Avoid empty section_workflow.

nomad/normalizing/workflow.py

@@ -15,6 +15,7 @@
 import numpy as np
 
 from nomad.normalizing.normalizer import Normalizer
+from nomad.datamodel import EntryArchive
 from nomad.datamodel.metainfo.public import Workflow, GeometryOptimization, Phonon, Elastic,\
     MolecularDynamics
 
@@ -344,10 +345,6 @@ class WorkflowNormalizer(Normalizer):
         if self.section_run is None:
             return
 
-        workflow = self.entry_archive.section_workflow
-        if not workflow:
-            workflow = self.entry_archive.m_create(Workflow)
-
         workflow_type = None
         if self.entry_archive.section_workflow:
             workflow_type = self.entry_archive.section_workflow.workflow_type
@@ -358,6 +355,10 @@ class WorkflowNormalizer(Normalizer):
         if not workflow_type:
             return
 
+        workflow = self.entry_archive.section_workflow
+        if not workflow:
+            workflow = self.entry_archive.m_create(Workflow)
+
         workflow.workflow_type = workflow_type
 
         if workflow.workflow_type == 'geometry_optimization':
@@ -371,3 +372,7 @@ class WorkflowNormalizer(Normalizer):
 
         elif workflow.workflow_type == 'molecular_dynamics':
             MolecularDynamicsNormalizer(self.entry_archive).normalize()
+
+        # remove the section workflow again, if the parser/normalizer could not produce a result
+        if workflow.calculation_result_ref is None:
+            self.entry_archive.m_remove_sub_section(EntryArchive.section_workflow, -1)

tests/normalizing/test_workflow.py

@@ -27,6 +27,12 @@ def workflow_archive():
     return _archive
 
 
+def test_no_workflow(workflow_archive):
+    vasp_archive = workflow_archive(
+        'parsers/vaspoutcar', 'tests/data/parsers/vasp_outcar/OUTCAR')
+    assert vasp_archive.section_workflow is None
+
+
 def test_geometry_optimization_workflow(workflow_archive):
     vasp_archive = workflow_archive(
         'parsers/vasp', 'tests/data/normalizers/workflow/vasp/vasprun.xml')