    LIBRARY DESTINATION lib)
+  # Compile in release mode if schaapcommon is included as external dependency.
+  set(CMAKE_BUILD_TYPE Release)
 endif()
 
 # For backwards compatibility: Build everything if SCHAAPCOMMON_MODULES is unset.