Adapt remaining HPX Modules to C++20 modules

.github/workflows/windows_debug_vs2026_modules.yml

@@ -0,0 +1,68 @@
+# Copyright (c) 2020 Mikael Simberg
+# Copyright (c) 2024-2026 The STE||AR Group
+#
+# SPDX-License-Identifier: BSL-1.0
+# Distributed under the Boost Software License, Version 1.0. (See accompanying
+# file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+name: Windows CI (Debug, VS2026 toolset, C++20 Modules)
+
+on: [pull_request]
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  build:
+    runs-on: windows-2025-vs2026
+
+    steps:
+    - uses: actions/checkout@v6
+    - uses: lukka/get-cmake@v4.3.2
+
+    - name: Install dependencies
+      run: |
+        md C:\projects
+        $client = new-object System.Net.WebClient
+        $client.DownloadFile("https://rostam.cct.lsu.edu/download/builder/vcpkg-export-hpx-dependencies-2026.7z","C:\projects\vcpkg-export-hpx-dependencies.7z")
+        7z x C:\projects\vcpkg-export-hpx-dependencies.7z -y -oC:\projects\vcpkg
+    - name: Configure
+      shell: bash
+      run: |
+          cmake . -Bbuild -G'Visual Studio 18 2026' \
+              -DCMAKE_BUILD_TYPE=Debug \
+              -DCMAKE_TOOLCHAIN_FILE='C:/projects/vcpkg/scripts/buildsystems/vcpkg.cmake' \
+              -DHPX_WITH_FETCH_ASIO=ON \
+              -DHPX_WITH_ASIO_TAG=asio-1-38-0 \
+              -DHPX_WITH_EXAMPLES=OFF \
+              -DHPX_WITH_TESTS=OFF \
+              -DHPX_WITH_TESTS_EXAMPLES=OFF \
+              -DHPX_WITH_DEPRECATION_WARNINGS=OFF \
+              -DHPX_WITH_TESTS_MAX_THREADS_PER_LOCALITY=2 \
+              -DHPX_COROUTINES_WITH_SWAP_CONTEXT_EMULATION=ON \
+              -DHPX_WITH_VERIFY_LOCKS=ON \
+              -DHPX_WITH_VERIFY_LOCKS_BACKTRACE=ON \
+              -DHPX_WITH_CHECK_MODULE_DEPENDENCIES=ON \
+              -DHPX_WITH_CXX_MODULES=ON \
+              -DHPX_WITH_DATAPAR=ON \
+              -DHPX_WITH_DATAPAR_BACKEND=EMULATE
+    - name: Build
+      shell: bash
+      run: |
+          cmake --build build --config Debug --target ALL_BUILD \
+            -- -maxcpucount:2 -verbosity:minimal -nologo
+    - name: Install
+      shell: bash
+      run: |
+          cmake --install build --config Debug
+#    - name: Test
+#      run: |
+#          $exclude_regex = & "$env:GITHUB_WORKSPACE/.github/ci-scripts/generate_ctest_exclude_regex.ps1" `
+#            "$env:GITHUB_WORKSPACE/.github/workflows/tests.examples.targets"
+#          cd build
+#          ctest `
+#          --output-on-failure `
+#            --build-config Debug `
+#            --tests-regex tests.examples `
+#            --exclude-regex $exclude_regex

CMakeLists.txt

@@ -293,17 +293,19 @@ if(HPX_WITH_DOCUMENTATION)
 endif()
 
 if(WIN32)
-  set(HPX_WITH_PSEUDO_DEPENDENCIES
-      OFF
-      CACHE INTERNAL "" FORCE
-  )
+  set(HPX_WITH_PSEUDO_DEPENDENCIES_DEFAULT OFF)
 else()
-  set(HPX_WITH_PSEUDO_DEPENDENCIES
-      ON
-      CACHE INTERNAL "" FORCE
-  )
+  set(HPX_WITH_PSEUDO_DEPENDENCIES_DEFAULT ON)
 endif()
 
+hpx_option(
+  HPX_WITH_PSEUDO_DEPENDENCIES
+  BOOL
+  "Turn compiler warnings into errors (default: ${HPX_WITH_PSEUDO_DEPENDENCIES_DEFAULT})"
+  ${HPX_WITH_PSEUDO_DEPENDENCIES_DEFAULT}
+  ADVANCED
+)
+
 hpx_option(
   HPX_WITH_UNITY_BUILD BOOL
   "Enable unity build for certain build targets (default OFF)" OFF ADVANCED

cmake/HPX_SetupAsio.cmake

@@ -46,8 +46,20 @@ elseif(NOT TARGET Asio::asio AND NOT HPX_FIND_PACKAGE)
   set(Asio_ROOT ${asio_SOURCE_DIR})
 
   add_library(asio INTERFACE)
+
+  # convert ASIO tag into CMake version
+  string(REGEX REPLACE "asio-([0-9]+)-([0-9]+)-([0-9]+)" "\\1.\\2.\\3" VERSION
+                       "${HPX_WITH_ASIO_TAG}"
+  )
+
+  # starting v1.37.0 ASIO has changed its directory structure
+  set(asio_base_directory ${Asio_ROOT}/asio/include)
+  if(VERSION VERSION_GREATER "1.36.0")
+    set(asio_base_directory ${Asio_ROOT}/include)
+  endif()
+
   target_include_directories(
-    asio SYSTEM INTERFACE $<BUILD_INTERFACE:${Asio_ROOT}/asio/include>
+    asio SYSTEM INTERFACE $<BUILD_INTERFACE:${asio_base_directory}>
                           $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>
   )
 
@@ -58,7 +70,7 @@ elseif(NOT TARGET Asio::asio AND NOT HPX_FIND_PACKAGE)
   )
 
   install(
-    DIRECTORY ${Asio_ROOT}/asio/include/
+    DIRECTORY ${asio_base_directory}/
     DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}
     COMPONENT core
     FILES_MATCHING

cmake/HPX_SetupTarget.cmake

@@ -264,23 +264,23 @@ function(hpx_setup_target target)
       target_compile_definitions(
         ${target} PRIVATE HPX_HAVE_FORCE_NO_CXX_MODULES
       )
-
-      # If modules are enabled, Clang emits DWARF v5, which requires using lld
-      # instead of ld.
-      if((NOT MSVC)
-         AND (CMAKE_CXX_COMPILER_ID MATCHES "Clang")
-         AND (NOT (CMAKE_CXX_COMPILER_ID MATCHES "AppleClang"))
-      )
-        get_target_property(_type ${target} TYPE)
-        if((_type STREQUAL "SHARED_LIBRARY") OR (_type STREQUAL "EXECUTABLE"))
-          target_link_options(${target} PRIVATE "-fuse-ld=lld")
-        endif()
-      endif()
     endif()
 
     set_target_properties(${target} PROPERTIES CXX_SCAN_FOR_MODULES OFF)
   endif()
 
+  # Newer Clang emits DWARF v5, which requires using lld instead of ld.
+  if(HPX_WITH_CXX_MODULES
+     AND (NOT MSVC)
+     AND (CMAKE_CXX_COMPILER_ID MATCHES "Clang")
+     AND (NOT (CMAKE_CXX_COMPILER_ID MATCHES "AppleClang"))
+  )
+    get_target_property(_type ${target} TYPE)
+    if((_type STREQUAL "SHARED_LIBRARY") OR (_type STREQUAL "EXECUTABLE"))
+      target_link_options(${target} PRIVATE "-fuse-ld=lld")
+    endif()
+  endif()
+
   get_target_property(target_EXCLUDE_FROM_ALL ${target} EXCLUDE_FROM_ALL)
 
   if(target_EXPORT AND NOT target_EXCLUDE_FROM_ALL)

components/component_storage/CMakeLists.txt

@@ -50,5 +50,15 @@ add_hpx_pseudo_dependencies(
   components.component_storage component_storage_component
 )
 
+# MSVC V1951 and V1952 exposes ICE compiling this in C++20 module mode
+if(HPX_WITH_CXX_MODULES
+   AND (CMAKE_CXX_COMPILER_ID STREQUAL "MSVC")
+   AND ((MSVC_VERSION EQUAL 1951) OR (MSVC_VERSION EQUAL 1952))
+)
+  target_compile_definitions(
+    component_storage_component PRIVATE HPX_HAVE_FORCE_NO_CXX_MODULES
+  )
+endif()
+
 add_subdirectory(tests)
 add_subdirectory(examples)

components/component_storage/include/hpx/components/component_storage/server/migrate_from_storage.hpp

@@ -11,8 +11,7 @@
 #include <hpx/modules/errors.hpp>
 #include <hpx/modules/functional.hpp>
 #include <hpx/modules/naming_base.hpp>
-#include <hpx/runtime_distributed/runtime_support.hpp>
-#include <hpx/runtime_distributed/server/migrate_component.hpp>
+#include <hpx/modules/runtime_distributed.hpp>
 
 #include <hpx/components/component_storage/export_definitions.hpp>
 #include <hpx/components/component_storage/server/component_storage.hpp>

components/component_storage/src/server/component_storage_server.cpp

@@ -5,9 +5,10 @@
 //  file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
 
 #include <hpx/config.hpp>
-#include <hpx/components/component_storage/server/component_storage.hpp>
 #include <hpx/modules/errors.hpp>
-#include <hpx/runtime_distributed/find_localities.hpp>
+#include <hpx/modules/runtime_distributed.hpp>
+
+#include <hpx/components/component_storage/server/component_storage.hpp>
 
 #include <vector>
 

components/containers/partitioned_vector/CMakeLists.txt

@@ -63,5 +63,15 @@ add_hpx_pseudo_dependencies(
   components.containers.partitioned_vector partitioned_vector_component
 )
 
+# MSVC V1951 and V1952 exposes ICE compiling this in C++20 module mode
+if(HPX_WITH_CXX_MODULES
+   AND (CMAKE_CXX_COMPILER_ID STREQUAL "MSVC")
+   AND ((MSVC_VERSION EQUAL 1951) OR (MSVC_VERSION EQUAL 1952))
+)
+  target_compile_definitions(
+    partitioned_vector_component PRIVATE HPX_HAVE_FORCE_NO_CXX_MODULES
+  )
+endif()
+
 add_subdirectory(tests)
 add_subdirectory(examples)

components/containers/partitioned_vector/include/hpx/components/containers/coarray/coarray.hpp

@@ -10,10 +10,11 @@
 #pragma once
 
 #include <hpx/collectives/spmd_block.hpp>
+#include <hpx/modules/runtime_distributed.hpp>
+#include <hpx/modules/type_support.hpp>
+
 #include <hpx/components/containers/partitioned_vector/partitioned_vector.hpp>
 #include <hpx/components/containers/partitioned_vector/partitioned_vector_view.hpp>
-#include <hpx/modules/type_support.hpp>
-#include <hpx/runtime_distributed/find_all_localities.hpp>
 
 #include <algorithm>
 #include <array>

components/containers/partitioned_vector/include/hpx/components/containers/partitioned_vector/partitioned_vector_decl.hpp

@@ -18,8 +18,8 @@
 #include <hpx/modules/distribution_policies.hpp>
 #include <hpx/modules/functional.hpp>
 #include <hpx/modules/runtime_components.hpp>
+#include <hpx/modules/runtime_distributed.hpp>
 #include <hpx/modules/type_support.hpp>
-#include <hpx/runtime_distributed/copy_component.hpp>
 
 #include <hpx/components/containers/partitioned_vector/export_definitions.hpp>
 #include <hpx/components/containers/partitioned_vector/partitioned_vector_component_decl.hpp>

components/containers/partitioned_vector/include/hpx/components/containers/partitioned_vector/partitioned_vector_impl.hpp

@@ -18,7 +18,7 @@
 #include <hpx/modules/errors.hpp>
 #include <hpx/modules/execution.hpp>
 #include <hpx/modules/runtime_components.hpp>
-#include <hpx/runtime_distributed/copy_component.hpp>
+#include <hpx/modules/runtime_distributed.hpp>
 
 #include <hpx/components/containers/partitioned_vector/partitioned_vector_component_impl.hpp>
 #include <hpx/components/containers/partitioned_vector/partitioned_vector_decl.hpp>

components/containers/partitioned_vector/tests/unit/partitioned_vector_subview.cpp

@@ -7,13 +7,15 @@
 #include <hpx/config.hpp>
 #if !defined(HPX_COMPUTE_DEVICE_CODE)
 #include <hpx/collectives/spmd_block.hpp>
-#include <hpx/components/containers/partitioned_vector/partitioned_vector_local_view.hpp>
-#include <hpx/components/containers/partitioned_vector/partitioned_vector_view.hpp>
 #include <hpx/hpx_main.hpp>
+#include <hpx/modules/runtime_distributed.hpp>
+#include <hpx/modules/testing.hpp>
+
 #include <hpx/include/partitioned_vector_predef.hpp>
 #include <hpx/include/partitioned_vector_view.hpp>
-#include <hpx/modules/testing.hpp>
-#include <hpx/runtime_distributed/find_all_localities.hpp>
+
+#include <hpx/components/containers/partitioned_vector/partitioned_vector_local_view.hpp>
+#include <hpx/components/containers/partitioned_vector/partitioned_vector_view.hpp>
 
 #include <cstddef>
 #include <string>

components/containers/partitioned_vector/tests/unit/partitioned_vector_view.cpp

@@ -7,14 +7,16 @@
 #include <hpx/config.hpp>
 #if !defined(HPX_COMPUTE_DEVICE_CODE)
 #include <hpx/collectives/spmd_block.hpp>
-#include <hpx/components/containers/partitioned_vector/partitioned_vector_local_view.hpp>
-#include <hpx/components/containers/partitioned_vector/partitioned_vector_view.hpp>
 #include <hpx/hpx_main.hpp>
-#include <hpx/include/partitioned_vector_predef.hpp>
-#include <hpx/include/partitioned_vector_view.hpp>
 #include <hpx/modules/executors.hpp>
+#include <hpx/modules/runtime_distributed.hpp>
 #include <hpx/modules/testing.hpp>
-#include <hpx/runtime_distributed/find_all_localities.hpp>
+
+#include <hpx/include/partitioned_vector_predef.hpp>
+#include <hpx/include/partitioned_vector_view.hpp>
+
+#include <hpx/components/containers/partitioned_vector/partitioned_vector_local_view.hpp>
+#include <hpx/components/containers/partitioned_vector/partitioned_vector_view.hpp>
 
 #include <cstddef>
 #include <string>

components/containers/partitioned_vector/tests/unit/partitioned_vector_view_iterator.cpp

@@ -8,10 +8,11 @@
 #if !defined(HPX_COMPUTE_DEVICE_CODE)
 #include <hpx/collectives/spmd_block.hpp>
 #include <hpx/hpx_main.hpp>
+#include <hpx/modules/runtime_distributed.hpp>
+#include <hpx/modules/testing.hpp>
+
 #include <hpx/include/partitioned_vector_predef.hpp>
 #include <hpx/include/partitioned_vector_view.hpp>
-#include <hpx/modules/testing.hpp>
-#include <hpx/runtime_distributed/find_all_localities.hpp>
 
 #include <cstddef>
 #include <string>

components/containers/unordered/CMakeLists.txt

@@ -37,5 +37,15 @@ add_hpx_component(
 
 add_hpx_pseudo_dependencies(components.containers.unordered unordered_component)
 
+# MSVC V1951 and V1952 exposes ICE compiling this in C++20 module mode
+if(HPX_WITH_CXX_MODULES
+   AND (CMAKE_CXX_COMPILER_ID STREQUAL "MSVC")
+   AND ((MSVC_VERSION EQUAL 1951) OR (MSVC_VERSION EQUAL 1952))
+)
+  target_compile_definitions(
+    unordered_component PRIVATE HPX_HAVE_FORCE_NO_CXX_MODULES
+  )
+endif()
+
 add_subdirectory(tests)
 add_subdirectory(examples)

components/containers/unordered/include/hpx/components/containers/unordered/unordered_map.hpp

@@ -17,9 +17,9 @@
 #include <hpx/modules/distribution_policies.hpp>
 #include <hpx/modules/functional.hpp>
 #include <hpx/modules/runtime_components.hpp>
+#include <hpx/modules/runtime_distributed.hpp>
 #include <hpx/modules/serialization.hpp>
 #include <hpx/modules/type_support.hpp>
-#include <hpx/runtime_distributed/copy_component.hpp>
 
 #include <hpx/components/containers/unordered/partition_unordered_map_component.hpp>
 #include <hpx/components/containers/unordered/unordered_map_segmented_iterator.hpp>

components/iostreams/CMakeLists.txt

@@ -50,5 +50,15 @@ target_compile_definitions(
 
 add_hpx_pseudo_dependencies(components.iostreams iostreams_component)
 
+# MSVC V1951 and V1952 exposes ICE compiling this in C++20 module mode
+if(HPX_WITH_CXX_MODULES
+   AND (CMAKE_CXX_COMPILER_ID STREQUAL "MSVC")
+   AND ((MSVC_VERSION EQUAL 1951) OR (MSVC_VERSION EQUAL 1952))
+)
+  target_compile_definitions(
+    iostreams_component PRIVATE HPX_HAVE_FORCE_NO_CXX_MODULES
+  )
+endif()
+
 add_subdirectory(tests)
 add_subdirectory(examples)

components/iostreams/src/server/output_stream.cpp

@@ -9,9 +9,9 @@
 #include <hpx/config.hpp>
 #include <hpx/modules/functional.hpp>
 #include <hpx/modules/io_service.hpp>
+#include <hpx/modules/runtime_distributed.hpp>
 #include <hpx/modules/serialization.hpp>
 #include <hpx/modules/threading_base.hpp>
-#include <hpx/runtime_distributed/runtime_fwd.hpp>
 
 #include <hpx/components/iostreams/server/data_buffer.hpp>
 #include <hpx/components/iostreams/server/output_stream.hpp>

components/iostreams/src/standard_streams.cpp

@@ -15,7 +15,7 @@
 #include <hpx/modules/execution.hpp>
 #include <hpx/modules/functional.hpp>
 #include <hpx/modules/logging.hpp>
-#include <hpx/runtime_distributed/runtime_fwd.hpp>
+#include <hpx/modules/runtime_distributed.hpp>
 
 #include <hpx/components/iostreams/ostream.hpp>
 #include <hpx/components/iostreams/standard_streams.hpp>

components/process/CMakeLists.txt

@@ -138,5 +138,15 @@ target_compile_definitions(process_component PRIVATE HPX_PROCESS_EXPORTS)
 
 add_hpx_pseudo_dependencies(components.process process_component)
 
+# MSVC V1951 and V1952 exposes ICE compiling this in C++20 module mode
+if(HPX_WITH_CXX_MODULES
+   AND (CMAKE_CXX_COMPILER_ID STREQUAL "MSVC")
+   AND ((MSVC_VERSION EQUAL 1951) OR (MSVC_VERSION EQUAL 1952))
+)
+  target_compile_definitions(
+    process_component PRIVATE HPX_HAVE_FORCE_NO_CXX_MODULES
+  )
+endif()
+
 add_subdirectory(tests)
 add_subdirectory(examples)

docs/sphinx/manual/writing_distributed_hpx_applications.rst

@@ -897,7 +897,7 @@ An example of how to use the ``partitioned_vector`` container
 with distribution policies would be::
 
     #include <hpx/include/partitioned_vector.hpp>
-    #include <hpx/runtime_distributed/find_localities.hpp>
+    #include <hpx/modules/runtime_distributed.hpp>
 
     // The following code generates all necessary boiler plate to enable the
     // remote creation of 'partitioned_vector' segments