only add dune modules that have python bindings as requirements in setup.py.in

This requires an addition module_HASPYTHON flag in module-config.cmake

add a MODULE_HASPYTHON variable

cmake/modules/DuneMacros.cmake

@@ -777,6 +777,7 @@ set(${ProjectName}_DEPENDS \"@${ProjectName}_DEPENDS@\")
 set(${ProjectName}_SUGGESTS \"@${ProjectName}_SUGGESTS@\")
 set(${ProjectName}_MODULE_PATH \"@PACKAGE_DUNE_INSTALL_MODULEDIR@\")
 set(${ProjectName}_LIBRARIES \"@DUNE_MODULE_LIBRARIES@\")
+set(${ProjectName}_HASPYTHON @DUNE_MODULE_HASPYTHON@)
 
 # Lines that are set by the CMake build system via the variable DUNE_CUSTOM_PKG_CONFIG_SECTION
 ${DUNE_CUSTOM_PKG_CONFIG_SECTION}
@@ -786,6 +787,7 @@ if(${ProjectName}_LIBRARIES)
   get_filename_component(_dir \"\${CMAKE_CURRENT_LIST_FILE}\" PATH)
   include(\"\${_dir}/${ProjectName}-targets.cmake\")
 endif()
+
 endif()")
       set(CONFIG_SOURCE_FILE ${PROJECT_BINARY_DIR}/CMakeFiles/${ProjectName}-config.cmake.in)
   else()
@@ -809,6 +811,11 @@ endif()")
   # file section of dune-grid.
   set(DUNE_MODULE_SRC_DOCDIR "${PROJECT_SOURCE_DIR}/doc")
   set(MODULE_INSTALLED ON)
+  if(EXISTS ${PROJECT_SOURCE_DIR}/python)
+    set(DUNE_MODULE_HASPYTHON 1)
+  else()
+    set(DUNE_MODULE_HASPYTHON 0)
+  endif()
 
   configure_package_config_file(${CONFIG_SOURCE_FILE}
     ${PROJECT_BINARY_DIR}/cmake/pkg/${ProjectName}-config.cmake
@@ -833,6 +840,7 @@ macro(set_and_check _var _file)
   endif()
 endmacro()")
   set(MODULE_INSTALLED OFF)
+
   configure_file(
     ${CONFIG_SOURCE_FILE}
     ${PROJECT_BINARY_DIR}/${ProjectName}-config.cmake @ONLY)

cmake/modules/DunePythonInstallPackage.cmake

@@ -65,6 +65,14 @@ function(dune_python_install_package)
   endif()
 
   # Configure setup.py.in if present
+
+  set(RequiredPythonModules "${ProjectPythonRequires}")
+  foreach(mod ${ALL_DEPENDENCIES})
+    if(${${mod}_HASPYTHON}) # module found and has python bindings
+      string(APPEND RequiredPythonModules " ${mod}")
+    endif()
+  endforeach()
+
   set(PYINST_FULLPATH ${CMAKE_CURRENT_SOURCE_DIR}/${PYINST_PATH})
   if(EXISTS ${PYINST_FULLPATH}/setup.py.in)
     configure_file(${PYINST_PATH}/setup.py.in ${PYINST_PATH}/setup.py)

cmake/pkg/dune-common-config.cmake.in

@@ -19,5 +19,6 @@ set_and_check(DOXYSTYLE_FILE "@PACKAGE_DOXYSTYLE_DIR@/Doxystyle")
 set_and_check(DOXYGENMACROS_FILE "@PACKAGE_DOXYSTYLE_DIR@/doxygen-macros")
 set(@DUNE_MOD_NAME@_DEPENDS "@DUNE_DEPENDS@")
 set(@DUNE_MOD_NAME@_SUGGESTS "@DUNE_SUGGESTS@")
+set(@DUNE_MOD_NAME@_HASPYTHON 1)
 set_and_check(@DUNE_MOD_NAME@_MODULE_PATH "@PACKAGE_DUNE_INSTALL_MODULEDIR@")
 endif(NOT @DUNE_MOD_NAME@_FOUND)

python/CMakeLists.txt

@@ -7,7 +7,6 @@ add_subdirectory(dune)
 # endif()
 
 configure_file(MANIFEST.in MANIFEST.in)
-configure_file(setup.py.in setup.py)
 configure_file(pyproject.toml.in pyproject.toml)
 
 dune_python_install_package(

python/dune/packagemetadata.py

@@ -409,9 +409,9 @@ class MetaDataDict(dict):
                 result[k] = v
         return result
     def unique_value_across_modules(self,key, default=""):
-        values = set(m[key] for m in self.values())
+        values = set(m[key] for m in self.values() if not m[key] == "")
         if len(values) > 1:
-            raise ValueError(f"Key {key} is expected to be unique across the given metadata")
+            raise ValueError(f"Key {key} is expected to be unique across the given metadata. Got {values}")
         if len(values) == 0:
             return default
         value, = values

python/setup.py.in

 from setuptools import setup, find_namespace_packages
 
-pkg = '${ProjectPythonRequires} ${ALL_DEPENDENCIES}'.replace(';',' ').split(' ')
+pkg = '${RequiredPythonModules}'.replace(';',' ').split(' ')
 
 setup(name="${ProjectName}",
     # only add 'dune' here in dune-common other packages shouldn't add file # directly to 'dune'