From fb9e3b06cb8510f4ac47610cdf114ea6cd3c8eaa Mon Sep 17 00:00:00 2001
From: Growl <uwsy1059@qq.com>
Date: Tue, 23 Jun 2026 12:49:46 +0800
Subject: [PATCH] CMake: Make libint2 Fortran interface explicit

---
 cmake/libint2-config.cmake.in |  3 +++
 export/CMakeLists.txt.export  | 36 ++++++++++++++++++++++++-----------
 export/tests/CMakeLists.txt   | 10 ++--------
 3 files changed, 30 insertions(+), 19 deletions(-)

diff --git a/cmake/libint2-config.cmake.in b/cmake/libint2-config.cmake.in
index dce83a3f4..54c4da929 100644
--- a/cmake/libint2-config.cmake.in
+++ b/cmake/libint2-config.cmake.in
@@ -40,6 +40,7 @@
 #   oo - search for           + orca      = orca
 #   bs - search for  bagel    + standard  = bagel
 #   bo - search for           + orca
+#   Fortran - require the Fortran interface target
 
 @PACKAGE_INIT@
 
@@ -55,6 +56,8 @@ list(PREPEND CMAKE_MODULE_PATH ${CMAKE_CURRENT_LIST_DIR})
 # check library language component
 include(CMakeFindDependencyMacro)
 
+set(${L2}_Fortran_FOUND @LIBINT2_ENABLE_FORTRAN@)
+
     if(NOT TARGET Eigen3::Eigen)
       set(Eigen3_CONFIG @Eigen3_CONFIG@)
       if (NOT Eigen3_CONFIG OR NOT EXISTS ${Eigen3_CONFIG})
diff --git a/export/CMakeLists.txt.export b/export/CMakeLists.txt.export
index 5474b1ff1..3e938c8b9 100644
--- a/export/CMakeLists.txt.export
+++ b/export/CMakeLists.txt.export
@@ -125,6 +125,10 @@ set(LIBINT2_INSTALL_DATADIR "${CMAKE_INSTALL_DATADIR}/libint/${LIBINT_VERSION}"
 set(LIBINT2_INSTALL_CMAKEDIR "${CMAKE_INSTALL_LIBDIR}/cmake/libint2"
         CACHE PATH "LIBINT2 CMAKE install directory")
 
+if(NOT CMAKE_INSTALL_Fortran_MODULES)
+    set(CMAKE_INSTALL_Fortran_MODULES "${LIBINT2_INSTALL_INCLUDEDIR}")
+endif()
+
 
 # ====  Dependencies  ===========================================================
 
@@ -668,21 +672,13 @@ if (LIBINT2_ENABLE_FORTRAN)
       )
 
     # build module
-    add_library(
-      libint_f
-      OBJECT
-        fortran/libint_f.F90
-      )
+    add_library(libint_f OBJECT fortran/libint_f.F90)
     set_source_files_properties(
       fortran/libint_f.F90
       PROPERTIES
         OBJECT_DEPENDS "${PROJECT_BINARY_DIR}/fortran/libint2_types_f.h;${PROJECT_BINARY_DIR}/fortran/fortran_incldefs.h"
       )
-    target_compile_definitions(
-      libint_f
-      PRIVATE
-        __COMPILING_LIBINT2
-      )
+    target_compile_definitions(libint_f PRIVATE __COMPILING_LIBINT2)
     set_target_properties(
       libint_f
       PROPERTIES
@@ -700,6 +696,21 @@ if (LIBINT2_ENABLE_FORTRAN)
         $<BUILD_INTERFACE:${PROJECT_BINARY_DIR}/${BUILDTREE_FMODDIR}/>
       )
 
+    add_library(int_f STATIC $<TARGET_OBJECTS:libint_f>)
+    set_target_properties(int_f PROPERTIES OUTPUT_NAME "int2_f")
+    if (L2_BUILD_SHARED_LIBS)
+        target_link_libraries(int_f INTERFACE int-shared)
+    else()
+        target_link_libraries(int_f INTERFACE int-static)
+    endif()
+    target_include_directories(
+      int_f
+      INTERFACE
+        $<BUILD_INTERFACE:${PROJECT_BINARY_DIR}/fortran>
+        $<BUILD_INTERFACE:${PROJECT_BINARY_DIR}/${BUILDTREE_FMODDIR}>
+        $<INSTALL_INTERFACE:${CMAKE_INSTALL_Fortran_MODULES}>
+      )
+
     # Fortran tests merged into rest of tests
 
 endif (LIBINT2_ENABLE_FORTRAN)
@@ -733,6 +744,9 @@ endif()
 if (L2_BUILD_STATIC_LIBS)
     list(APPEND _libint2_install_targets int-static)
 endif()
+if (LIBINT2_ENABLE_FORTRAN)
+    list(APPEND _libint2_install_targets int_f)
+endif()
 
 install(
   TARGETS ${_libint2_install_targets}
@@ -839,7 +853,7 @@ endif()
 if (LIBINT2_ENABLE_FORTRAN)
     install(
       DIRECTORY ${PROJECT_BINARY_DIR}/${BUILDTREE_FMODDIR}/
-      DESTINATION "${LIBINT2_INSTALL_INCLUDEDIR}"
+      DESTINATION "${CMAKE_INSTALL_Fortran_MODULES}"
       )
 endif()
 
diff --git a/export/tests/CMakeLists.txt b/export/tests/CMakeLists.txt
index ca2b48249..4995eec13 100644
--- a/export/tests/CMakeLists.txt
+++ b/export/tests/CMakeLists.txt
@@ -242,10 +242,6 @@ endif (LIBINT2_REQUIRE_CXX_API)
 
 if (LIBINT2_ENABLE_FORTRAN)
 
-    # Note: if forming compile line by hand rather than using targets, you'll
-    #   need to include the Fortran module file directory:
-    #   `target_include_directories(... PRIVATE $<TARGET_PROPERTY:libint_f,Fortran_MODULE_DIRECTORY>)`
-
     add_executable(
       fortran_example-libint2
       EXCLUDE_FROM_ALL
@@ -254,8 +250,7 @@ if (LIBINT2_ENABLE_FORTRAN)
     target_link_libraries(
       fortran_example-libint2
       PRIVATE
-        Libint2::int2
-        libint_f
+        int_f
       )
     add_test(  # Test #14
       NAME libint2/fortran_example/build
@@ -283,14 +278,13 @@ if (LIBINT2_ENABLE_FORTRAN)
           EXCLUDE_FROM_ALL
           fortran/test.cc
           fortran/test-eri.cc
-          $<TARGET_OBJECTS:libint_f>
           )
         target_link_libraries(
           fortran_test-libint2
           PRIVATE
             $<IF:$<TARGET_EXISTS:Libint2::int2-cxx>,Libint2::int2-cxx,Libint2::cxx>
             # N.B. cxx compiled library if LIBINT2_REQUIRE_CXX_API_COMPILED=ON else header-only library
-            libint_f
+            int_f
           )
         add_test(  # Test #16
           NAME libint2/fortran_test/build