--- a/hgext3rd/evolve/templatekw.py	Thu Jun 29 16:49:33 2017 +0200
+++ b/hgext3rd/evolve/templatekw.py	Mon Jun 26 17:19:03 2017 +0200
@@ -140,10 +140,12 @@
         'obsfate_verbose': verbtempl + usertempl + succtempl + datetempl,
     }
 
-@eh.templatekw("obsfate")
-def showobsfate(repo, ctx, **args):
+def obsfatedata(repo, ctx):
+    """compute the raw data needed for computing obsfate
+    Returns a list of dict
+    """
     if not ctx.obsolete():
-        return ''
+        return None
 
     successorssets, pathcache = closestsuccessors(repo, ctx.node())
 
@@ -172,7 +174,20 @@
     values = []
     for sset, rawmarkers in fullsuccessorsets:
         raw = obshistory.preparesuccessorset(sset, rawmarkers)
+        values.append(raw)
 
+    return values
+
+@eh.templatekw("obsfate")
+def showobsfate(repo, ctx, **args):
+    # Get the needed obsfate data
+    values = obsfatedata(repo, ctx)
+
+    if values is None:
+        return ''
+
+    # Format each successorset successors list
+    for raw in values:
         # As we can't do something like
         # "{join(map(nodeshort, successors), ', '}" in template, manually
         # create a correct textual representation
@@ -183,8 +198,7 @@
         raw['successors'] = templatekw._hybrid(gen, raw['successors'], makemap,
                                                joinfmt)
 
-        values.append(raw)
-
+    # And then format them
     # Insert default obsfate templates
     args['templ'].cache.update(obsfatedefaulttempl(repo.ui))