removed branch flow step and fixed predicate validation, added test

rasa/core/policies/flow_policy.py

@@ -65,7 +65,6 @@
     UserMessageStep,
 )
 from rasa.shared.core.flows.steps.link import LinkFlowStep
-from rasa.shared.core.flows.steps.branch import BranchFlowStep
 from rasa.shared.core.flows.steps.action import ActionFlowStep
 from rasa.shared.core.flows.flow import Flow
 from rasa.shared.core.flows.flows_list import FlowsList
@@ -678,10 +677,6 @@ def run_step(
             structlogger.debug("flow.step.run.user_message")
             return ContinueFlowWithNextStep()
 
-        elif isinstance(step, BranchFlowStep):
-            structlogger.debug("flow.step.run.branch")
-            return ContinueFlowWithNextStep()
-
         elif isinstance(step, GenerateResponseFlowStep):
             structlogger.debug("flow.step.run.generate_response")
             generated = step.generate(tracker)
@@ -702,6 +697,10 @@ def run_step(
             reset_events = self._reset_scoped_slots(flow, tracker)
             return ContinueFlowWithNextStep(events=reset_events)
 
+        elif isinstance(step, FlowStep):
+            structlogger.debug("flow.step.run.base_flow_step")
+            return ContinueFlowWithNextStep()
+
         else:
             raise FlowException(f"Unknown flow step type {type(step)}")
 

rasa/shared/core/flows/flow_step.py

@@ -34,7 +34,6 @@ def step_from_json(data: Dict[Text, Any]) -> FlowStep:
         LinkFlowStep,
         SetSlotsFlowStep,
         GenerateResponseFlowStep,
-        BranchFlowStep,
     )
 
     if "action" in data:
@@ -50,7 +49,7 @@ def step_from_json(data: Dict[Text, Any]) -> FlowStep:
     if "generation_prompt" in data:
         return GenerateResponseFlowStep.from_json(data)
     else:
-        return BranchFlowStep.from_json(data)
+        return FlowStep.from_json(data)
 
 
 @dataclass
@@ -69,7 +68,7 @@ class FlowStep:
     """The next steps of the flow step."""
 
     @classmethod
-    def _from_json(cls, flow_step_config: Dict[Text, Any]) -> FlowStep:
+    def from_json(cls, flow_step_config: Dict[Text, Any]) -> FlowStep:
         """Used to read flow steps from parsed YAML.
 
         Args:
@@ -122,7 +121,7 @@ def default_id(self) -> str:
     @property
     def default_id_postfix(self) -> str:
         """Returns the default id postfix of the flow step."""
-        raise NotImplementedError()
+        return "step"
 
     @property
     def utterances(self) -> Set[str]:

rasa/shared/core/flows/steps/__init__.py

@@ -1,5 +1,4 @@
 from .action import ActionFlowStep
-from .branch import BranchFlowStep
 from .collect import CollectInformationFlowStep
 from .continuation import ContinueFlowStep
 from .end import EndFlowStep
@@ -13,7 +12,6 @@
 # to make ruff happy and use the imported names
 all_steps = [
     ActionFlowStep,
-    BranchFlowStep,
     CollectInformationFlowStep,
     ContinueFlowStep,
     EndFlowStep,

rasa/shared/core/flows/steps/action.py

@@ -24,7 +24,7 @@ def from_json(cls, data: Dict[Text, Any]) -> ActionFlowStep:
         Returns:
             An ActionFlowStep object
         """
-        base = super()._from_json(data)
+        base = super().from_json(data)
         return ActionFlowStep(
             action=data["action"],
             **base.__dict__,

rasa/shared/core/flows/steps/collect.py

@@ -67,7 +67,7 @@ def from_json(cls, data: Dict[Text, Any]) -> CollectInformationFlowStep:
         Returns:
             A CollectInformationFlowStep object
         """
-        base = super()._from_json(data)
+        base = super().from_json(data)
         return CollectInformationFlowStep(
             collect=data["collect"],
             utter=data.get("utter", f"utter_ask_{data['collect']}"),

rasa/shared/core/flows/steps/generate_response.py

@@ -38,7 +38,7 @@ def from_json(cls, data: Dict[Text, Any]) -> GenerateResponseFlowStep:
         Returns:
             A GenerateResponseFlowStep object
         """
-        base = super()._from_json(data)
+        base = super().from_json(data)
         return GenerateResponseFlowStep(
             generation_prompt=data["generation_prompt"],
             llm_config=data.get("llm"),

rasa/shared/core/flows/steps/internal.py

@@ -37,3 +37,8 @@ def as_json(self) -> Dict[Text, Any]:
             "Internal flow steps are ephemeral and are not to be serialized "
             "or de-serialized."
         )
+
+    @property
+    def default_id_postfix(self) -> str:
+        """Returns the default id postfix of the flow step."""
+        raise ValueError("Internal flow steps do not need a default id")

rasa/shared/core/flows/steps/link.py

@@ -23,7 +23,7 @@ def from_json(cls, data: Dict[Text, Any]) -> LinkFlowStep:
         Returns:
             a LinkFlowStep object
         """
-        base = super()._from_json(data)
+        base = super().from_json(data)
         return LinkFlowStep(
             link=data.get("link", ""),
             **base.__dict__,

rasa/shared/core/flows/steps/set_slots.py

@@ -23,7 +23,7 @@ def from_json(cls, data: Dict[Text, Any]) -> SetSlotsFlowStep:
         Returns:
             a SetSlotsFlowStep object
         """
-        base = super()._from_json(data)
+        base = super().from_json(data)
         slots = [
             {"key": k, "value": v}
             for slot_sets in data["set_slots"]

rasa/shared/core/flows/steps/user_message.py

@@ -67,7 +67,7 @@ def from_json(cls, flow_step_config: Dict[Text, Any]) -> UserMessageStep:
         Returns:
             The parsed flow step.
         """
-        base = super()._from_json(flow_step_config)
+        base = super().from_json(flow_step_config)
 
         trigger_conditions = []
         if "intent" in flow_step_config:

rasa/validator.py

@@ -10,7 +10,7 @@
 from rasa.shared.core.flows.flow_step_links import IfFlowStepLink
 from rasa.shared.core.flows.steps.set_slots import SetSlotsFlowStep
 from rasa.shared.core.flows.steps.collect import CollectInformationFlowStep
-from rasa.shared.core.flows.steps.branch import BranchFlowStep
+from rasa.shared.core.flows.flow_step import FlowStep
 from rasa.shared.core.flows.steps.action import ActionFlowStep
 from rasa.shared.core.flows.flows_list import FlowsList
 import rasa.shared.nlu.constants
@@ -631,24 +631,23 @@ def _construct_predicate(
         return pred, all_good
 
     def verify_predicates(self) -> bool:
-        """Checks that predicates used in branch flow steps or `collect` steps are valid."""  # noqa: E501
+        """Validate predicates used in flow step links and slot rejections."""
         all_good = True
         for flow in self.flows.underlying_flows:
             for step in flow.steps:
-                if isinstance(step, BranchFlowStep):
-                    for link in step.next.links:
-                        if isinstance(link, IfFlowStepLink):
-                            predicate, all_good = Validator._construct_predicate(
-                                link.condition, step.id
+                for link in step.next.links:
+                    if isinstance(link, IfFlowStepLink):
+                        predicate, all_good = Validator._construct_predicate(
+                            link.condition, step.id
+                        )
+                        if predicate and not predicate.is_valid():
+                            logger.error(
+                                f"Detected invalid condition '{link.condition}' "
+                                f"at step '{step.id}' for flow id '{flow.id}'. "
+                                f"Please make sure that all conditions are valid."
                             )
-                            if predicate and not predicate.is_valid():
-                                logger.error(
-                                    f"Detected invalid condition '{link.condition}' "
-                                    f"at step '{step.id}' for flow id '{flow.id}'. "
-                                    f"Please make sure that all conditions are valid."
-                                )
-                                all_good = False
-                elif isinstance(step, CollectInformationFlowStep):
+                            all_good = False
+                if isinstance(step, CollectInformationFlowStep):
                     predicates = [predicate.if_ for predicate in step.rejections]
                     for predicate in predicates:
                         pred, all_good = Validator._construct_predicate(

tests/test_validator.py

@@ -6,6 +6,10 @@
 import pytest
 from _pytest.logging import LogCaptureFixture
 from rasa.shared.constants import LATEST_TRAINING_DATA_FORMAT_VERSION
+from rasa.shared.core.domain import Domain
+from rasa.shared.core.flows.yaml_flows_io import flows_from_str
+from rasa.shared.core.training_data.structures import StoryGraph
+from rasa.shared.nlu.training_data.training_data import TrainingData
 
 from rasa.validator import Validator
 
@@ -1349,6 +1353,24 @@ def test_verify_predicates_invalid_rejection_if(
     assert error_log in caplog.text
 
 
+def test_flow_predicate_validation_fails_for_faulty_flow_link_predicates():
+    flows = flows_from_str(
+        """
+        flows:
+          pattern_bar:
+            steps:
+            - id: first
+              action: action_listen
+              next:
+                - if: xxx !!!
+                  then: END
+                - else: END
+        """
+    )
+    validator = Validator(Domain.empty(), TrainingData(), StoryGraph([]), flows, None)
+    assert not validator.verify_predicates()
+
+
 @pytest.fixture
 def domain_file_name(tmp_path: Path) -> Path:
     domain_file_name = tmp_path / "domain.yml"