Tests/CXXModules: split out compilation tests

The test is getting fairly large and timing out more and more often.
Split out actual compilation tests.

.gitlab/ci/ctest_exclusions.cmake

@@ -34,6 +34,7 @@ if ("$ENV{CMAKE_CONFIGURATION}" MATCHES "_valgrind")
     "^RunCMake.Autogen_Qt6_1$"
     "^RunCMake.GoogleTest$"
     "^RunCMake.CXXModules$"
+    "^RunCMake.CXXModulesCompile$"
     "^RunCMake.CommandLine$"
 
     # Too spurious under Valgrind.

Tests/RunCMake/CMakeLists.txt

@@ -833,11 +833,14 @@ set_property(TEST RunCMake.DependencyGraph APPEND PROPERTY LABELS "Fortran")
 
 # Add C++ Module tests.
 add_RunCMake_test(CXXModules
+  -DCMake_TEST_CXX_STDLIB_MODULES_JSON=${CMake_TEST_CXX_STDLIB_MODULES_JSON}
+)
+add_RunCMake_test(CXXModulesCompile
   -DCMake_TEST_MODULE_COMPILATION=${CMake_TEST_MODULE_COMPILATION}
   -DCMake_TEST_MODULE_COMPILATION_RULES=${CMake_TEST_MODULE_COMPILATION_RULES}
   -DCMake_TEST_CXX_STDLIB_MODULES_JSON=${CMake_TEST_CXX_STDLIB_MODULES_JSON}
 )
-set_property(TEST RunCMake.CXXModules APPEND
+set_property(TEST RunCMake.CXXModules RunCMake.CXXModulesCompile APPEND
   PROPERTY LABELS "CXXModules")
 
 # ctresalloc links against CMakeLib and CTestLib, which means it can't be built

Tests/RunCMake/CXXModules/RunCMakeTest.cmake

@@ -135,330 +135,3 @@ else ()
   message(FATAL_ERROR
     "Please add 'DependInfo' tests for the '${RunCMake_GENERATOR}' generator.")
 endif ()
-
-# Actual compilation tests.
-if (NOT CMake_TEST_MODULE_COMPILATION)
-  return ()
-endif ()
-
-function (run_cxx_module_test directory)
-  set(test_name "${directory}")
-  if (NOT ARGN STREQUAL "")
-    list(POP_FRONT ARGN test_name)
-  endif ()
-
-  set(RunCMake_TEST_SOURCE_DIR "${CMAKE_CURRENT_LIST_DIR}/examples/${directory}")
-  set(RunCMake_TEST_BINARY_DIR "${RunCMake_BINARY_DIR}/examples/${test_name}-build")
-
-  if (RunCMake_GENERATOR_IS_MULTI_CONFIG)
-    set(RunCMake_TEST_OPTIONS -DCMAKE_CONFIGURATION_TYPES=Debug)
-  else ()
-    set(RunCMake_TEST_OPTIONS -DCMAKE_BUILD_TYPE=Debug)
-  endif ()
-  if (directory MATCHES "import-std")
-    list(APPEND RunCMake_TEST_OPTIONS
-      ${stdlib_custom_json})
-  endif ()
-
-  if (RunCMake_CXXModules_INSTALL)
-    set(prefix "${RunCMake_BINARY_DIR}/examples/${test_name}-install")
-    file(REMOVE_RECURSE "${prefix}")
-    list(APPEND RunCMake_TEST_OPTIONS
-      "-DCMAKE_INSTALL_PREFIX=${prefix}")
-  endif ()
-
-  list(APPEND RunCMake_TEST_OPTIONS
-    "-DCMake_TEST_MODULE_COMPILATION_RULES=${CMake_TEST_MODULE_COMPILATION_RULES}"
-    ${ARGN})
-  run_cmake("examples/${test_name}")
-  set(RunCMake_TEST_NO_CLEAN 1)
-  if (RunCMake_CXXModules_TARGET)
-    run_cmake_command("examples/${test_name}-build" "${CMAKE_COMMAND}" --build . --config Debug --target "${RunCMake_CXXModules_TARGET}")
-  else ()
-    run_cmake_command("examples/${test_name}-build" "${CMAKE_COMMAND}" --build . --config Debug)
-    foreach (RunCMake_CXXModules_TARGET IN LISTS RunCMake_CXXModules_TARGETS)
-      set(RunCMake_CXXModules_CONFIG "Debug")
-      set(RunCMake_CXXModules_NAME_SUFFIX "")
-      if (RunCMake_CXXModules_TARGET MATCHES "(.*)@(.*)")
-        set(RunCMake_CXXModules_TARGET "${CMAKE_MATCH_1}")
-        set(RunCMake_CXXModules_CONFIG "${CMAKE_MATCH_2}")
-        set(RunCMake_CXXModules_NAME_SUFFIX "-${RunCMake_CXXModules_CONFIG}")
-      endif ()
-      run_cmake_command("examples/${test_name}-target-${RunCMake_CXXModules_TARGET}${RunCMake_CXXModules_NAME_SUFFIX}" "${CMAKE_COMMAND}" --build . --target "${RunCMake_CXXModules_TARGET}" --config "${RunCMake_CXXModules_CONFIG}")
-    endforeach ()
-  endif ()
-  if (RunCMake_CXXModules_INSTALL)
-    run_cmake_command("examples/${test_name}-install" "${CMAKE_COMMAND}" --build . --target install --config Debug)
-  endif ()
-  if (NOT RunCMake_CXXModules_NO_TEST)
-    run_cmake_command("examples/${test_name}-test" "${CMAKE_CTEST_COMMAND}" -C Debug --output-on-failure)
-  endif ()
-  if (RunCMake_CXXModules_REBUILD)
-    execute_process(COMMAND ${CMAKE_COMMAND} -E sleep 1.125) # handle 1s resolution
-    include("${RunCMake_TEST_SOURCE_DIR}/pre-rebuild.cmake")
-    execute_process(COMMAND ${CMAKE_COMMAND} -E sleep 1.125) # handle 1s resolution
-    run_cmake_command("examples/${test_name}-rebuild" "${CMAKE_COMMAND}" --build . --config Debug)
-  endif ()
-endfunction ()
-
-function (run_cxx_module_test_target directory target)
-  set(RunCMake_CXXModules_TARGET "${target}")
-  set(RunCMake_CXXModules_NO_TEST 1)
-  run_cxx_module_test("${directory}" ${ARGN})
-endfunction ()
-
-function (run_cxx_module_test_rebuild directory)
-  set(RunCMake_CXXModules_INSTALL 0)
-  set(RunCMake_CXXModules_NO_TEST 1)
-  set(RunCMake_CXXModules_REBUILD 1)
-  run_cxx_module_test("${directory}" ${ARGN})
-endfunction ()
-
-# Module compilation features:
-# Compiler-based:
-# - `named`: basic support for named modules is available
-# - `shared`: shared libraries are supported
-# - `partitions`: module partitions are supported
-# - `internal_partitions`: internal module partitions are supported
-# - `bmionly`: the compiler supports BMI-only builds
-# - `import_std23`: the compiler supports `import std` for C++23
-#
-# Generator-based:
-# - `compile_commands`: the generator supports `compile_commands.json`
-# - `collation`: the generator supports module collation features
-# - `export_bmi`: the generator supports exporting BMIs
-# - `ninja`: a `ninja` binary is available to perform `Ninja`-only testing
-#   (assumed if the generator matches `Ninja`).
-string(REPLACE "," ";" CMake_TEST_MODULE_COMPILATION "${CMake_TEST_MODULE_COMPILATION}")
-if (RunCMake_GENERATOR MATCHES "Ninja")
-  list(APPEND CMake_TEST_MODULE_COMPILATION
-    "ninja")
-endif ()
-
-if (RunCMake_GENERATOR MATCHES "Ninja")
-  if (RunCMake_GENERATOR_IS_MULTI_CONFIG)
-    set(ninja_cmp0154_target "CMakeFiles/ninja_cmp0154.dir/Debug/unrelated.cxx${CMAKE_CXX_OUTPUT_EXTENSION}")
-  else ()
-    set(ninja_cmp0154_target "CMakeFiles/ninja_cmp0154.dir/unrelated.cxx${CMAKE_CXX_OUTPUT_EXTENSION}")
-  endif ()
-  run_cxx_module_test_target(ninja-cmp0154 "${ninja_cmp0154_target}")
-endif ()
-
-run_cxx_module_test(scan-with-pch)
-
-# Tests which use named modules.
-if ("named" IN_LIST CMake_TEST_MODULE_COMPILATION)
-  run_cxx_module_test(simple)
-  run_cxx_module_test(file-sets-with-dot)
-  run_cxx_module_test(vs-without-flags)
-  run_cxx_module_test(library library-static -DBUILD_SHARED_LIBS=OFF)
-  run_cxx_module_test(unity-build)
-  run_cxx_module_test(object-library)
-  run_cxx_module_test(generated)
-  run_cxx_module_test(deep-chain)
-  run_cxx_module_test(non-trivial-collation-order)
-  run_cxx_module_test(non-trivial-collation-order-randomized)
-  run_cxx_module_test(duplicate)
-  set(RunCMake_CXXModules_NO_TEST 1)
-  run_cxx_module_test(import-from-object)
-  run_cxx_module_test(circular)
-  run_cxx_module_test(try-compile)
-  run_cxx_module_test(try-run)
-  unset(RunCMake_CXXModules_NO_TEST)
-  run_cxx_module_test(same-src-name)
-  run_cxx_module_test(scan_properties)
-  run_cxx_module_test(target-objects)
-
-  if ("cxx_std_23" IN_LIST CMAKE_CXX_COMPILE_FEATURES AND
-      "import_std23" IN_LIST CMake_TEST_MODULE_COMPILATION)
-    run_cxx_module_test(import-std)
-    set(RunCMake_CXXModules_NO_TEST 1)
-    run_cxx_module_test(import-std-no-std-property)
-    unset(RunCMake_CXXModules_NO_TEST)
-    run_cxx_module_test(import-std-export-no-std-build)
-    set(RunCMake_CXXModules_INSTALL 1)
-    run_cxx_module_test(import-std-export-no-std-install)
-    unset(RunCMake_CXXModules_INSTALL)
-
-    if ("collation" IN_LIST CMake_TEST_MODULE_COMPILATION)
-      run_cxx_module_test(import-std-not-in-export-build)
-      run_cxx_module_test(import-std-transitive import-std-transitive-not-in-export-build "-DCMAKE_PREFIX_PATH=${RunCMake_BINARY_DIR}/examples/import-std-not-in-export-build-build")
-
-      set(RunCMake_CXXModules_INSTALL 1)
-      run_cxx_module_test(import-std-not-in-export-install)
-      unset(RunCMake_CXXModules_INSTALL)
-      run_cxx_module_test(import-std-transitive import-std-transitive-not-in-export-install "-DCMAKE_PREFIX_PATH=${RunCMake_BINARY_DIR}/examples/import-std-not-in-export-install-install")
-
-      run_cxx_module_test(import-std-transitive import-std-transitive-export-no-std-build "-DCMAKE_PREFIX_PATH=${RunCMake_BINARY_DIR}/examples/import-std-export-no-std-build-build" -DEXPORT_NO_STD=1)
-      run_cxx_module_test(import-std-transitive import-std-transitive-export-no-std-install "-DCMAKE_PREFIX_PATH=${RunCMake_BINARY_DIR}/examples/import-std-export-no-std-install-install" -DEXPORT_NO_STD=1)
-    endif ()
-  endif ()
-endif ()
-
-# Tests which require compile commands support.
-if ("compile_commands" IN_LIST CMake_TEST_MODULE_COMPILATION)
-  run_cxx_module_test(export-compile-commands)
-endif ()
-
-macro (setup_export_build_database_targets)
-  set(RunCMake_CXXModules_TARGETS
-    cmake_build_database-CXX
-    cmake_build_database)
-
-  if (RunCMake_GENERATOR_IS_MULTI_CONFIG)
-    list(INSERT RunCMake_CXXModules_TARGETS 0
-      cmake_build_database-CXX-Debug
-      cmake_build_database-Debug
-      # Other config targets.
-      cmake_build_database-CXX-Release@Release
-      cmake_build_database-Release@Release)
-  endif ()
-endmacro ()
-
-# Tests which require build database support.
-if ("build_database" IN_LIST CMake_TEST_MODULE_COMPILATION)
-  setup_export_build_database_targets()
-  set(RunCMake_CXXModules_NO_TEST 1)
-
-  run_cxx_module_test(export-build-database)
-
-  unset(RunCMake_CXXModules_NO_TEST)
-  unset(RunCMake_CXXModules_TARGETS)
-endif ()
-
-# Tests which require collation work.
-if ("collation" IN_LIST CMake_TEST_MODULE_COMPILATION)
-  run_cxx_module_test(duplicate-sources)
-  run_cxx_module_test(public-req-private)
-  set(RunCMake_CXXModules_NO_TEST 1)
-  run_cxx_module_test(req-private-other-target)
-  unset(RunCMake_CXXModules_NO_TEST)
-  run_cxx_module_test_rebuild(depchain-modmap)
-  run_cxx_module_test_rebuild(depchain-modules-json-file)
-  if (RunCMake_GENERATOR MATCHES "Ninja")
-    run_cxx_module_test_rebuild(depchain-collation-restat)
-  endif ()
-endif ()
-
-# Tests which use named modules in shared libraries.
-if ("shared" IN_LIST CMake_TEST_MODULE_COMPILATION)
-  run_cxx_module_test(library library-shared -DBUILD_SHARED_LIBS=ON)
-endif ()
-
-# Tests which use partitions.
-if ("partitions" IN_LIST CMake_TEST_MODULE_COMPILATION)
-  run_cxx_module_test(partitions)
-endif ()
-
-# Tests which use internal partitions.
-if ("internal_partitions" IN_LIST CMake_TEST_MODULE_COMPILATION)
-  run_cxx_module_test(internal-partitions)
-endif ()
-
-function (run_cxx_module_import_test type name)
-  set(RunCMake_CXXModules_INSTALL 0)
-
-  if ("EXPORT_BUILD_DATABASE" IN_LIST ARGN)
-    list(REMOVE_ITEM ARGN EXPORT_BUILD_DATABASE)
-    list(APPEND ARGN -DCMAKE_EXPORT_BUILD_DATABASE=1)
-  endif ()
-
-  run_cxx_module_test(import-modules "import-modules-${name}" "-DCMAKE_PREFIX_PATH=${RunCMake_BINARY_DIR}/examples/${name}-${type}" ${ARGN})
-endfunction ()
-
-# Tests which install BMIs
-if ("export_bmi" IN_LIST CMake_TEST_MODULE_COMPILATION)
-  run_cxx_module_test(export-interface-no-properties-build)
-  run_cxx_module_test(export-interface-build)
-  run_cxx_module_test(export-include-directories-build)
-  run_cxx_module_test(export-include-directories-old-cmake-build)
-  run_cxx_module_test(export-usage-build)
-  run_cxx_module_test(export-bmi-and-interface-build)
-  run_cxx_module_test(export-command-sepdir-build)
-  run_cxx_module_test(export-transitive-targets-build)
-  run_cxx_module_test(export-transitive-modules1-build)
-  run_cxx_module_test(export-transitive-modules-build export-transitive-modules-build "-DCMAKE_PREFIX_PATH=${RunCMake_BINARY_DIR}/examples/export-transitive-modules1-build-build" )
-  run_cxx_module_test(export-with-headers-build)
-
-  if ("collation" IN_LIST CMake_TEST_MODULE_COMPILATION AND
-      "bmionly" IN_LIST CMake_TEST_MODULE_COMPILATION)
-    run_cxx_module_import_test(build export-interface-build)
-    run_cxx_module_import_test(build export-interface-no-properties-build -DNO_PROPERTIES=1)
-    run_cxx_module_import_test(build export-include-directories-build -DINCLUDE_PROPERTIES=1)
-    run_cxx_module_import_test(build export-bmi-and-interface-build -DWITH_BMIS=1)
-    run_cxx_module_import_test(build export-command-sepdir-build -DEXPORT_COMMAND_SEPDIR=1)
-    run_cxx_module_import_test(build export-transitive-targets-build -DTRANSITIVE_TARGETS=1)
-    run_cxx_module_import_test(build export-transitive-modules-build -DTRANSITIVE_MODULES=1)
-    run_cxx_module_import_test(build export-with-headers-build -DWITH_HEADERS=1)
-
-    if ("build_database" IN_LIST CMake_TEST_MODULE_COMPILATION)
-      setup_export_build_database_targets()
-
-      run_cxx_module_import_test(build export-build-database -DBUILD_DATABASE=1 EXPORT_BUILD_DATABASE)
-
-      unset(RunCMake_CXXModules_TARGETS)
-    endif ()
-  endif ()
-endif ()
-
-# All of the following tests perform installation.
-set(RunCMake_CXXModules_INSTALL 1)
-
-# Tests which install BMIs
-if ("install_bmi" IN_LIST CMake_TEST_MODULE_COMPILATION)
-  run_cxx_module_test(install-bmi)
-  run_cxx_module_test(install-bmi-and-interfaces)
-
-  if ("export_bmi" IN_LIST CMake_TEST_MODULE_COMPILATION)
-    run_cxx_module_test(export-interface-no-properties-install)
-    run_cxx_module_test(export-interface-install)
-    run_cxx_module_test(export-include-directories-install)
-    run_cxx_module_test(export-include-directories-old-cmake-install)
-    run_cxx_module_test(export-usage-install)
-    run_cxx_module_test(export-bmi-and-interface-install)
-    run_cxx_module_test(export-command-sepdir-install)
-    run_cxx_module_test(export-transitive-targets-install)
-    run_cxx_module_test(export-transitive-modules1-install)
-    run_cxx_module_test(export-transitive-modules-install export-transitive-modules-install "-DCMAKE_PREFIX_PATH=${RunCMake_BINARY_DIR}/examples/export-transitive-modules1-install-install" )
-    run_cxx_module_test(export-with-headers-install)
-
-    if ("collation" IN_LIST CMake_TEST_MODULE_COMPILATION AND
-        "bmionly" IN_LIST CMake_TEST_MODULE_COMPILATION)
-      run_cxx_module_import_test(install export-interface-install)
-      run_cxx_module_import_test(install export-interface-no-properties-install -DNO_PROPERTIES=1)
-      run_cxx_module_import_test(install export-include-directories-install -DINCLUDE_PROPERTIES=1)
-      run_cxx_module_import_test(install export-bmi-and-interface-install -DWITH_BMIS=1)
-      run_cxx_module_import_test(install export-command-sepdir-install -DEXPORT_COMMAND_SEPDIR=1)
-      run_cxx_module_import_test(install export-transitive-targets-install -DTRANSITIVE_TARGETS=1)
-      run_cxx_module_import_test(install export-transitive-modules-install -DTRANSITIVE_MODULES=1)
-      run_cxx_module_import_test(install export-with-headers-install -DWITH_HEADERS=1)
-    endif ()
-  endif ()
-endif ()
-
-# All remaining tests require a working `Ninja` generator to set up a test case
-# for the current generator.
-if (NOT "ninja" IN_LIST CMake_TEST_MODULE_COMPILATION)
-  return ()
-endif ()
-# All remaining tests require `bmionly` in order to consume from the `ninja`
-# build.
-if (NOT "bmionly" IN_LIST CMake_TEST_MODULE_COMPILATION)
-  return ()
-endif ()
-
-function (run_cxx_module_test_ninja directory)
-  set(RunCMake_GENERATOR "Ninja")
-  set(RunCMake_CXXModules_NO_TEST 1)
-  set(RunCMake_CXXModules_INSTALL 1)
-  # `Ninja` is not a multi-config generator.
-  set(RunCMake_GENERATOR_IS_MULTI_CONFIG 0)
-  run_cxx_module_test("${directory}" "${directory}-ninja" ${ARGN})
-endfunction ()
-
-# Installation happens within `run_cxx_module_test_ninja`.
-set(RunCMake_CXXModules_INSTALL 0)
-
-set(test_set modules-from-ninja)
-run_cxx_module_test_ninja("export-${test_set}")
-run_cxx_module_test(import-modules "import-${test_set}" "-DCMAKE_PREFIX_PATH=${RunCMake_BINARY_DIR}/examples/export-${test_set}-ninja-install" -DFROM_NINJA=1)

Tests/RunCMake/CXXModules/examples/public-req-private-build-stdout.txt

@@ -1 +0,0 @@
-CMake Error: Public C\+\+ module source `.*/Tests/RunCMake/CXXModules/examples/public-req-private/pub\.cxx` requires the `priv` C\+\+ module which is provided by a private source

Tests/RunCMake/CXXModulesCompile/CMakeLists.txt

@@ -0,0 +1,4 @@
+cmake_minimum_required(VERSION 3.23)
+project(${RunCMake_TEST} NONE)
+
+include(${RunCMake_TEST}.cmake)

Tests/RunCMake/CXXModulesCompile/Inspect.cmake

@@ -0,0 +1,23 @@
+enable_language(CXX)
+
+set(info "")
+
+# See `Modules/Compiler/MSVC-CXX.cmake` for this. If there is explicitly no
+# default, the feature list is populated to be everything.
+if (DEFINED CMAKE_CXX_STANDARD_DEFAULT AND
+    CMAKE_CXX_STANDARD_DEFAULT STREQUAL "")
+  set(CMAKE_CXX_COMPILE_FEATURES "")
+endif ()
+
+# Forward information about the C++ compile features.
+string(APPEND info "\
+set(CMAKE_CXX_COMPILE_FEATURES \"${CMAKE_CXX_COMPILE_FEATURES}\")
+set(CMAKE_MAKE_PROGRAM \"${CMAKE_MAKE_PROGRAM}\")
+set(CMAKE_CXX_COMPILER_VERSION \"${CMAKE_CXX_COMPILER_VERSION}\")
+set(CMAKE_CXX_OUTPUT_EXTENSION \"${CMAKE_CXX_OUTPUT_EXTENSION}\")
+set(CMAKE_CXX20_STANDARD_COMPILE_OPTION \"${CMAKE_CXX20_STANDARD_COMPILE_OPTION}\")
+set(CMAKE_CXX_COMPILER_FRONTEND_VARIANT \"${CMAKE_CXX_COMPILER_FRONTEND_VARIANT}\")
+set(CMAKE_CXX_MODULE_MAP_FORMAT \"${CMAKE_CXX_MODULE_MAP_FORMAT}\")
+")
+
+file(WRITE "${CMAKE_CURRENT_BINARY_DIR}/info.cmake" "${info}")

Tests/RunCMake/CXXModulesCompile/RunCMakeTest.cmake

@@ -0,0 +1,372 @@
+include(RunCMake)
+
+set(stdlib_custom_json)
+if (CMake_TEST_CXX_STDLIB_MODULES_JSON)
+  list(APPEND stdlib_custom_json
+    -DCMAKE_CXX_STDLIB_MODULES_JSON=${CMake_TEST_CXX_STDLIB_MODULES_JSON})
+endif ()
+
+run_cmake(Inspect ${stdlib_custom_json})
+include("${RunCMake_BINARY_DIR}/Inspect-build/info.cmake")
+
+if (RunCMake_GENERATOR MATCHES "Ninja")
+  execute_process(
+    COMMAND "${CMAKE_MAKE_PROGRAM}" --version
+    RESULT_VARIABLE res
+    OUTPUT_VARIABLE ninja_version
+    ERROR_VARIABLE err
+    OUTPUT_STRIP_TRAILING_WHITESPACE
+    ERROR_STRIP_TRAILING_WHITESPACE)
+
+  if (res)
+    message(WARNING
+      "Failed to determine `ninja` version: ${err}")
+    set(ninja_version "0")
+  endif ()
+endif ()
+
+set(generator_supports_cxx_modules 0)
+if (RunCMake_GENERATOR MATCHES "Ninja" AND
+    ninja_version VERSION_GREATER_EQUAL "1.11" AND
+    "cxx_std_20" IN_LIST CMAKE_CXX_COMPILE_FEATURES)
+  set(generator_supports_cxx_modules 1)
+endif ()
+
+if (RunCMake_GENERATOR MATCHES "Visual Studio" AND
+    CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL "19.34")
+  set(generator_supports_cxx_modules 1)
+endif ()
+
+# Test behavior when the generator does not support C++20 modules.
+if (NOT generator_supports_cxx_modules)
+  # Bail; the remaining tests require the generator to successfully generate
+  # with C++20 modules in the source list.
+  return ()
+endif ()
+
+# This performs actual compilation tests; avoid it when not requested.
+if (NOT CMake_TEST_MODULE_COMPILATION)
+  return ()
+endif ()
+
+# Module compilation features:
+# Compiler-based:
+# - `named`: basic support for named modules is available
+# - `shared`: shared libraries are supported
+# - `partitions`: module partitions are supported
+# - `internal_partitions`: internal module partitions are supported
+# - `bmionly`: the compiler supports BMI-only builds
+# - `import_std23`: the compiler supports `import std` for C++23
+#
+# Generator-based:
+# - `compile_commands`: the generator supports `compile_commands.json`
+# - `collation`: the generator supports module collation features
+# - `export_bmi`: the generator supports exporting BMIs
+# - `ninja`: a `ninja` binary is available to perform `Ninja`-only testing
+#   (assumed if the generator matches `Ninja`).
+string(REPLACE "," ";" CMake_TEST_MODULE_COMPILATION "${CMake_TEST_MODULE_COMPILATION}")
+if (RunCMake_GENERATOR MATCHES "Ninja")
+  list(APPEND CMake_TEST_MODULE_COMPILATION
+    "ninja")
+endif ()
+
+function (run_cxx_module_test directory)
+  set(test_name "${directory}")
+  if (NOT ARGN STREQUAL "")
+    list(POP_FRONT ARGN test_name)
+  endif ()
+
+  set(RunCMake_TEST_SOURCE_DIR "${CMAKE_CURRENT_LIST_DIR}/examples/${directory}")
+  set(RunCMake_TEST_BINARY_DIR "${RunCMake_BINARY_DIR}/examples/${test_name}-build")
+
+  if (RunCMake_GENERATOR_IS_MULTI_CONFIG)
+    set(RunCMake_TEST_OPTIONS -DCMAKE_CONFIGURATION_TYPES=Debug)
+  else ()
+    set(RunCMake_TEST_OPTIONS -DCMAKE_BUILD_TYPE=Debug)
+  endif ()
+  if (directory MATCHES "import-std")
+    list(APPEND RunCMake_TEST_OPTIONS
+      ${stdlib_custom_json})
+  endif ()
+
+  if (RunCMake_CXXModules_INSTALL)
+    set(prefix "${RunCMake_BINARY_DIR}/examples/${test_name}-install")
+    file(REMOVE_RECURSE "${prefix}")
+    list(APPEND RunCMake_TEST_OPTIONS
+      "-DCMAKE_INSTALL_PREFIX=${prefix}")
+  endif ()
+
+  list(APPEND RunCMake_TEST_OPTIONS
+    "-DCMake_TEST_MODULE_COMPILATION_RULES=${CMake_TEST_MODULE_COMPILATION_RULES}"
+    ${ARGN})
+  run_cmake("examples/${test_name}")
+  set(RunCMake_TEST_NO_CLEAN 1)
+  if (RunCMake_CXXModules_TARGET)
+    run_cmake_command("examples/${test_name}-build" "${CMAKE_COMMAND}" --build . --config Debug --target "${RunCMake_CXXModules_TARGET}")
+  else ()
+    run_cmake_command("examples/${test_name}-build" "${CMAKE_COMMAND}" --build . --config Debug)
+    foreach (RunCMake_CXXModules_TARGET IN LISTS RunCMake_CXXModules_TARGETS)
+      set(RunCMake_CXXModules_CONFIG "Debug")
+      set(RunCMake_CXXModules_NAME_SUFFIX "")
+      if (RunCMake_CXXModules_TARGET MATCHES "(.*)@(.*)")
+        set(RunCMake_CXXModules_TARGET "${CMAKE_MATCH_1}")
+        set(RunCMake_CXXModules_CONFIG "${CMAKE_MATCH_2}")
+        set(RunCMake_CXXModules_NAME_SUFFIX "-${RunCMake_CXXModules_CONFIG}")
+      endif ()
+      run_cmake_command("examples/${test_name}-target-${RunCMake_CXXModules_TARGET}${RunCMake_CXXModules_NAME_SUFFIX}" "${CMAKE_COMMAND}" --build . --target "${RunCMake_CXXModules_TARGET}" --config "${RunCMake_CXXModules_CONFIG}")
+    endforeach ()
+  endif ()
+  if (RunCMake_CXXModules_INSTALL)
+    run_cmake_command("examples/${test_name}-install" "${CMAKE_COMMAND}" --build . --target install --config Debug)
+  endif ()
+  if (NOT RunCMake_CXXModules_NO_TEST)
+    run_cmake_command("examples/${test_name}-test" "${CMAKE_CTEST_COMMAND}" -C Debug --output-on-failure)
+  endif ()
+  if (RunCMake_CXXModules_REBUILD)
+    execute_process(COMMAND ${CMAKE_COMMAND} -E sleep 1.125) # handle 1s resolution
+    include("${RunCMake_TEST_SOURCE_DIR}/pre-rebuild.cmake")
+    execute_process(COMMAND ${CMAKE_COMMAND} -E sleep 1.125) # handle 1s resolution
+    run_cmake_command("examples/${test_name}-rebuild" "${CMAKE_COMMAND}" --build . --config Debug)
+  endif ()
+endfunction ()
+
+function (run_cxx_module_test_target directory target)
+  set(RunCMake_CXXModules_TARGET "${target}")
+  set(RunCMake_CXXModules_NO_TEST 1)
+  run_cxx_module_test("${directory}" ${ARGN})
+endfunction ()
+
+function (run_cxx_module_test_rebuild directory)
+  set(RunCMake_CXXModules_INSTALL 0)
+  set(RunCMake_CXXModules_NO_TEST 1)
+  set(RunCMake_CXXModules_REBUILD 1)
+  run_cxx_module_test("${directory}" ${ARGN})
+endfunction ()
+
+if (RunCMake_GENERATOR MATCHES "Ninja")
+  if (RunCMake_GENERATOR_IS_MULTI_CONFIG)
+    set(ninja_cmp0154_target "CMakeFiles/ninja_cmp0154.dir/Debug/unrelated.cxx${CMAKE_CXX_OUTPUT_EXTENSION}")
+  else ()
+    set(ninja_cmp0154_target "CMakeFiles/ninja_cmp0154.dir/unrelated.cxx${CMAKE_CXX_OUTPUT_EXTENSION}")
+  endif ()
+  run_cxx_module_test_target(ninja-cmp0154 "${ninja_cmp0154_target}")
+endif ()
+
+run_cxx_module_test(scan-with-pch)
+
+# Tests which use named modules.
+if ("named" IN_LIST CMake_TEST_MODULE_COMPILATION)
+  run_cxx_module_test(simple)
+  run_cxx_module_test(file-sets-with-dot)
+  run_cxx_module_test(vs-without-flags)
+  run_cxx_module_test(library library-static -DBUILD_SHARED_LIBS=OFF)
+  run_cxx_module_test(unity-build)
+  run_cxx_module_test(object-library)
+  run_cxx_module_test(generated)
+  run_cxx_module_test(deep-chain)
+  run_cxx_module_test(non-trivial-collation-order)
+  run_cxx_module_test(non-trivial-collation-order-randomized)
+  run_cxx_module_test(duplicate)
+  set(RunCMake_CXXModules_NO_TEST 1)
+  run_cxx_module_test(import-from-object)
+  run_cxx_module_test(circular)
+  run_cxx_module_test(try-compile)
+  run_cxx_module_test(try-run)
+  unset(RunCMake_CXXModules_NO_TEST)
+  run_cxx_module_test(same-src-name)
+  run_cxx_module_test(scan_properties)
+  run_cxx_module_test(target-objects)
+
+  if ("cxx_std_23" IN_LIST CMAKE_CXX_COMPILE_FEATURES AND
+      "import_std23" IN_LIST CMake_TEST_MODULE_COMPILATION)
+    run_cxx_module_test(import-std)
+    set(RunCMake_CXXModules_NO_TEST 1)
+    run_cxx_module_test(import-std-no-std-property)
+    unset(RunCMake_CXXModules_NO_TEST)
+    run_cxx_module_test(import-std-export-no-std-build)
+    set(RunCMake_CXXModules_INSTALL 1)
+    run_cxx_module_test(import-std-export-no-std-install)
+    unset(RunCMake_CXXModules_INSTALL)
+
+    if ("collation" IN_LIST CMake_TEST_MODULE_COMPILATION)
+      run_cxx_module_test(import-std-not-in-export-build)
+      run_cxx_module_test(import-std-transitive import-std-transitive-not-in-export-build "-DCMAKE_PREFIX_PATH=${RunCMake_BINARY_DIR}/examples/import-std-not-in-export-build-build")
+
+      set(RunCMake_CXXModules_INSTALL 1)
+      run_cxx_module_test(import-std-not-in-export-install)
+      unset(RunCMake_CXXModules_INSTALL)
+      run_cxx_module_test(import-std-transitive import-std-transitive-not-in-export-install "-DCMAKE_PREFIX_PATH=${RunCMake_BINARY_DIR}/examples/import-std-not-in-export-install-install")
+
+      run_cxx_module_test(import-std-transitive import-std-transitive-export-no-std-build "-DCMAKE_PREFIX_PATH=${RunCMake_BINARY_DIR}/examples/import-std-export-no-std-build-build" -DEXPORT_NO_STD=1)
+      run_cxx_module_test(import-std-transitive import-std-transitive-export-no-std-install "-DCMAKE_PREFIX_PATH=${RunCMake_BINARY_DIR}/examples/import-std-export-no-std-install-install" -DEXPORT_NO_STD=1)
+    endif ()
+  endif ()
+endif ()
+
+# Tests which require compile commands support.
+if ("compile_commands" IN_LIST CMake_TEST_MODULE_COMPILATION)
+  run_cxx_module_test(export-compile-commands)
+endif ()
+
+macro (setup_export_build_database_targets)
+  set(RunCMake_CXXModules_TARGETS
+    cmake_build_database-CXX
+    cmake_build_database)
+
+  if (RunCMake_GENERATOR_IS_MULTI_CONFIG)
+    list(INSERT RunCMake_CXXModules_TARGETS 0
+      cmake_build_database-CXX-Debug
+      cmake_build_database-Debug
+      # Other config targets.
+      cmake_build_database-CXX-Release@Release
+      cmake_build_database-Release@Release)
+  endif ()
+endmacro ()
+
+# Tests which require build database support.
+if ("build_database" IN_LIST CMake_TEST_MODULE_COMPILATION)
+  setup_export_build_database_targets()
+  set(RunCMake_CXXModules_NO_TEST 1)
+
+  run_cxx_module_test(export-build-database)
+
+  unset(RunCMake_CXXModules_NO_TEST)
+  unset(RunCMake_CXXModules_TARGETS)
+endif ()
+
+# Tests which require collation work.
+if ("collation" IN_LIST CMake_TEST_MODULE_COMPILATION)
+  run_cxx_module_test(duplicate-sources)
+  run_cxx_module_test(public-req-private)
+  set(RunCMake_CXXModules_NO_TEST 1)
+  run_cxx_module_test(req-private-other-target)
+  unset(RunCMake_CXXModules_NO_TEST)
+  run_cxx_module_test_rebuild(depchain-modmap)
+  run_cxx_module_test_rebuild(depchain-modules-json-file)
+  if (RunCMake_GENERATOR MATCHES "Ninja")
+    run_cxx_module_test_rebuild(depchain-collation-restat)
+  endif ()
+endif ()
+
+# Tests which use named modules in shared libraries.
+if ("shared" IN_LIST CMake_TEST_MODULE_COMPILATION)
+  run_cxx_module_test(library library-shared -DBUILD_SHARED_LIBS=ON)
+endif ()
+
+# Tests which use partitions.
+if ("partitions" IN_LIST CMake_TEST_MODULE_COMPILATION)
+  run_cxx_module_test(partitions)
+endif ()
+
+# Tests which use internal partitions.
+if ("internal_partitions" IN_LIST CMake_TEST_MODULE_COMPILATION)
+  run_cxx_module_test(internal-partitions)
+endif ()
+
+function (run_cxx_module_import_test type name)
+  set(RunCMake_CXXModules_INSTALL 0)
+
+  if ("EXPORT_BUILD_DATABASE" IN_LIST ARGN)
+    list(REMOVE_ITEM ARGN EXPORT_BUILD_DATABASE)
+    list(APPEND ARGN -DCMAKE_EXPORT_BUILD_DATABASE=1)
+  endif ()
+
+  run_cxx_module_test(import-modules "import-modules-${name}" "-DCMAKE_PREFIX_PATH=${RunCMake_BINARY_DIR}/examples/${name}-${type}" ${ARGN})
+endfunction ()
+
+# Tests which install BMIs
+if ("export_bmi" IN_LIST CMake_TEST_MODULE_COMPILATION)
+  run_cxx_module_test(export-interface-no-properties-build)
+  run_cxx_module_test(export-interface-build)
+  run_cxx_module_test(export-include-directories-build)
+  run_cxx_module_test(export-include-directories-old-cmake-build)
+  run_cxx_module_test(export-usage-build)
+  run_cxx_module_test(export-bmi-and-interface-build)
+  run_cxx_module_test(export-command-sepdir-build)
+  run_cxx_module_test(export-transitive-targets-build)
+  run_cxx_module_test(export-transitive-modules1-build)
+  run_cxx_module_test(export-transitive-modules-build export-transitive-modules-build "-DCMAKE_PREFIX_PATH=${RunCMake_BINARY_DIR}/examples/export-transitive-modules1-build-build" )
+  run_cxx_module_test(export-with-headers-build)
+
+  if ("collation" IN_LIST CMake_TEST_MODULE_COMPILATION AND
+      "bmionly" IN_LIST CMake_TEST_MODULE_COMPILATION)
+    run_cxx_module_import_test(build export-interface-build)
+    run_cxx_module_import_test(build export-interface-no-properties-build -DNO_PROPERTIES=1)
+    run_cxx_module_import_test(build export-include-directories-build -DINCLUDE_PROPERTIES=1)
+    run_cxx_module_import_test(build export-bmi-and-interface-build -DWITH_BMIS=1)
+    run_cxx_module_import_test(build export-command-sepdir-build -DEXPORT_COMMAND_SEPDIR=1)
+    run_cxx_module_import_test(build export-transitive-targets-build -DTRANSITIVE_TARGETS=1)
+    run_cxx_module_import_test(build export-transitive-modules-build -DTRANSITIVE_MODULES=1)
+    run_cxx_module_import_test(build export-with-headers-build -DWITH_HEADERS=1)
+
+    if ("build_database" IN_LIST CMake_TEST_MODULE_COMPILATION)
+      setup_export_build_database_targets()
+
+      run_cxx_module_import_test(build export-build-database -DBUILD_DATABASE=1 EXPORT_BUILD_DATABASE)
+
+      unset(RunCMake_CXXModules_TARGETS)
+    endif ()
+  endif ()
+endif ()
+
+# All of the following tests perform installation.
+set(RunCMake_CXXModules_INSTALL 1)
+
+# Tests which install BMIs
+if ("install_bmi" IN_LIST CMake_TEST_MODULE_COMPILATION)
+  run_cxx_module_test(install-bmi)
+  run_cxx_module_test(install-bmi-and-interfaces)
+
+  if ("export_bmi" IN_LIST CMake_TEST_MODULE_COMPILATION)
+    run_cxx_module_test(export-interface-no-properties-install)
+    run_cxx_module_test(export-interface-install)
+    run_cxx_module_test(export-include-directories-install)
+    run_cxx_module_test(export-include-directories-old-cmake-install)
+    run_cxx_module_test(export-usage-install)
+    run_cxx_module_test(export-bmi-and-interface-install)
+    run_cxx_module_test(export-command-sepdir-install)
+    run_cxx_module_test(export-transitive-targets-install)
+    run_cxx_module_test(export-transitive-modules1-install)
+    run_cxx_module_test(export-transitive-modules-install export-transitive-modules-install "-DCMAKE_PREFIX_PATH=${RunCMake_BINARY_DIR}/examples/export-transitive-modules1-install-install" )
+    run_cxx_module_test(export-with-headers-install)
+
+    if ("collation" IN_LIST CMake_TEST_MODULE_COMPILATION AND
+        "bmionly" IN_LIST CMake_TEST_MODULE_COMPILATION)
+      run_cxx_module_import_test(install export-interface-install)
+      run_cxx_module_import_test(install export-interface-no-properties-install -DNO_PROPERTIES=1)
+      run_cxx_module_import_test(install export-include-directories-install -DINCLUDE_PROPERTIES=1)
+      run_cxx_module_import_test(install export-bmi-and-interface-install -DWITH_BMIS=1)
+      run_cxx_module_import_test(install export-command-sepdir-install -DEXPORT_COMMAND_SEPDIR=1)
+      run_cxx_module_import_test(install export-transitive-targets-install -DTRANSITIVE_TARGETS=1)
+      run_cxx_module_import_test(install export-transitive-modules-install -DTRANSITIVE_MODULES=1)
+      run_cxx_module_import_test(install export-with-headers-install -DWITH_HEADERS=1)
+    endif ()
+  endif ()
+endif ()
+
+# All remaining tests require a working `Ninja` generator to set up a test case
+# for the current generator.
+if (NOT "ninja" IN_LIST CMake_TEST_MODULE_COMPILATION)
+  return ()
+endif ()
+# All remaining tests require `bmionly` in order to consume from the `ninja`
+# build.
+if (NOT "bmionly" IN_LIST CMake_TEST_MODULE_COMPILATION)
+  return ()
+endif ()
+
+function (run_cxx_module_test_ninja directory)
+  set(RunCMake_GENERATOR "Ninja")
+  set(RunCMake_CXXModules_NO_TEST 1)
+  set(RunCMake_CXXModules_INSTALL 1)
+  # `Ninja` is not a multi-config generator.
+  set(RunCMake_GENERATOR_IS_MULTI_CONFIG 0)
+  run_cxx_module_test("${directory}" "${directory}-ninja" ${ARGN})
+endfunction ()
+
+# Installation happens within `run_cxx_module_test_ninja`.
+set(RunCMake_CXXModules_INSTALL 0)
+
+set(test_set modules-from-ninja)
+run_cxx_module_test_ninja("export-${test_set}")
+run_cxx_module_test(import-modules "import-${test_set}" "-DCMAKE_PREFIX_PATH=${RunCMake_BINARY_DIR}/examples/export-${test_set}-ninja-install" -DFROM_NINJA=1)

Tests/RunCMake/CXXModulesCompile/check-json.cmake

@@ -0,0 +1,227 @@
+function (json_placeholders in out)
+  string(REPLACE "<CONFIG>" "${CXXModules_config}" in "${in}")
+  string(TOLOWER "${CXXModules_config}" config_lower)
+  string(REPLACE "<CONFIG_LOWER>" "${config_lower}" in "${in}")
+  string(REPLACE "<CONFIG_OTHER>" "${CXXModules_config_other}" in "${in}")
+  string(TOLOWER "${CXXModules_config_other}" config_lower)
+  string(REPLACE "<CONFIG_OTHER_LOWER>" "${config_lower}" in "${in}")
+  if (RunCMake_GENERATOR_IS_MULTI_CONFIG)
+    string(REPLACE "<CONFIG_DIR>" "/${CXXModules_config}" in "${in}")
+    string(REPLACE "<CONFIG_OTHER_DIR>" "/${CXXModules_config_other}" in "${in}")
+  else ()
+    string(REPLACE "<CONFIG_DIR>" "" in "${in}")
+    string(REPLACE "<CONFIG_OTHER_DIR>" "" in "${in}")
+  endif ()
+  if (CMAKE_BUILD_TYPE)
+    string(REPLACE "<CONFIG_FORCE>" "${CXXModules_config}" in "${in}")
+    string(REPLACE "<CONFIG_OTHER_FORCE>" "${CXXModules_config_other}" in "${in}")
+  else ()
+    string(REPLACE "<CONFIG_FORCE>" "noconfig" in "${in}")
+  endif ()
+  string(REPLACE "<SOURCE_DIR>" "${RunCMake_SOURCE_DIR}" in "${in}")
+  string(REPLACE "<BINARY_DIR>" "${RunCMake_TEST_BINARY_DIR}" in "${in}")
+  string(REPLACE "<OBJEXT>" "${CMAKE_CXX_OUTPUT_EXTENSION}" in "${in}")
+  if (CMAKE_CXX_MODULE_MAP_FORMAT STREQUAL "gcc")
+    set(bmiflag "-fmodule-only")
+    set(bmiext "gcm")
+  elseif (CMAKE_CXX_MODULE_MAP_FORMAT STREQUAL "clang")
+    set(bmiflag "--precompile")
+    set(bmiext "pcm")
+  elseif (CMAKE_CXX_MODULE_MAP_FORMAT STREQUAL "msvc")
+    set(bmiflag "-ifcOutput.*")
+    set(bmiext "ifc")
+  endif ()
+  string(REPLACE "<BMI_ONLY_FLAG>" "${bmiflag}" in "${in}")
+  string(REPLACE "<BMIEXT>" ".${bmiext}" in "${in}")
+  set(output_flag "-o")
+  if (CMAKE_CXX_COMPILER_FRONTEND_VARIANT STREQUAL "MSVC")
+    set(output_flag "-Fo")
+  endif ()
+  string(REPLACE "<OUTPUT_FLAG>" "${output_flag}" in "${in}")
+  string(REPLACE "<CXX20_OPTION>" "${CMAKE_CXX20_STANDARD_COMPILE_OPTION}" in "${in}")
+  string(REPLACE "<HEX>" "[0-9a-f]+" in "${in}")
+  string(REPLACE "REGEX:" "" in "${in}")
+  string(REPLACE "PATH:" "" in "${in}")
+  set("${out}" "${in}" PARENT_SCOPE)
+endfunction ()
+
+function (check_json_value path actual_type expect_type actual_value expect_value)
+  if (NOT actual_type STREQUAL expect_type)
+    string(APPEND RunCMake_TEST_FAILED
+      "Type mismatch at:\n ${path}\nexpected:\n ${expect_type}\nactual:\n ${actual_type}\n")
+    set(RunCMake_TEST_FAILED "${RunCMake_TEST_FAILED}" PARENT_SCOPE)
+    return ()
+  endif ()
+
+  if (actual_type STREQUAL NULL)
+    # Nothing to check
+  elseif (actual_type STREQUAL BOOLEAN)
+    if (NOT actual_value STREQUAL expect_value)
+      string(APPEND RunCMake_TEST_FAILED
+        "Boolean mismatch at:\n ${path}\nexpected:\n ${expect_value}\nactual:\n ${actual_value}\n")
+    endif ()
+  elseif (actual_type STREQUAL NUMBER)
+    if (NOT actual_value EQUAL expect_value)
+      string(APPEND RunCMake_TEST_FAILED
+        "Number mismatch at:\n ${path}\nexpected:\n ${expect_value}\nactual:\n ${actual_value}\n")
+    endif ()
+  elseif (actual_type STREQUAL STRING)
+    # Allow some values to be ignored.
+    if (expect_value STREQUAL "<IGNORE>")
+      return ()
+    endif ()
+
+    json_placeholders("${expect_value}" expect_value_expanded)
+    if (expect_value MATCHES "^REGEX:PATH:")
+      string(REPLACE "\\" "/" actual_value_check "${actual_value}")
+      string(REGEX REPLACE "^\"(.*)\"$" "\\1" actual_value_check "${actual_value_check}")
+      if (NOT actual_value_check MATCHES "^${expect_value_expanded}$")
+        string(APPEND RunCMake_TEST_FAILED
+          "String mismatch (path regex) at:\n ${path}\nexpected:\n ^${expect_value_expanded}$\nactual:\n ${actual_value}\n")
+      endif ()
+    elseif (expect_value MATCHES "^REGEX:")
+      if (NOT actual_value MATCHES "^${expect_value_expanded}$")
+        string(APPEND RunCMake_TEST_FAILED
+          "String mismatch (regex) at:\n ${path}\nexpected:\n ^${expect_value_expanded}$\nactual:\n ${actual_value}\n")
+      endif ()
+    elseif (expect_value MATCHES "^PATH:")
+      string(REPLACE "\\" "/" actual_value_check "${actual_value}")
+      string(REGEX REPLACE "^\"(.*)\"$" "\\1" actual_value_check "${actual_value_check}")
+      if (NOT actual_value_check STREQUAL "${expect_value_expanded}")
+        string(APPEND RunCMake_TEST_FAILED
+          "String mismatch (path) at:\n ${path}\nexpected:\n ${expect_value_expanded}\nactual:\n ${actual_value}\n")
+      endif ()
+    elseif (NOT actual_value STREQUAL expect_value_expanded)
+      string(APPEND RunCMake_TEST_FAILED
+        "String mismatch at:\n ${path}\nexpected:\n ${expect_value_expanded}\nactual:\n ${actual_value}\n")
+    endif ()
+  elseif (actual_type STREQUAL ARRAY)
+    check_json_array("${path}" "${actual_value}" "${expect_value}")
+  elseif (actual_type STREQUAL OBJECT)
+    check_json_object("${path}" "${actual_value}" "${expect_value}")
+  endif ()
+
+  set(RunCMake_TEST_FAILED "${RunCMake_TEST_FAILED}" PARENT_SCOPE)
+endfunction ()
+
+# Check that two arrays are the same.
+function (check_json_array path actual expect)
+  if (item_filter)
+    string(JSON iter_len LENGTH "${actual}")
+    set(idx 0)
+    while (idx LESS iter_len)
+      string(JSON type TYPE "${actual}" "${idx}")
+      string(JSON item GET "${actual}" "${idx}")
+      if (type STREQUAL "STRING" AND
+          item MATCHES "${item_filter}")
+        string(JSON actual REMOVE "${actual}" "${idx}")
+        math(EXPR iter_len "${iter_len} - 1")
+      else ()
+        math(EXPR idx "${idx} + 1")
+      endif ()
+    endwhile ()
+  endif ()
+
+  string(JSON actual_len LENGTH "${actual}")
+  string(JSON expect_len LENGTH "${expect}")
+
+  set(iter_len "${actual_len}")
+  if (actual_len LESS expect_len)
+    string(APPEND RunCMake_TEST_FAILED
+      "Missing array items at:\n ${path}\n")
+  elseif (expect_len LESS actual_len)
+    string(APPEND RunCMake_TEST_FAILED
+      "Extra array items at:\n ${path}\n")
+    set(iter_len "${expect_len}")
+  endif ()
+
+  foreach (idx RANGE "${iter_len}")
+    if (idx EQUAL iter_len)
+      break ()
+    endif ()
+
+    set(new_path "${path}[${idx}]")
+    string(JSON actual_type TYPE "${actual}" "${idx}")
+    string(JSON expect_type TYPE "${expect}" "${idx}")
+    string(JSON actual_value GET "${actual}" "${idx}")
+    string(JSON expect_value GET "${expect}" "${idx}")
+    check_json_value("${new_path}" "${actual_type}" "${expect_type}" "${actual_value}" "${expect_value}")
+  endforeach ()
+
+  set(RunCMake_TEST_FAILED "${RunCMake_TEST_FAILED}" PARENT_SCOPE)
+endfunction ()
+
+# Check that two inner objects are the same.
+function (check_json_object path actual expect)
+  string(JSON actual_len LENGTH "${actual}")
+  string(JSON expect_len LENGTH "${expect}")
+
+  set(actual_keys "")
+  set(expect_keys "")
+  foreach (idx RANGE "${actual_len}")
+    if (idx EQUAL actual_len)
+      break ()
+    endif ()
+
+    string(JSON actual_key MEMBER "${actual}" "${idx}")
+    list(APPEND actual_keys "${actual_key}")
+  endforeach ()
+  foreach (idx RANGE "${expect_len}")
+    if (idx EQUAL expect_len)
+      break ()
+    endif ()
+
+    string(JSON expect_key MEMBER "${expect}" "${idx}")
+    list(APPEND expect_keys "${expect_key}")
+  endforeach ()
+
+  json_placeholders("${expect_keys}" expect_keys_expanded)
+
+  set(actual_keys_missed "${actual_keys}")
+  set(expect_keys_missed "${expect_keys}")
+
+  set(common_keys "")
+  set(expect_keys_stack "${expect_keys}")
+  while (expect_keys_stack)
+    list(POP_BACK expect_keys_stack expect_key)
+    json_placeholders("${expect_key}" expect_key_expanded)
+
+    if (expect_key_expanded IN_LIST actual_keys_missed AND
+        expect_key IN_LIST expect_keys_missed)
+      list(APPEND common_keys "${expect_key}")
+    endif ()
+
+    list(REMOVE_ITEM actual_keys_missed "${expect_key_expanded}")
+    list(REMOVE_ITEM expect_keys_missed "${expect_key}")
+  endwhile ()
+
+  if (actual_keys_missed)
+    string(REPLACE ";" ", " actual_keys_missed_text "${actual_keys_missed}")
+    string(APPEND RunCMake_TEST_FAILED
+      "Extra unexpected members at:\n ${path}\nactual:\n ${actual_keys_missed_text}\n")
+  endif ()
+  if (expect_keys_missed)
+    string(REPLACE ";" ", " expect_keys_missed_text "${expect_keys_missed}")
+    string(APPEND RunCMake_TEST_FAILED
+      "Missing expected members at\n ${path}\nactual:\n ${expect_keys_missed_text}\n")
+  endif ()
+
+  foreach (key IN LISTS common_keys)
+    json_placeholders("${key}" key_expanded)
+    set(new_path "${path}.${key_expanded}")
+    string(JSON actual_type TYPE "${actual}" "${key_expanded}")
+    string(JSON expect_type TYPE "${expect}" "${key}")
+    string(JSON actual_value GET "${actual}" "${key_expanded}")
+    string(JSON expect_value GET "${expect}" "${key}")
+    check_json_value("${new_path}" "${actual_type}" "${expect_type}" "${actual_value}" "${expect_value}")
+  endforeach ()
+
+  set(RunCMake_TEST_FAILED "${RunCMake_TEST_FAILED}" PARENT_SCOPE)
+endfunction ()
+
+# Check that two JSON objects are the same.
+function (check_json actual expect)
+  check_json_object("" "${actual}" "${expect}")
+
+  set(RunCMake_TEST_FAILED "${RunCMake_TEST_FAILED}" PARENT_SCOPE)
+endfunction ()

Tests/RunCMake/CXXModulesCompile/examples/duplicate-sources-stderr.txt

@@ -2,7 +2,7 @@ CMake Warning \(dev\) in CMakeLists\.txt:
   Target "duplicate_sources" has source file
 
     [^
-]*/Tests/RunCMake/CXXModules/examples/duplicate-sources/duplicate\.cxx
+]*/Tests/RunCMake/CXXModulesCompile/examples/duplicate-sources/duplicate\.cxx
 
   in a "FILE_SET TYPE CXX_MODULES" multiple times\.
 This warning is for project developers\.  Use -Wno-dev to suppress it\.