🔥 🐛 Don't pull on input nodes (#318)

* 🔥 🐛 Don't pull on input nodes

A simple call invokes a pull, including pulling the parent tree -- this blows up when the loop is inside a parent scope instead of alone. Since we _know_ these are just user input nodes with direct value connections to the loop macro's scope, we never need to run the pull, or indeed even a fetch the value.

* Format black

---------

Co-authored-by: pyiron-runner <pyiron@mpie.de>

pyiron_workflow/for_loop.py

@@ -273,7 +273,13 @@ def _clean_existing_subgraph(self):
                 # -- it will see data it can work with, but if that data happens to
                 # have the wrong length it may successfully auto-run on the wrong thing
                 # and throw an error!
-                self.children[label]()
+                self.children[label].run(
+                    run_data_tree=False,
+                    run_parent_trees_too=False,
+                    fetch_input=False,
+                    # Data should simply be coming from the value link
+                    # We just want to refresh the output
+                )
         # TODO: Instead of deleting _everything_ each time, try and re-use stuff
 
     def _build_collector_node(self, row_number):

tests/unit/test_for_loop.py

@@ -1,3 +1,4 @@
+import random
 from concurrent.futures import ThreadPoolExecutor
 from itertools import product
 from time import perf_counter
@@ -12,7 +13,9 @@
     MapsToNonexistentOutputError
 )
 from pyiron_workflow.function import as_function_node
-from pyiron_workflow.node_library.standard import Sleep
+from pyiron_workflow.macro import as_macro_node
+from pyiron_workflow.node_library.standard import Add, Sleep
+from pyiron_workflow.transform import inputs_to_list
 
 
 class TestDictionaryToIndexMaps(unittest.TestCase):
@@ -315,6 +318,41 @@ def test_body_node_executor(self):
                 f"Expected limit {grace} x {t_sleep} = {grace * t_sleep} -- got {dt}"
         )
 
+    def test_with_connections(self):
+        length_y = 3
+
+        @as_macro_node()
+        def LoopInside(self, x: list, y: int):
+            self.to_list = inputs_to_list(
+                length_y, y, y, y
+            )
+            self.loop = for_node(
+                Add,
+                iter_on=("obj", "other",),
+                obj=x,
+                other=self.to_list
+            )
+            return self.loop
+
+        x, y = [1], 2
+        li = LoopInside([1], 2)
+        df = li().loop
+        self.assertIsInstance(df, DataFrame)
+        self.assertEqual(length_y * len(x), len(df))
+        self.assertEqual(
+            x[0] + y,
+            df["add"][0],
+            msg="Just make sure the loop is actually running"
+        )
+        x, y = [2, 3], 4
+        df = li(x, y).loop
+        self.assertEqual(length_y * len(x), len(df))
+        self.assertEqual(
+            x[-1] + y,
+            df["add"][len(df) - 1],
+            msg="And make sure that we can vary the length still"
+        )
+
 
 if __name__ == "__main__":
     unittest.main()