Merge pull request #17901 from mvdbeek/fix_workflow_saving

[23.2] Fix saving workflows with freehand_comments only

lib/galaxy/workflow/steps.py

@@ -2,6 +2,7 @@
 workflow steps.
 """
 import math
+from itertools import chain
 
 from galaxy.util.topsort import (
     CycleError,
@@ -57,16 +58,16 @@ def order_workflow_steps(steps, comments):
                 else:
                     sortable_comments.append(comment)
 
-            # consider comments to find normalization position
-            min_left_comments = min(comment.position[0] for comment in sortable_comments)
-            min_top_comments = min(comment.position[1] for comment in sortable_comments)
-            min_left = min(min_left_comments, min_left)
-            min_top = min(min_top_comments, min_top)
+            if sortable_comments:
+                # consider comments to find normalization position
+                min_left_comments = min(comment.position[0] for comment in sortable_comments)
+                min_top_comments = min(comment.position[1] for comment in sortable_comments)
+                min_left = min(min_left_comments, min_left)
+                min_top = min(min_top_comments, min_top)
 
             # normalize comments by min_left and min_top
-            for comment_list in [sortable_comments, freehand_comments]:
-                for comment in comment_list:
-                    comment.position = [comment.position[0] - min_left, comment.position[1] - min_top]
+            for comment in chain(sortable_comments, freehand_comments):
+                comment.position = [comment.position[0] - min_left, comment.position[1] - min_top]
 
             # order by Euclidean distance to the origin
             sortable_comments.sort(key=lambda comment: math.sqrt(comment.position[0] ** 2 + comment.position[1] ** 2))