build: regenerate params includes at build time via custom command

Author: sbryngelson

CMakeLists.txt

@@ -418,9 +418,9 @@ macro(HANDLE_SOURCES target useCommon)
 
     # Gather:
     # *          src/[<target>,common]/include/*.fpp
-    # * (if any) <build>/include/<target>/*.fpp
-    file(GLOB ${target}_incs CONFIGURE_DEPENDS "${${target}_DIR}/include/*.fpp"
-                                               "${CMAKE_BINARY_DIR}/include/${target}/*.fpp")
+    # * generated includes from build/include/<target>/ (explicit list, not a GLOB)
+    file(GLOB ${target}_incs CONFIGURE_DEPENDS "${${target}_DIR}/include/*.fpp")
+    list(APPEND ${target}_incs ${_mfc_gen_files_${target}})
 
     if (${useCommon})
         file(GLOB common_incs CONFIGURE_DEPENDS "${common_DIR}/include/*.fpp")
@@ -494,6 +494,47 @@ if(_mfc_needs_regen)
     file(TOUCH "${_mfc_gen_stamp}")
 endif()
 
+# Enumerate the 10 generated .fpp files explicitly so ninja can track them as
+# build-time outputs and so HANDLE_SOURCES does not need a configure-time GLOB
+# of ${CMAKE_BINARY_DIR}/include/<target>/ (which fails when the dir is empty).
+set(_mfc_gen_inc "${CMAKE_BINARY_DIR}/include")
+set(_mfc_gen_files_pre_process
+    "${_mfc_gen_inc}/pre_process/generated_namelist.fpp"
+    "${_mfc_gen_inc}/pre_process/generated_decls.fpp"
+    "${_mfc_gen_inc}/pre_process/generated_constants.fpp"
+)
+set(_mfc_gen_files_simulation
+    "${_mfc_gen_inc}/simulation/generated_namelist.fpp"
+    "${_mfc_gen_inc}/simulation/generated_decls.fpp"
+    "${_mfc_gen_inc}/simulation/generated_constants.fpp"
+    "${_mfc_gen_inc}/simulation/generated_case_opt_decls.fpp"
+)
+set(_mfc_gen_files_post_process
+    "${_mfc_gen_inc}/post_process/generated_namelist.fpp"
+    "${_mfc_gen_inc}/post_process/generated_decls.fpp"
+    "${_mfc_gen_inc}/post_process/generated_constants.fpp"
+)
+set(_mfc_gen_files_syscheck)
+set(_mfc_all_gen_files
+    ${_mfc_gen_files_pre_process}
+    ${_mfc_gen_files_simulation}
+    ${_mfc_gen_files_post_process}
+)
+
+# Build-time regeneration: ninja re-runs cmake_gen.py and re-preprocesses
+# any .fpp that includes a generated file whenever a params .py changes.
+add_custom_command(
+    OUTPUT   ${_mfc_all_gen_files}
+    COMMAND  "${Python3_EXECUTABLE}"
+             "${CMAKE_CURRENT_SOURCE_DIR}/toolchain/mfc/params/generators/cmake_gen.py"
+             "${CMAKE_BINARY_DIR}"
+    DEPENDS  ${_mfc_gen_inputs}
+    WORKING_DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}"
+    COMMENT  "Regenerating Fortran parameter includes"
+    VERBATIM
+)
+add_custom_target(mfc_params_gen DEPENDS ${_mfc_all_gen_files})
+
 HANDLE_SOURCES(pre_process ON)
 HANDLE_SOURCES(simulation ON)
 HANDLE_SOURCES(post_process ON)