BIDS validation issues: Unsupported BEP004?

[adswa]

I am exploring whether the resulting datasets are BIDS-compliant enough to run fMRIprep on them. I will report on all problems I encounter as issues.

swi modality seems unsupported?

2. The SWI files doesn't seem to comply to the specification

	1: [ERR] Files with such naming scheme are not part of BIDS specification. This error is most commonly caused by typos in file names that make them not BIDS compatible. Please consult the specification and make sure your files are named correctly. If this is not a file naming issue (for example when including files not yet covered by the BIDS specification) you should include a ".bidsignore" file in your dataset (see https://github.com/bids-standard/bids-validator#bidsignore for details). Please note that derived (processed) data should be placed in /derivatives folder and source data (such as DICOMS or behavioural logs in proprietary formats) should be placed in the /sourcedata folder. (code: 1 - NOT_INCLUDED)
		./sub-100****/ses-2/swi/sub-100****_ses-2_part-mag_echo-1_rec-norm_GRE.json
			Evidence: sub-1002708_ses-2_part-mag_echo-1_rec-norm_GRE.json
		./sub-100****/ses-2/swi/sub-100****_ses-2_part-mag_echo-1_rec-norm_GRE.nii.gz
			Evidence: sub-1002708_ses-2_part-mag_echo-1_rec-norm_GRE.nii.gz
		./sub-100****/ses-2/swi/sub-100****_ses-2_part-mag_echo-2_rec-norm_GRE.json
			Evidence: sub-1002708_ses-2_part-mag_echo-2_rec-norm_GRE.json
		./sub-100****/ses-2/swi/sub-100****_ses-2_part-phase_echo-1_GRE.json
			Evidence: sub-1002708_ses-2_part-phase_echo-1_GRE.json
		./sub-100****/ses-2/swi/sub-100****_ses-2_part-phase_echo-2_GRE.json
			Evidence: sub-1002708_ses-2_part-phase_echo-2_GRE.json
		./sub-100****/ses-3/swi/sub-100****_ses-3_part-mag_echo-1_rec-norm_GRE.json
			Evidence: sub-1002708_ses-3_part-mag_echo-1_rec-norm_GRE.json
		./sub-100****/ses-3/swi/sub-100****_ses-3_part-mag_echo-1_rec-norm_GRE.nii.gz
			Evidence: sub-1002708_ses-3_part-mag_echo-1_rec-norm_GRE.nii.gz
		./sub-100****/ses-3/swi/sub-100****_ses-3_part-mag_echo-2_rec-norm_GRE.json
			Evidence: sub-1002708_ses-3_part-mag_echo-2_rec-norm_GRE.json
		./sub-100****/ses-3/swi/sub-100****_ses-3_part-phase_echo-1_GRE.json
			Evidence: sub-1002708_ses-3_part-phase_echo-1_GRE.json
		./sub-100****/ses-3/swi/sub-100****_ses-3_part-phase_echo-2_GRE.json
			Evidence: sub-1002708_ses-3_part-phase_echo-2_GRE.json

It seems as if the naming is compliant to BEP004, but BEP004 hasn't made it into the BIDS specification yet. Adding **/swi/** to the .bidsignore file mentioned in #23 seems like a sensible approach.

[mih]

Given that an ignore file would be located in a single superdataset, I think that solution is fine and maintainable. Once that BEP is merged, only this single file would need to be adjusted.