fix: previous node data provider returns wrong result when inside an iteration (baserow#5009)

* Fix bad iteration result when multiple nodes

Author: jrmi

backend/src/baserow/contrib/automation/automation_dispatch_context.py

@@ -3,7 +3,10 @@
 from baserow.contrib.automation.data_providers.registries import (
     automation_data_provider_type_registry,
 )
-from baserow.contrib.automation.history.models import AutomationNodeResult
+from baserow.contrib.automation.history.handler import AutomationHistoryHandler
+from baserow.contrib.automation.history.models import (
+    AutomationNodeHistory,
+)
 from baserow.contrib.automation.nodes.models import AutomationActionNode
 from baserow.contrib.automation.workflows.models import AutomationWorkflow
 from baserow.core.cache import local_cache
@@ -13,12 +16,12 @@
 
 
 class AutomationDispatchContext(DispatchContext):
-    own_properties = ["workflow", "event_payload", "history_id"]
+    own_properties = ["workflow", "event_payload", "history"]
 
     def __init__(
         self,
         workflow: AutomationWorkflow,
-        history_id: int,
+        history: AutomationNodeHistory,
         event_payload: Optional[Union[Dict, List[Dict]]] = None,
         simulate_until_node: Optional[AutomationActionNode] = None,
         current_iterations: Optional[Dict[int, int]] = None,
@@ -29,7 +32,7 @@ def __init__(
         node's changes.
 
         :param workflow: The workflow that this dispatch context is associated with.
-        :param history_id: The AutomationWorkflowHistory ID from which the
+        :param history: The AutomationWorkflowHistory from which the
             workflow's event payload and node results are derived.
         :param event_payload: The event data from the trigger node, if any was
             provided, as this is optional.
@@ -39,7 +42,7 @@ def __init__(
         """
 
         self.workflow = workflow
-        self.history_id = history_id
+        self.history = history
         self.simulate_until_node = simulate_until_node
         self.current_iterations: Dict[int, int] = {}
 
@@ -72,36 +75,30 @@ def clone(self, **kwargs):
         new_context.current_iterations = {**self.current_iterations}
         return new_context
 
-    def _get_previous_results_cache_key(self) -> Optional[str]:
-        return f"wa_previous_nodes_results_{self.history_id}"
-
-    def _load_previous_results(self) -> Dict[int, Any]:
+    def get_iteration_path(self, node):
         """
-        Returns a dict where keys are the node IDs and values are the results
-        of the previous_nodes_results.
+        Compute the current iteration path for the given node.
         """
+        parent_nodes = node.get_parent_nodes()
 
-        results = {}
-        previous_results = AutomationNodeResult.objects.filter(
-            node_history__workflow_history_id=self.history_id
-        ).select_related("node_history__node")
-        for result in previous_results:
-            results[result.node_history.node_id] = result.result
+        return ".".join([str(self.current_iterations[p.id]) for p in parent_nodes])
 
-        return results
+    def _get_previous_result_cache_key(self, node) -> Optional[str]:
+        return f"wa_previous_node_result_{self.history.id}_{node.id}"
 
     @property
     def data_provider_registry(self):
         return automation_data_provider_type_registry
 
-    @property
-    def previous_nodes_results(self) -> Dict[int, Any]:
-        if cache_key := self._get_previous_results_cache_key():
-            return local_cache.get(
-                cache_key,
-                lambda: self._load_previous_results(),
-            )
-        return {}
+    def get_previous_node_result(self, node) -> Dict[int, Any]:
+        # We don't need to cache per iteration path because it won't change in this
+        # dispatch
+        return local_cache.get(
+            self._get_previous_result_cache_key(node),
+            lambda: AutomationHistoryHandler().get_node_result(
+                self.history, node, self.get_iteration_path(node)
+            ),
+        )
 
     def get_timezone_name(self) -> str:
         """
@@ -120,17 +117,21 @@ def sortings(self) -> Optional[str]:
     def filters(self) -> Optional[str]:
         return None
 
+    @property
     def is_publicly_sortable(self) -> bool:
         return False
 
+    @property
     def is_publicly_filterable(self) -> bool:
         return False
 
+    @property
     def is_publicly_searchable(self) -> bool:
         return False
 
+    @property
     def public_allowed_properties(self) -> Optional[Dict[str, Dict[int, List[str]]]]:
-        return {}
+        return None
 
     def search_query(self) -> Optional[str]:
         return None

backend/src/baserow/contrib/automation/data_providers/data_provider_types.py

@@ -4,6 +4,9 @@
 from baserow.contrib.automation.automation_dispatch_context import (
     AutomationDispatchContext,
 )
+from baserow.contrib.automation.history.exceptions import (
+    AutomationWorkflowHistoryNodeResultDoesNotExist,
+)
 from baserow.contrib.automation.nodes.exceptions import AutomationNodeDoesNotExist
 from baserow.contrib.automation.nodes.handler import AutomationNodeHandler
 from baserow.core.formula.exceptions import InvalidFormulaContext
@@ -33,10 +36,10 @@ def get_data_chunk(
             raise InvalidFormulaContext(message) from exc
 
         try:
-            previous_node_results = dispatch_context.previous_nodes_results[
-                int(previous_node.id)
-            ]
-        except KeyError as exc:
+            previous_node_result = dispatch_context.get_previous_node_result(
+                previous_node
+            )
+        except AutomationWorkflowHistoryNodeResultDoesNotExist as exc:
             message = (
                 "The previous node id is not present in the dispatch context results"
             )
@@ -45,7 +48,7 @@ def get_data_chunk(
         service = previous_node.service.specific
 
         if service.get_type().returns_list:
-            previous_node_results = previous_node_results["results"]
+            previous_node_result = previous_node_result["results"]
             if len(rest) >= 2:
                 prepared_path = [
                     rest[0],
@@ -56,7 +59,7 @@ def get_data_chunk(
         else:
             prepared_path = service.get_type().prepare_value_path(service, rest)
 
-        return get_value_at_path(previous_node_results, prepared_path)
+        return get_value_at_path(previous_node_result, prepared_path)
 
     def import_path(self, path, id_mapping, **kwargs):
         """
@@ -99,9 +102,7 @@ def get_data_chunk(
             raise InvalidFormulaContext(message) from exc
 
         try:
-            parent_node_results = dispatch_context.previous_nodes_results[
-                parent_node.id
-            ]
+            parent_node_result = dispatch_context.get_previous_node_result(parent_node)
         except KeyError as exc:
             message = (
                 "The parent node id is not present in the dispatch context results"
@@ -116,7 +117,7 @@ def get_data_chunk(
             )
             raise InvalidFormulaContext(message) from exc
 
-        current_item = parent_node_results["results"][current_iteration]
+        current_item = parent_node_result["results"][current_iteration]
         data = {"index": current_iteration, "item": current_item}
 
         return get_value_at_path(data, rest)

backend/src/baserow/contrib/automation/history/exceptions.py

@@ -15,3 +15,7 @@ def __init__(self, history_id=None, *args, **kwargs):
             *args,
             **kwargs,
         )
+
+
+class AutomationWorkflowHistoryNodeResultDoesNotExist(AutomationWorkflowHistoryError):
+    """When the result entry doesn't exist for the given node/history."""

backend/src/baserow/contrib/automation/history/handler.py

@@ -6,6 +6,7 @@
 from baserow.contrib.automation.history.constants import HistoryStatusChoices
 from baserow.contrib.automation.history.exceptions import (
     AutomationWorkflowHistoryDoesNotExist,
+    AutomationWorkflowHistoryNodeResultDoesNotExist,
 )
 from baserow.contrib.automation.history.models import (
     AutomationNodeHistory,
@@ -105,13 +106,29 @@ def create_node_result(
         self,
         node_history: AutomationNodeHistory,
         result: Optional[Union[Dict, List[Dict]]] = None,
-        iteration: int = 0,
+        iteration_path: str = "",
     ) -> AutomationNodeResult:
         """Saves the result of a Node dispatch."""
 
         result = result if result else {}
         return AutomationNodeResult.objects.create(
             node_history=node_history,
-            iteration=iteration,
+            iteration_path=iteration_path,
             result=result,
         )
+
+    def get_node_result(self, history, node, iteration_path):
+        """
+        Returns the result for the given history/node/iteration_path.
+        """
+
+        try:
+            node_result = AutomationNodeResult.objects.only("result").get(
+                node_history__workflow_history_id=history.id,
+                node_history__node_id=node.id,
+                iteration_path=iteration_path,
+            )
+        except AutomationNodeResult.DoesNotExist:
+            raise AutomationWorkflowHistoryNodeResultDoesNotExist()
+
+        return node_result.result

backend/src/baserow/contrib/automation/history/models.py

@@ -9,10 +9,6 @@ class AutomationHistory(models.Model):
 
     message = models.TextField()
 
-    is_test_run = models.BooleanField(
-        db_default=False
-    )  # TODO ZDM: Remove after next release
-
     status = models.CharField(
         choices=HistoryStatusChoices.choices,
         max_length=8,
@@ -78,6 +74,12 @@ class AutomationNodeResult(models.Model):
     iteration = models.PositiveIntegerField(
         db_default=0,
         help_text="Keeps track of the current iteration of the Iterator node.",
+    )  # TODO ZDM: Remove after next release
+
+    iteration_path = models.CharField(
+        db_default="",
+        default="",
+        help_text="Keeps track of the iteration path that generated the result.",
     )
 
     result = models.JSONField(

backend/src/baserow/contrib/automation/migrations/0025_automationnoderesult_iteration_path.py

@@ -0,0 +1,32 @@
+# Generated by Django 5.2.12 on 2026-03-19 10:23
+
+from django.db import migrations, models
+from django.db.models import CharField
+from django.db.models.functions import Cast
+
+
+def populate_iteration_path(apps, schema_editor):
+    AutomationNodeResult = apps.get_model("automation", "AutomationNodeResult")
+    AutomationNodeResult.objects.update(
+        iteration_path=Cast("iteration", output_field=CharField())
+    )
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('automation', '0024_automationworkflowhistory_event_payload_and_more'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='automationnoderesult',
+            name='iteration_path',
+            field=models.CharField(db_default='', default='', help_text='Keeps track of the iteration path that generated the result.'),
+        ),
+        migrations.RunPython(populate_iteration_path, migrations.RunPython.noop),
+        migrations.RemoveField(
+            model_name='automationnodehistory',
+            name='is_test_run',
+        ),
+    ]

backend/src/baserow/contrib/automation/nodes/handler.py

@@ -449,7 +449,7 @@ def dispatch_node(
 
         dispatch_context = AutomationDispatchContext(
             node.workflow,
-            history_id,
+            workflow_history,
             event_payload=workflow_history.event_payload,
             simulate_until_node=workflow_history.simulate_until_node,
             current_iterations=current_iterations,
@@ -485,12 +485,6 @@ def dispatch_node(
             self._handle_simulation_notify(simulate_until_node, node)
             return None
 
-        iteration_index = 0
-        parent_nodes = node.get_parent_nodes()
-        if parent_nodes:
-            # Use the normalized iteration index from the context.
-            iteration_index = dispatch_context.current_iterations[parent_nodes[-1].id]
-
         # Return early if this is a simulation as we've reached the
         # simulated node.
         if self._handle_simulation_notify(simulate_until_node, node):
@@ -499,7 +493,7 @@ def dispatch_node(
         history_handler.create_node_result(
             node_history=node_history,
             result=dispatch_result.data,
-            iteration=iteration_index,
+            iteration_path=dispatch_context.get_iteration_path(node),
         )
 
         to_chain = []

backend/src/baserow/contrib/automation/workflows/handler.py

@@ -768,7 +768,7 @@ def toggle_test_run(
                 # This is a placeholder value, no actual history exists yet
                 # (it's created later in start_workflow). This is fine
                 # for now, because get_sample_data() doesn't use history.
-                history_id=0,
+                history=None,
                 simulate_until_node=simulate_until_node,
             )
             if workflow.can_immediately_be_tested() or (