[BUG] The function define_participants return value is not deterministic

[NicolasGensollen]

The following function:

clinica/clinica/iotools/converters/ixi_to_bids/ixi_to_bids_utils.py

Lines 48 to 80 in 2623ab5

	def define_participants(
	data_directory: Path,
	subjs_list_path: Optional[Path] = None,
	) -> List[str]:
	"""
	Defines the actual list of participants based on the (provided) subjects list filtered
	using existing data.
	Parameters
	----------
	data_directory : Path to the raw data directory.
	subjs_list_path : [Optional] Path to a text file containing a list of specific subjects to extract.
	Returns
	-------
	The list of ids that were either present in the data directory or asked for with a specific text file, provided
	associated images actually exists.
	"""
	list_from_data = _get_subjects_list_from_data(data_directory)
	if subjs_list_path is None:
	return list_from_data
	cprint("Loading a subjects list provided by the user...")
	list_from_file = _get_subjects_list_from_file(subjs_list_path)
	list_filtered = [subject for subject in list_from_file if subject in list_from_data]
	invalid_subjects = list(set(list_from_file) - set(list_filtered))
	if invalid_subjects:
	cprint(
	f"The subjects : {' , '.join(invalid_subjects)} do not have any associated data inside the directory {data_directory}"
	f" and can not be converted."
	)
	return list_filtered

is not fully deterministic and the order of the returned subject labels may vary as can be seen here:

https://github.com/aramis-lab/clinica/actions/runs/11251994838/job/31284194042?pr=1316

We need to make sure the order is deterministic, for example by sorting prior to returning.

@AliceJoubert WDYT ?

[NicolasGensollen]

Solved by #1318