fix+tst: --files heuristic flexiblility

Author: mgxd

heudiconv/parser.py

@@ -167,20 +167,6 @@ def get_study_sessions(dicom_dir_template, files_opt, heuristic, outdir,
             dcmfilter=getattr(heuristic, 'filter_dicom', None),
             grouping=grouping)
 
-        if not getattr(heuristic, 'infotoids', None):
-            lgr.warn("Heuristic is missing an `infotoids` method, assigning "
-                     "empty method. For best results, define an `infotoids`")
-            def infotoids(seqinfos, outdir):
-                return {
-                    'locator': None,
-                    'session': None,
-                    'subject': None
-                    }
-            heuristic.infotoids = infotoids
-            # raise NotImplementedError(
-            #     "For now, if no subj template is provided, requiring "
-            #     "heuristic to have infotoids")
-
         if sids:
             if not (len(sids) == 1 and len(seqinfo_dict) == 1):
                 raise RuntimeError(
@@ -193,6 +179,23 @@ def infotoids(seqinfos, outdir):
         else:
             sid = None
 
+        if not getattr(heuristic, 'infotoids', None):
+            # allow bypass with subject override
+            if not sid:
+                raise NotImplementedError("Cannot guarantee subject id - add "
+                                          "`infotoids` to heuristic file or "
+                                          "provide `--subject` argument")
+            lgr.warn("Heuristic is missing an `infotoids` method, assigning "
+                     "empty method and using provided subject id", sid,
+                     "Provide `session` and `locator` fields for best results.")
+            def infotoids(seqinfos, outdir):
+                return {
+                    'locator': None,
+                    'session': None,
+                    'subject': None
+                    }
+            heuristic.infotoids = infotoids
+
         for studyUID, seqinfo in seqinfo_dict.items():
             # so we have a single study, we need to figure out its
             # locator, session, subject

heudiconv/tests/test_heuristics.py

@@ -64,9 +64,12 @@ def test_reproin_largely_smoke(tmpdir, heuristic, invocation):
             runner(args + ['--subjects', 'sub1', 'sub2'])
 
         if heuristic != 'reproin':
-            # none other heuristic has mighty infotoids atm
+            # if subject is not overriden, raise error
             with pytest.raises(NotImplementedError):
                 runner(args)
+
+            # but run successful when provided
+            runner(args + ['--subjects', 'sub1'])
             return
     runner(args)
     ds = Dataset(str(tmpdir))