FIX: Use load_resultfile when loading a results pickle

Some sections of the code were using ``loadpkl`` which does not resolve
paths.

This PR also improves ``loadpkl`` for readability and reliability.

nipype/pipeline/engine/nodes.py

@@ -194,7 +194,8 @@ def interface(self):
     @property
     def result(self):
         """Get result from result file (do not hold it in memory)"""
-        return _load_resultfile(self.output_dir(), self.name)[0]
+        return _load_resultfile(
+            op.join(self.output_dir(), 'result_%s.pklz' % self.name))[0]
 
     @property
     def inputs(self):
@@ -517,7 +518,7 @@ def _get_inputs(self):
             logger.debug('input: %s', key)
             results_file = info[0]
             logger.debug('results file: %s', results_file)
-            outputs = loadpkl(results_file).outputs
+            outputs = _load_resultfile(results_file)[0].outputs
             if outputs is None:
                 raise RuntimeError("""\
 Error populating the input "%s" of node "%s": the results file of the source node \
@@ -564,7 +565,8 @@ def _run_interface(self, execute=True, updatehash=False):
 
     def _load_results(self):
         cwd = self.output_dir()
-        result, aggregate, attribute_error = _load_resultfile(cwd, self.name)
+        result, aggregate, attribute_error = _load_resultfile(
+            op.join(cwd, 'result_%s.pklz' % self.name))
         # try aggregating first
         if aggregate:
             logger.debug('aggregating results')

nipype/pipeline/engine/utils.py

@@ -16,7 +16,6 @@
 
 from traceback import format_exception
 from hashlib import sha1
-import gzip
 
 from functools import reduce
 
@@ -25,6 +24,7 @@
 
 from ... import logging, config, LooseVersion
 from ...utils.filemanip import (
+    Path,
     relpath,
     makedirs,
     fname_presuffix,
@@ -34,6 +34,7 @@
     FileNotFoundError,
     save_json,
     savepkl,
+    loadpkl,
     write_rst_header,
     write_rst_dict,
     write_rst_list,
@@ -308,7 +309,7 @@ def save_resultfile(result, cwd, name):
             setattr(result.outputs, k, v)
 
 
-def load_resultfile(path, name):
+def load_resultfile(results_file):
     """
     Load InterfaceResult file from path
 
@@ -328,17 +329,14 @@ def load_resultfile(path, name):
         rerun
     """
     aggregate = True
-    resultsoutputfile = os.path.join(path, 'result_%s.pklz' % name)
+    results_file = Path(results_file)
+    path = '%s' % results_file.parents
+
     result = None
     attribute_error = False
-    if os.path.exists(resultsoutputfile):
-        pkl_file = gzip.open(resultsoutputfile, 'rb')
+    if results_file.exists():
         try:
-            result = pickle.load(pkl_file)
-        except UnicodeDecodeError:
-            # Was this pickle created with Python 2.x?
-            pickle.load(pkl_file, fix_imports=True, encoding='utf-8')
-            logger.warning('Successfully loaded pkl in compatibility mode')
+            result = loadpkl(results_file)
         except (traits.TraitError, AttributeError, ImportError,
                 EOFError) as err:
             if isinstance(err, (AttributeError, ImportError)):
@@ -362,7 +360,6 @@ def load_resultfile(path, name):
                     logger.debug('conversion to full path results in '
                                  'non existent file')
             aggregate = False
-        pkl_file.close()
     logger.debug('Aggregate: %s', aggregate)
     return result, aggregate, attribute_error
 

nipype/pipeline/plugins/base.py

@@ -18,9 +18,8 @@
 import numpy as np
 
 from ... import logging
-from ...utils.filemanip import loadpkl
 from ...utils.misc import str2bool
-from ..engine.utils import topological_sort
+from ..engine.utils import topological_sort, load_resultfile
 from ..engine import MapNode
 from .tools import report_crash, report_nodes_not_run, create_pyscript
 
@@ -504,7 +503,7 @@ def _get_result(self, taskid):
                 result_data['traceback'] = '\n'.join(format_exception(*sys.exc_info()))
         else:
             results_file = glob(os.path.join(node_dir, 'result_*.pklz'))[0]
-            result_data = loadpkl(results_file)
+            result_data = load_resultfile(results_file)
         result_out = dict(result=None, traceback=None)
         if isinstance(result_data, dict):
             result_out['result'] = result_data['result']
@@ -602,7 +601,7 @@ def _get_result(self, taskid):
         glob(os.path.join(node_dir, 'result_*.pklz')).pop()
 
         results_file = glob(os.path.join(node_dir, 'result_*.pklz'))[0]
-        result_data = loadpkl(results_file)
+        result_data = load_resultfile(results_file)
         result_out = dict(result=None, traceback=None)
 
         if isinstance(result_data, dict):

nipype/utils/filemanip.py

@@ -676,52 +676,50 @@ def loadcrash(infile, *args):
 
 
 def loadpkl(infile, versioning=False):
-    """Load a zipped or plain cPickled file
-    """
+    """Load a zipped or plain cPickled file."""
+    infile = Path(infile)
     fmlogger.debug('Loading pkl: %s', infile)
-    if infile.endswith('pklz'):
-        pkl_file = gzip.open(infile, 'rb')
-    else:
-        pkl_file = open(infile, 'rb')
+    pklopen = gzip.open if infile.suffix == '.pklz' else open
+    pkl_metadata = None
 
-    if versioning:
-        pkl_metadata = {}
+    with indirectory(str(infile.parent)):
+        pkl_file = pklopen(infile.name, 'rb')
 
-        # Look if pkl file contains version file
-        try:
+        try:  # Look if pkl file contains version file
             pkl_metadata_line = pkl_file.readline()
             pkl_metadata = json.loads(pkl_metadata_line)
-        except:
+        except UnicodeDecodeError:
+            pass
+        finally:
             # Could not get version info
             pkl_file.seek(0)
 
-    try:
         try:
             unpkl = pickle.load(pkl_file)
         except UnicodeDecodeError:
+            # Was this pickle created with Python 2.x?
             unpkl = pickle.load(pkl_file, fix_imports=True, encoding='utf-8')
-
-        return unpkl
-
-    # Unpickling problems
-    except Exception as e:
-        if not versioning:
+            fmlogger.info('Successfully loaded pkl in compatibility mode.')
+        # Unpickling problems
+        except Exception as e:
+            if not versioning:
+                raise e
+
+            if pkl_metadata and 'version' in pkl_metadata:
+                from nipype import __version__ as version
+                if pkl_metadata['version'] != version:
+                    fmlogger.error("""\
+Attempted to open a results file generated by Nipype version %s, \
+with an incompatible Nipype version (%s)""", pkl_metadata['version'], version)
+                    raise e
+            fmlogger.error("""\
+No metadata was found in the pkl file. Make sure you are currently using \
+the same Nipype version from the generated pkl.""")
             raise e
-
-        from nipype import __version__ as version
-
-        if 'version' in pkl_metadata:
-            if pkl_metadata['version'] != version:
-                fmlogger.error('Your Nipype version is: %s',
-                               version)
-                fmlogger.error('Nipype version of the pkl is: %s',
-                               pkl_metadata['version'])
         else:
-            fmlogger.error('No metadata was found in the pkl file.')
-            fmlogger.error('Make sure that you are using the same Nipype'
-                           'version from the generated pkl.')
-
-        raise e
+            return unpkl
+        finally:
+            pkl_file.close()
 
 
 def crash2txt(filename, record):