bids.BIDSLayout.build_path() discards dir- label for dwi images

[ajschadler12]

Preamble

pybids version: bids.__version__ --> '0.15.2'

Issue is referenced with example code in this neurostars thread.

Issue is confirmed to not affect bold or epi files.

Issue

Current Behavior

• Use bids.BIDSLayout.build_path() to generate valid filenames from modified entities from a DWI image.
  • original filename: sub-01_ses-1_dir-AP_dwi.nii.gz
• Modified name is stripped of dir-AP label.
  • modified filename: sub-1_ses-1_acq-modified_dwi.nii.gz

Desired Behavior

• Return generated filename with relevant dir- labels:
  • sub-1_ses-1_acq-modified_dir-AP_dwi.nii.gz

Possible Causes:

• layout/config/bids.json is missing [_dir-{direction}] for the dwi line in default_path_patterns.
  • Update dwi entry to 'sub-{subject}[/ses-{session}]/dwi/sub-{subject}[_ses-{session}][_acq-{acquisition}][_dir-{direction}]_{suffix<dwi>}.{extension<bval|bvec|json|nii.gz|nii>|nii.gz}' in `bids.json