FIX: Use SyN-SDC if --use-syn-sdc and --ignore fieldmaps are used

Author: effigies

fmriprep/workflows/bold/base.py

@@ -360,6 +360,8 @@ def init_func_preproc_wf(
         fmaps = None
         if 'fieldmaps' not in ignore:
             fmaps = fieldmap_wrangler(layout, ref_file, use_syn=use_syn, force_syn=force_syn)
+        elif use_syn:
+            fmaps = {'syn': True}
 
         # Short circuits: (True and True and (False or 'TooShort')) == 'TooShort'
         run_stc = (bool(metadata.get("SliceTiming")) and