feat: have cmake backend

.github/workflows/CI.yml

@@ -264,6 +264,12 @@ jobs:
       run: |
         ci/run_tests.sh "$PWD/${{ env.FPM_RELEASE }}"
 
+    - name: Test CMake generation
+      if: matrix.toolchain.version == 13
+      shell: bash
+      run: |
+        ci/test_cmake.sh "$PWD/${{ env.FPM_RELEASE }}"
+
     - name: Upload artifact
       uses: actions/upload-artifact@v6
       with:

app/main.f90

@@ -11,6 +11,7 @@ program main
         fpm_update_settings, &
         fpm_clean_settings, &
         fpm_publish_settings, &
+        fpm_generate_settings, &
         get_command_line_settings
 use fpm_error, only: error_t
 use fpm_filesystem, only: exists, parent_dir, join_path
@@ -20,6 +21,7 @@ program main
 use fpm_cmd_new, only: cmd_new
 use fpm_cmd_update, only : cmd_update
 use fpm_cmd_publish, only: cmd_publish
+use fpm_cmd_cmake, only: cmd_generate
 use fpm_os,  only: change_directory, get_current_directory
 
 implicit none
@@ -88,6 +90,8 @@ program main
     call cmd_clean(settings)
 type is (fpm_publish_settings)
     call cmd_publish(settings)
+type is (fpm_generate_settings)
+    call cmd_generate(settings)
 end select
 
 if (allocated(project_root)) then

ci/test_cmake.sh

@@ -0,0 +1,168 @@
+#!/usr/bin/env bash
+
+# Test "fpm generate --cmake" by generating cmake for each example package and
+# then building with the generated CMakeLists.txt
+
+set -u
+
+if [ $# -gt 0 ]; then
+	fpm="$1"
+else
+	fpm=fpm
+fi
+
+build_failures=()
+runtime_failures=()
+
+print_summary_and_exit() {
+	echo "================================"
+	echo "Test Results Summary"
+	echo "================================"
+	if [[ ${#build_failures[@]} -eq 0 ]]; then
+		echo -e "Build failures: \033[0;32mnone\033[0m"
+	else
+		echo -e "Build failures (\033[0;31m${#build_failures[@]}\033[0m):"
+		printf '  %s\n' "${build_failures[@]}"
+	fi
+	echo ""
+	if [[ ${#runtime_failures[@]} -eq 0 ]]; then
+		echo -e "Runtime failures: \033[0;32mnone\033[0m"
+	else
+		echo -e "Runtime failures (\033[0;31m${#runtime_failures[@]}\033[0m):"
+		printf '  %s\n' "${runtime_failures[@]}"
+	fi
+	echo "================================"
+	total_failures=$((${#build_failures[@]} + ${#runtime_failures[@]}))
+	exit $total_failures
+}
+
+# Detect Windows/MSYS2 and set CMake generator accordingly
+CMAKE_GENERATOR_FLAG=""
+if [[ "$OSTYPE" == "msys" ]] || [[ "$OSTYPE" == "win32" ]] || [[ -n "${MSYSTEM:-}" ]]; then
+	# On Windows with MSYS2/MinGW, use MinGW Makefiles generator for Fortran support
+	CMAKE_GENERATOR_FLAG="-G \"MinGW Makefiles\""
+fi
+
+for dir in example_packages/*/ ; do
+
+	# Skip examples that don't work with cmake generation
+	case "$dir" in
+
+		# Does not work with "fpm build" either (intentionally or separate issue)
+		example_packages/features_with_dependency/ )
+			continue
+			;;
+
+		# Require external dependencies not available in CI/CD
+		example_packages/link_external/ | \
+		example_packages/metapackage_blas/ | \
+		example_packages/metapackage_hdf5/ | \
+		example_packages/metapackage_mpi/ | \
+		example_packages/metapackage_mpi_c/ | \
+		example_packages/metapackage_mpi_cpp/ | \
+		example_packages/metapackage_netcdf/ | \
+		example_packages/metapackage_stdlib_extblas/)
+			continue
+			;;
+	esac
+
+	pushd "$dir"
+
+	"$fpm" generate --cmake
+	if [[ $? -ne 0 ]] ; then
+		build_failures+=("$dir (fpm generate failed)")
+		popd
+		continue
+	fi
+	if [[ -n "${CMAKE_GENERATOR_FLAG}" ]]; then
+		eval cmake ${CMAKE_GENERATOR_FLAG} -B temp_cmake_build -S .
+	else
+		cmake -B temp_cmake_build -S .
+	fi
+	cmake --build temp_cmake_build --parallel
+	if [[ $? -ne 0 ]] ; then
+		build_failures+=("$dir")
+	else
+		# Find and run executables. Use maxdepth because dependencies like
+		# test-drive have executable hooks not built by us that I don't want to
+		# run
+		exes=$(find temp_cmake_build -maxdepth 1 -type f -executable)
+		for exe in $exes; do
+
+			[[ "$dir" == "example_packages/fpm_test_exit_code/" ]] && continue  # returns 1 on purpose
+
+			if [[ -x "$exe" ]]; then
+				"$exe"
+				if [[ $? -ne 0 ]]; then
+					runtime_failures+=("$dir : $(basename $exe)")
+				fi
+			fi
+		done
+	fi
+
+	# Cleanup
+	rm -f CMakeLists.txt
+	rm -rf temp_cmake_build
+	# Clean up generated CMakeLists.txt in dependency directories
+	find build/dependencies -name CMakeLists.txt -delete 2>/dev/null || true
+
+	popd
+
+done
+
+echo "================================"
+echo "Testing fpm self-generation with CMake"
+echo "================================"
+
+# Ensure dependencies are fetched first
+"$fpm" build
+if [[ $? -ne 0 ]] ; then
+    build_failures+=("fpm self-generation (fpm build failed)")
+    print_summary_and_exit
+fi
+
+# Generate CMakeLists.txt for fpm itself
+"$fpm" generate --cmake
+if [[ $? -ne 0 ]] ; then
+    build_failures+=("fpm self-generation (generate --cmake failed)")
+    # Cleanup and exit
+    rm -f CMakeLists.txt
+    find build/dependencies -name CMakeLists.txt -delete 2>/dev/null || true
+    print_summary_and_exit
+fi
+
+# Configure and build with CMake
+if [[ -n "${CMAKE_GENERATOR_FLAG}" ]]; then
+    eval cmake ${CMAKE_GENERATOR_FLAG} -B temp_self_cmake_build -S .
+else
+    cmake -B temp_self_cmake_build -S .
+fi
+cmake --build temp_self_cmake_build --parallel
+if [[ $? -ne 0 ]] ; then
+    build_failures+=("fpm self-generation (cmake build failed)")
+    # Cleanup
+    rm -f CMakeLists.txt
+    rm -rf temp_self_cmake_build
+    find build/dependencies -name CMakeLists.txt -delete 2>/dev/null || true
+    print_summary_and_exit
+fi
+
+# Run the CMake-built test suites
+echo "Running CMake-built test suites..."
+for test_exe in temp_self_cmake_build/fpm-test temp_self_cmake_build/cli-test ; do
+    if [[ -x "$test_exe" ]]; then
+        "$test_exe"
+        if [[ $? -ne 0 ]]; then
+            runtime_failures+=("fpm self-generation : $(basename $test_exe)")
+        fi
+    fi
+done
+
+# Cleanup
+rm -f CMakeLists.txt
+rm -rf temp_self_cmake_build
+find build/dependencies -name CMakeLists.txt -delete 2>/dev/null || true
+
+echo "Self-generation test completed"
+
+print_summary_and_exit

example_packages/c_main_preprocess/fpm.toml

@@ -2,6 +2,10 @@ name = "c_main_preprocess"
 [library]
 include-dir = ["src"]
 
+[preprocess]
+[preprocess.cpp]
+macros = ["VAL"]
+
 [[executable]]
 name="main-c"
 main="main.c"

src/fpm.f90

@@ -31,6 +31,7 @@ module fpm
 use iso_c_binding, only: c_char, c_ptr, c_int, c_null_char, c_associated, c_f_pointer
 use fpm_environment, only: os_is_unix, get_os_type, OS_WINDOWS, OS_MACOS, get_env, set_env, delete_env
 use fpm_settings, only: fpm_global_settings, get_global_settings
+use fpm_cmake_check, only: check_cmake_staleness
 
 implicit none
 private
@@ -561,6 +562,12 @@ subroutine cmd_build(settings)
     call fpm_stop(1,'*cmd_build* Model error: '//error%message)
 end if
 
+! Check if CMake files are out of date (after build_model provides source digests)
+if (check_cmake_staleness(model%packages(1)%sources)) then
+    write(stderr, '(a)') "Warning: CMakeLists.txt is out of date with fpm.toml"
+    write(stderr, '(a)') "         Run 'fpm generate --cmake' to regenerate"
+end if
+
 call targets_from_sources(targets, model, settings%prune, package%library, error)
 if (allocated(error)) then
     call fpm_stop(1,'*cmd_build* Target error: '//error%message)
@@ -616,6 +623,12 @@ subroutine cmd_run(settings,test)
         call fpm_stop(1, '*cmd_run* Model error: '//error%message)
     end if
 
+    ! Check if CMake files are out of date (after build_model provides source digests)
+    if (check_cmake_staleness(model%packages(1)%sources)) then
+        write(stderr, '(a)') "Warning: CMakeLists.txt is out of date with fpm.toml"
+        write(stderr, '(a)') "         Run 'fpm generate --cmake' to regenerate"
+    end if
+
     call targets_from_sources(targets, model, settings%prune, package%library, error)
     if (allocated(error)) then
         call fpm_stop(1, '*cmd_run* Targets error: '//error%message)