FIX: loadpkl failed when pklz file contained versioning info

loadpkl called pickle.load at file position 0, which would fail
if the first line of the file was json versioning info (as when
using savepkl with versioning=True). This was fixed by only
seeking to position 0 if no versioning information is found.

Author: pndni-builder

nipype/tests/test_utils.py

@@ -0,0 +1,17 @@
+from nipype import utils
+
+
+def test_pickle(tmp_path):
+    testobj = 'iamateststr'
+    pickle_fname = str(tmp_path / 'testpickle.pklz')
+    utils.filemanip.savepkl(pickle_fname, testobj)
+    outobj = utils.filemanip.loadpkl(pickle_fname)
+    assert outobj == testobj
+
+
+def test_pickle_versioning(tmp_path):
+    testobj = 'iamateststr'
+    pickle_fname = str(tmp_path / 'testpickle.pklz')
+    utils.filemanip.savepkl(pickle_fname, testobj, versioning=True)
+    outobj = utils.filemanip.loadpkl(pickle_fname)
+    assert outobj == testobj

nipype/utils/filemanip.py

@@ -689,8 +689,6 @@ def loadpkl(infile, versioning=False):
             pkl_metadata_line = pkl_file.readline()
             pkl_metadata = json.loads(pkl_metadata_line)
         except (UnicodeDecodeError, json.JSONDecodeError):
-            pass
-        finally:
             # Could not get version info
             pkl_file.seek(0)