Set FMT_USE_MODULES again

Refactory the CMakeLists.txt files

Fix build problems with test module fmt

Try to fix CI problems too

.CMakeUserPresets.json

@@ -65,7 +65,8 @@
       "name": "dev",
       "configurePreset": "dev",
       "configuration": "Release",
-      "jobs": 12,
+      "jobs": 1,
+      "verbose": true,
       "targets": [
         "install"
       ]

CMakeLists.txt

@@ -5,7 +5,9 @@ include(cmake/prelude.cmake)
 
 # Set experimental flag to enable `import std` support from CMake.
 # This must be enabled before C++ language support.
-# TODO: set(CMAKE_EXPERIMENTAL_CXX_IMPORT_STD 0e5b6991-d74f-4b3d-a41c-cf096e0b2508)
+if(CMAKE_CXX_SCAN_FOR_MODULES)
+  set(CMAKE_EXPERIMENTAL_CXX_IMPORT_STD 0e5b6991-d74f-4b3d-a41c-cf096e0b2508)
+endif()
 
 project(fmt
         VERSION 11.1.1.1
@@ -16,33 +18,28 @@ project(fmt
 
 include(cmake/variables.cmake)
 
-if(CMAKE_BUILD_TYPE STREQUAL Release)
-  include(cmake/example.cmake)
-endif()
-
 set(CMAKE_CXX_STANDARD 23)
 set(CMAKE_CXX_EXTENSIONS ON)
-set(CMAKE_CXX_STANDARD_REQUIRED YES)
+set(CMAKE_CXX_SCAN_FOR_MODULES ON)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
 
 set(CMAKE_DEBUG_POSTFIX D)
 # to prevent -Winclude-angled-in-module-purview in fmt/os.h
 # see /Users/clausklein/.cache/CPM/fmt/297020319ba1d5d14e1599714def59a1788711c5/include/fmt/os.h:33
 set(CPPdefinitions FMT_USE_FCNTL=0)
 set(ADD_STDLIB_MODULES)
 
-option(FMT_SEPARATE_COMPILATION "build fmt lib too" ${PROJECT_IS_TOP_LEVEL})
-if(UNIX)
-  option(FMT_USE_MODULES "Export a CXX_MODULE fmt if possible" ${PROJECT_IS_TOP_LEVEL})
-endif()
-# TODO: option(FMT_IMPORT_STD "Import the module std" ${PROJECT_IS_TOP_LEVEL})
+option(FMT_SEPARATE_COMPILATION "build fmt lib too" ${CMAKE_CXX_SCAN_FOR_MODULES})
+option(FMT_USE_MODULES "Export a CXX_MODULE fmt if possible" ${CMAKE_CXX_SCAN_FOR_MODULES})
+option(FMT_IMPORT_STD "Import the module std" ${FMT_USE_MODULES})
 
 if(FMT_USE_MODULES)
   list(APPEND CPPdefinitions FMT_MODULE)
   # FIXME: NO! list(APPEND CPPdefinitions FMT_ATTACH_TO_GLOBAL_MODULE)
 
   if(APPLE)
-    if(CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL 19.0)
-      execute_process(OUTPUT_VARIABLE LLVM_PREFIX COMMAND brew --prefix llvm@19 COMMAND_ECHO STDOUT)
+    if(CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL 20.0)
+      execute_process(OUTPUT_VARIABLE LLVM_PREFIX COMMAND brew --prefix llvm@20 COMMAND_ECHO STDOUT)
       string(STRIP ${LLVM_PREFIX} LLVM_PREFIX)
       message(STATUS "LLVM_PREFIX=${LLVM_PREFIX}")
 
@@ -62,16 +59,34 @@ if(FMT_USE_MODULES)
       add_link_options(-stdlib=libc++)
     endif()
 
-    # Tell CMake that we explicitly want `import std`.
-    # This will initialize the property on all targets declared after this to 1
-    if(CMAKE_CXX_COMPILER_IMPORT_STD)
-      set(CMAKE_CXX_MODULE_STD ON)
-    endif()
+    # Build the stdlib module
+    function(add_stdlib_module NAME)
+      add_library(${NAME})
+      # cmake-format: off
+      target_sources(${NAME} PUBLIC
+        FILE_SET CXX_MODULES
+        BASE_DIRS ${LLVM_LIBC_SOURCE}
+        FILES
+          ${LLVM_LIBC_SOURCE}/std.cppm
+          ${LLVM_LIBC_SOURCE}/std.compat.cppm
+      )
+      # cmake-format: on
+      target_compile_features(${NAME} PUBLIC cxx_std_23)
+      target_compile_definitions(${NAME} PUBLIC _LIBCPP_HAS_NO_LOCALIZATION)
+      target_compile_options(${NAME} PRIVATE -Wno-reserved-module-identifier)
+    endfunction()
 
-    if(CMAKE_CXX_MODULE_STD AND ADD_STDLIB_MODULES)
-      # FIXME: NO! list(APPEND CPPdefinitions FMT_IMPORT_STD)
-      list(APPEND CPPdefinitions HAS_STDLIB_MODULES)
-    endif()
+  endif()
+
+  # Tell CMake that we explicitly want `import std`.
+  # This will initialize the property on all targets declared after this to 1
+  if(CMAKE_CXX_COMPILER_IMPORT_STD)
+    set(CMAKE_CXX_MODULE_STD ON)
+  endif()
+
+  if(CMAKE_CXX_MODULE_STD OR ADD_STDLIB_MODULES)
+    # FIXME: NO! list(APPEND CPPdefinitions FMT_IMPORT_STD)
+    list(APPEND CPPdefinitions HAS_STDLIB_MODULES)
   endif()
 
   message(STATUS "CMAKE_CXX_COMPILER_IMPORT_STD=${CMAKE_CXX_COMPILER_IMPORT_STD}")
@@ -81,6 +96,10 @@ else()
   set(CMAKE_VERIFY_INTERFACE_HEADER_SETS ${PROJECT_IS_TOP_LEVEL})
 endif()
 
+if(CMAKE_EXPERIMENTAL_CXX_IMPORT_STD AND CMAKE_BUILD_TYPE STREQUAL Release)
+  include(cmake/example.cmake)
+endif()
+
 # ---- add dependency libraries ----
 
 include(cmake/CPM.cmake)
@@ -91,7 +110,7 @@ cpmaddpackage(
   GITHUB_REPOSITORY fmtlib/fmt
   GIT_TAG 11.1.1
   VERSION 11.1.1
-  DOWNLOAD_ONLY YES
+  DOWNLOAD_ONLY ON
 )
 # cmake-format: on
 
@@ -132,15 +151,14 @@ if(FMT_SEPARATE_COMPILATION)
     fmt PUBLIC FILE_SET public_headers TYPE HEADERS BASE_DIRS ${fmt_SOURCE_DIR}/include FILES ${_fmt_public_header}
   )
 
+  target_compile_definitions(fmt PUBLIC ${CPPdefinitions})
+  target_compile_options(fmt PUBLIC $<$<AND:$<COMPILE_LANGUAGE:CXX>,$<CXX_COMPILER_ID:MSVC>>:/utf-8>)
   target_compile_features(
     fmt INTERFACE "$<$<COMPILE_FEATURES:cxx_std_23>:cxx_std_23>" "$<$<NOT:$<COMPILE_FEATURES:cxx_std_23>>:cxx_std_20>"
   )
 
-  target_compile_options(fmt PUBLIC $<$<AND:$<COMPILE_LANGUAGE:CXX>,$<CXX_COMPILER_ID:MSVC>>:/utf-8>)
-
   if(FMT_USE_MODULES)
-    add_library(fmt::fmt-module ALIAS fmt)
-    target_compile_definitions(fmt PUBLIC ${CPPdefinitions})
+    add_library(fmt::fmt_module ALIAS fmt)
     # cmake-format: off
     target_sources(fmt PUBLIC
         FILE_SET public_modules
@@ -153,13 +171,12 @@ if(FMT_SEPARATE_COMPILATION)
     # cmake-format: on
   else()
     add_library(fmt::fmt ALIAS fmt)
-    set(CMAKE_CXX_SCAN_FOR_MODULES OFF)
-    target_compile_definitions(fmt PUBLIC ${CPPdefinitions})
-    target_sources(fmt PUBLIC ${_fmt_all_sources})
+    set_target_properties(fmt PROPERTIES CXX_SCAN_FOR_MODULES OFF)
+    target_sources(fmt PRIVATE ${_fmt_all_sources})
   endif()
 
   if(FMT_WARNINGS_AS_ERRORS AND FMT_DEVELOPER_MODE AND UNIX)
-    target_compile_options(fmt PUBLIC -Werror)
+    target_compile_options(fmt PRIVATE -Werror)
   endif()
 endif()
 

GNUmakefile

@@ -33,10 +33,10 @@ check: all
 
 test:
 	cmake --preset ci-${hostSystemName}
-	cmake --build build
+	cmake --build build -- -v -j 1
 	cmake --install build --prefix $(CURDIR)/stagedir
 	cmake -G Ninja -B build/tests -S tests -D CMAKE_PREFIX_PATH=$(CURDIR)/stagedir
-	cmake --build build/tests
+	cmake --build build/tests -- -v -j 1
 	ctest --test-dir build/tests
 
 example:

cmake/dev-mode.cmake

@@ -5,7 +5,11 @@ if(FMT_BUILD_TESTING)
   enable_testing()
 
   add_subdirectory(tests)
-  add_subdirectory(module/tests)
+
+  if(CMAKE_CXX_MODULE_STD)
+    add_subdirectory(module/tests)
+  endif()
+
 endif()
 
 option(FMT_BUILD_MCSS_DOCS "Build documentation using Doxygen and m.css" OFF)

cmake/install-rules.cmake

@@ -18,12 +18,13 @@ mark_as_advanced(FMT_INSTALL_CMAKEDIR)
 install(TARGETS fmt-header-only EXPORT fmtTargets FILE_SET HEADERS)
 
 if(FMT_USE_MODULES)
-  install(TARGETS fmt EXPORT fmtTargets FILE_SET public_headers FILE_SET public_modules
-          DESTINATION ${FMT_INSTALL_CMAKEDIR}/module
+  install(TARGETS fmt EXPORT fmtTargets FILE_SET public_headers #
+                                        FILE_SET public_modules DESTINATION ${FMT_INSTALL_CMAKEDIR}/module
   )
 else()
-  install(FILES module/fmt.cppm DESTINATION ${FMT_INSTALL_CMAKEDIR}/module)
+  install(TARGETS fmt EXPORT fmtTargets FILE_SET public_headers)
 endif()
+install(FILES module/fmt.cppm DESTINATION ${FMT_INSTALL_CMAKEDIR}/module)
 install(FILES ${_fmt_all_sources} DESTINATION ${FMT_INSTALL_CMAKEDIR}/module)
 
 write_basic_package_version_file("${_package}ConfigVersion.cmake" COMPATIBILITY SameMajorVersion ARCH_INDEPENDENT)

module/tests/CMakeLists.txt

@@ -13,6 +13,7 @@ if(PROJECT_IS_TOP_LEVEL)
   if(NOT CMAKE_CXX_STANDARD)
     set(CMAKE_CXX_STANDARD 23)
     set(CMAKE_CXX_EXTENSIONS ON)
+    set(CMAKE_CXX_SCAN_FOR_MODULES ON)
     set(CMAKE_CXX_STANDARD_REQUIRED ON)
   endif()
   if(CMAKE_GENERATOR STREQUAL "Ninja")
@@ -32,12 +33,8 @@ if(PROJECT_IS_TOP_LEVEL)
     message(STATUS "CMAKE_CXX_IMPLICIT_INCLUDE_DIRECTORIES=${CMAKE_CXX_IMPLICIT_INCLUDE_DIRECTORIES}")
   endif()
   if(USE_MODULES)
-    if(NOT CMAKE_CXX_COMPILER_IMPORT_STD AND ADD_STDLIB_MODULES)
-      message(WARNING "ADD_STDLIB_MODULES=${ADD_STDLIB_MODULES}")
-      add_stdlib_module(${ADD_STDLIB_MODULES})
-    endif()
     # Build the fmt module
-    add_fmt_module(fmt-module)
+    add_fmt_module(fmt_module)
   endif()
 endif()
 
@@ -48,9 +45,14 @@ message(STATUS "Module tests to be built: ${ALL_TESTS}")
 foreach(_file ${ALL_TESTS})
   add_executable(module_${_file})
   target_sources(module_${_file} PRIVATE ../../tests/${_file}.cc)
-  if(USE_MODULES)
-    target_link_libraries(module_${_file} fmt-module ${ADD_STDLIB_MODULES})
-    # XXX: NOT USED! target_compile_definitions(module_${_file} PUBLIC USE_MODULES)
+  if(CMAKE_CXX_MODULE_STD)
+    target_link_libraries(module_${_file} fmt_module)
+  elseif(ADD_STDLIB_MODULES)
+    if(NOT CMAKE_CXX_COMPILER_IMPORT_STD AND ADD_STDLIB_MODULES)
+      message(WARNING "ADD_STDLIB_MODULES=${ADD_STDLIB_MODULES}")
+      add_stdlib_module(${ADD_STDLIB_MODULES})
+    endif()
+    target_link_libraries(module_${_file} fmt_module ${ADD_STDLIB_MODULES})
   else()
     target_link_libraries(module_${_file} fmt::fmt-header-only)
   endif()

tests/CMakeLists.txt

@@ -10,8 +10,14 @@ include(../cmake/windows-set-path.cmake OPTIONAL)
 if(PROJECT_IS_TOP_LEVEL)
   enable_testing()
 
-  find_package(fmt 11.1.1.1 EXACT REQUIRED)
-  include(../cmake/CPM.cmake)
+  set(CMAKE_CXX_STANDARD 23)
+  set(CMAKE_CXX_EXTENSIONS ON)
+  set(CMAKE_CXX_SCAN_FOR_MODULES ON)
+  set(CMAKE_CXX_STANDARD_REQUIRED ON)
+
+  find_package(fmt 11.1.1.1 EXACT REQUIRED HINT ../stagedir/lib)
+
+  add_subdirectory(../module/tests module_test)
 endif()
 
 # ---- Tests ----
@@ -21,32 +27,20 @@ if(EXISTS ${fmt_SOURCE_DIR}/test/header-only-test.cc AND NOT EXISTS ${CMAKE_CURR
 endif()
 add_executable(header-only-test header-only-test.cc)
 
-# Build the stdlib module
-function(add_stdlib_module NAME)
-  add_library(${NAME})
-  # cmake-format: off
-  target_sources(${NAME} PUBLIC
-    FILE_SET CXX_MODULES
-    BASE_DIRS ${LLVM_LIBC_SOURCE}
-    FILES
-      ${LLVM_LIBC_SOURCE}/std.cppm
-      ${LLVM_LIBC_SOURCE}/std.compat.cppm
-  )
-  # cmake-format: on
-  target_compile_features(${NAME} PUBLIC cxx_std_23)
-  target_compile_definitions(${NAME} PUBLIC _LIBCPP_HAS_NO_LOCALIZATION)
-  target_compile_options(${NAME} PRIVATE -Wno-reserved-module-identifier)
-endfunction()
-
 if(FMT_USE_MODULES)
   # Build the stdlib modules if possible
   # /usr/local/Cellar/llvm/19.1.6/share/libc++/v1/std.cppm
   # /usr/local/Cellar/llvm/19.1.6/share/libc++/v1/std.compat.cppm
   if(NOT CMAKE_CXX_COMPILER_IMPORT_STD AND ADD_STDLIB_MODULES)
     message(WARNING "ADD_STDLIB_MODULES=${ADD_STDLIB_MODULES}")
     add_stdlib_module(${ADD_STDLIB_MODULES})
+    target_link_libraries(header-only-test ${ADD_STDLIB_MODULES})
+  endif()
+  if(TARGET fmt::fmt_module)
+    target_link_libraries(header-only-test fmt::fmt_module)
+  else()
+    target_link_libraries(header-only-test fmt::fmt)
   endif()
-  target_link_libraries(header-only-test ${ADD_STDLIB_MODULES} fmt::fmt-module)
 else()
   target_link_libraries(header-only-test fmt::fmt-header-only)
 endif()
@@ -80,8 +74,8 @@ if(NOT PROJECT_IS_TOP_LEVEL)
           "-DADD_STDLIB_MODULES=${ADD_STDLIB_MODULES}"
           "-DLLVM_LIBC_SOURCE=${LLVM_LIBC_SOURCE}"
           "-DLLVM_ROOT=${LLVM_ROOT}"
-          # TODO: "-DCMAKE_CXX_MODULE_STD=ON"
-          # TODO: "-DCMAKE_EXPERIMENTAL_CXX_IMPORT_STD=0e5b6991-d74f-4b3d-a41c-cf096e0b2508"
+          "-DCMAKE_CXX_MODULE_STD=${CMAKE_CXX_MODULE_STD}"
+          "-DCMAKE_EXPERIMENTAL_CXX_IMPORT_STD=${CMAKE_EXPERIMENTAL_CXX_IMPORT_STD}"
     )
   endif()
   # cmake-format: on