fix: explicitly use SELECTION_XML in OUTPUT_FOLDER

[wdconinc]

After checking that ${ARG_OUTPUT_FOLDER}/${SELECTION_XML} exists, we should not simply pass ${SELECTION_XML} to PODIO_GENERATE_DICTIONARY, but pass the full path for when ${ARG_OUTPUT_FOLDER} is not ${CMAKE_CURRENT_SOURCE_DIR}.

BEGINRELEASENOTES

• CMake: PODIO_ADD_ROOT_IO_DICT: Bugfix for data models in OUTPUT_FOLDER not equal to source dir in root dictionary generation cmake macro.
  • Now SELECTION_XML can be passed either as absolute path or relative to OUTPUT_FOLDER.

ENDRELEASENOTES

[tmadlener]

Good catch. Thank you.
Tow minor things (I can also fix those, just let me know. I should be able to push directly to the PR branch usually)

• Could you also update the docstring of the macro to include that SELECTION_XML is relative to OUTPUT_FOLDER?
• The podio internal tests of the extenstion datamodel also do not seem to get this correct here:

  podio/tests/CMakeLists.txt

  Lines 199 to 200 in d0d4f67

  	PODIO_ADD_ROOT_IO_DICT(ExtensionDataModelDict ExtensionDataModel "${ext_headers}" ${CMAKE_CURRENT_SOURCE_DIR}/extension_model/src/selection.xml
  	OUTPUT_FOLDER ${CMAKE_CURRENT_SOURCE_DIR}/extension_model)

[wdconinc]

Could you also update the docstring of the macro to include that SELECTION_XML is relative to OUTPUT_FOLDER?

We could also allow both relative and absolute paths to selection file and use cmake to figure which it is, similar to https://github.com/AIDASoft/podio/blob/master/cmake/podioMacros.cmake#L29-L34.

The other approach could be to change the test for existence of the selection.xml in https://github.com/AIDASoft/podio/blob/master/cmake/podioMacros.cmake#L273-L276 to something like

  IF (NOT EXISTS ${ARG_OUTPUT_FOLDER}/${SELECTION_XML}
  AND NOT EXISTS ${SELECTION_XML})
    MESSAGE(STATUS "Not adding the ROOT dictionary to the targets because the selection.xml has not been generated")
    RETURN()
  ENDIF()

I'll let you fix this in whichever way you think best.

[tmadlener]

Thanks for the IS_ABSOLUTE hint. Now SELECTION_XML can either be absolute or relative to OUTPUT_FOLDER. Also updated the documentation and made the status message a bit more informative.

[tmadlener]

dev4/x86_64-centos7-gcc11-opt seems to be broken entirely, we pick up the default cmake from CentOS7.