Add more advanced cmake macro features to documentation

[SaxenaAnushka102]

BEGINRELEASENOTES

• Add advanced CMake usage for PODIO_GENERATE_DATAMODEL to docs

ENDRELEASENOTES

Fixes #613

[m-fila]

pre-commit complains about the trailing whitespace here

Suggested change

	PODIO_GENERATE_DATAMODEL(newdm newdm.yaml headers sources
	PODIO_GENERATE_DATAMODEL(newdm newdm.yaml headers sources

[tmadlener]

Thanks a lot for this. I have a few suggestions to further improve on this.

[tmadlener]

Suggested change

	1. `UPSTREAM_EDM` - use an existing EDM an upstream dependency. This is useful when your data model extends or builds on top of another one, such as using EDM4hep in [EDM4eic](https://github.com/eic/EDM4eic/blob/7a627488cde0bc4e1863d3fd6bd3396fd30c7296/CMakeLists.txt#L44-L48).
	1. `UPSTREAM_EDM` - use an existing EDM as an upstream dependency. This is useful when your data model extends or builds on top of another one, such as using EDM4hep in [EDM4eic](https://github.com/eic/EDM4eic/blob/7a627488cde0bc4e1863d3fd6bd3396fd30c7296/CMakeLists.txt#L44-L48).

[tmadlener]

Suggested change

	2. `DEPENDS` - tells CMake that some files used to build the data model are not generated during the current build but are still required for compilation, like in [EDM4hep](https://github.com/key4hep/EDM4hep/blob/ac83112d66f7aa3b9d4eb5859c19b987feab3ce5/edm4hep/CMakeLists.txt#L6-L8)
	2. `DEPENDS` - tells CMake that some files used to build the data model are not generated during the current build but are still required for compilation and should trigger a rebuild in case of changes, like in [EDM4hep](https://github.com/key4hep/EDM4hep/blob/ac83112d66f7aa3b9d4eb5859c19b987feab3ce5/edm4hep/CMakeLists.txt#L6-L8)

[tmadlener]

Suggested change

	3. `VERSION` - specifies how to inject the version of the datamodel (it is separate from the schema version).
	3. `VERSION` - specifies the version of the datamodel (it is separate from the schema version). This will be injected into the metadata that is stored in files.

[tmadlener]

Suggested change

	DEPENDS "external_file.yaml;another_dependency.yaml"
	DEPENDS "extra_header.h;more_extras.h"

The main purpose here is to pass in additional c++ files which should become part of the compiled datamodel library.

[SaxenaAnushka102]

Got it, thanks for clarifying!

[tmadlener]

Suggested change

	# Compile the core data model shared library (no I/O)
	PODIO_ADD_DATAMODEL_CORE_LIB(newdm "${headers}" "${sources}")
	# Generate and compile the ROOT I/O dictionary for the default I/O system
	PODIO_ADD_ROOT_IO_DICT(newdmDict newdm "${headers}" src/selection.xml)
	# Compile the SIOBlocks shared library for the SIO backend
	PODIO_ADD_SIO_IO_BLOCKS(newdm "${headers}" "${sources}")

Since these are unchanged wrt the basic examples above and these don't have too many customization points, we can simply remove them here to reduce the "noise" a bit.

[SaxenaAnushka102]

Hi @tmadlener @m-fila, I noticed two checks are failing: pre-commit and sanitizers (gcc13, Address). I've reviewed the logs, but I'm unsure how to resolve the pylint & missing file issues. Will retrying the build solve this? Could you please provide some guidance on what might be going wrong here?

[tmadlener]

The failing CI is unrelated to the changes you made. The sanitizer one wasn't able to download a test file. I am not yet sure what is wrong with pre-commit, but it has been failing for other PRs as well. I am investigating at the moment.

[tmadlener]

If you rebase this onto the latest master branch, CI should fix itself