fix hirerchey

Author: omereliy

CHANGELOG.md

@@ -6,6 +6,21 @@ Format: [Keep a Changelog](https://keepachangelog.com/en/1.1.0/). Versioning: [S
 
 ## [Unreleased]
 
+## [0.1.2] — 2026-04-11
+
+### Fixed
+- Plan structure validation now honors PDDL type hierarchies. Objects whose
+  type is a transitive subtype of an action parameter's declared type are
+  accepted (e.g., an object typed `depot` satisfies a `place` parameter when
+  the domain declares `depot - place`). Previously the `is_compatible` check
+  was called with swapped arguments, rejecting every typed IPC benchmark
+  (depots, driverlog, rovers, ...) at the structure phase.
+
+### Added
+- Regression tests (`tests/test_validator.py`) with a small `vhcl` domain
+  exercising both positive (subtype accepted) and negative (sibling branch
+  rejected) cases, plus matching fixtures in `tests/conftest.py`.
+
 ## [0.1.1] — 2026-04-09
 
 ### Added

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "pddl-pyvalidator"
-version = "0.1.1"
+version = "0.1.2"
 description = "Pure Python PDDL plan validator"
 license = "MIT"
 requires-python = ">=3.10"

pyval/__init__.py

@@ -1,6 +1,6 @@
 """PyVAL — Pure Python PDDL plan validator."""
 
-__version__ = "0.1.1"
+__version__ = "0.1.2"
 
 from pyval.models import (
     GoalResult,

pyval/validator.py

@@ -170,7 +170,10 @@ def _validate_plan_structure(
             original_names[obj.name] = param_name_raw
 
             expected_type = action_schema.parameters[i].type
-            if not obj.type.is_compatible(expected_type):
+            # `Type.is_compatible(self, other)` returns True iff an object of
+            # type `other` can be assigned to a slot of type `self`. The
+            # parameter type is the target, so it must be on the left.
+            if not expected_type.is_compatible(obj.type):
                 errors.append(
                     f"Step {step_idx}: Action '{action_name_raw}' — "
                     f"parameter {i + 1} expects type '{expected_type}', "

tests/conftest.py

@@ -171,6 +171,60 @@
 """
 
 
+# ---------------------------------------------------------------------------
+# Typed hierarchy: vehicles + cargo (for subtype compatibility checks)
+# ---------------------------------------------------------------------------
+
+TYPED_HIERARCHY_DOMAIN = """\
+(define (domain vhcl)
+  (:requirements :strips :typing)
+  (:types
+    vehicle cargo - object
+    truck plane - vehicle)
+  (:predicates
+    (parked ?v - vehicle)
+    (stored ?c - cargo)
+  )
+
+  (:action start
+    :parameters (?v - vehicle)
+    :precondition (parked ?v)
+    :effect (not (parked ?v))
+  )
+)
+"""
+
+TYPED_HIERARCHY_PROBLEM = """\
+(define (problem vhcl-p1)
+  (:domain vhcl)
+  (:objects
+    truck1 - truck
+    plane1 - plane
+    box1 - cargo
+  )
+  (:init
+    (parked truck1)
+    (parked plane1)
+    (stored box1)
+  )
+  (:goal (and (not (parked truck1)) (not (parked plane1))))
+)
+"""
+
+# Subtype plan: (start truck1) passes a `truck` where `vehicle` is expected.
+# Must be accepted — PDDL typing is hierarchical.
+TYPED_HIERARCHY_SUBTYPE_PLAN = """\
+(start truck1)
+(start plane1)
+"""
+
+# Sibling-branch plan: (start box1) passes a `cargo` where `vehicle` is
+# expected. Must be rejected — cargo is not in vehicle's subtree.
+TYPED_HIERARCHY_SIBLING_PLAN = """\
+(start box1)
+"""
+
+
 # ---------------------------------------------------------------------------
 # Helpers
 # ---------------------------------------------------------------------------

tests/test_validator.py

@@ -6,6 +6,10 @@
     BLOCKSWORLD_VALID_PLAN,
     LOGISTICS_FUEL_DOMAIN,
     LOGISTICS_FUEL_PROBLEM,
+    TYPED_HIERARCHY_DOMAIN,
+    TYPED_HIERARCHY_PROBLEM,
+    TYPED_HIERARCHY_SIBLING_PLAN,
+    TYPED_HIERARCHY_SUBTYPE_PLAN,
     write_pddl_files,
 )
 
@@ -86,6 +90,39 @@ def test_empty_plan(tmp_path):
     assert result.phases["structure"]["status"] == "PASS"
 
 
+def test_subtype_object_accepted_for_supertype_parameter(tmp_path):
+    """Action parameter typed `vehicle` must accept a `truck` (subtype)."""
+    paths = write_pddl_files(
+        tmp_path,
+        TYPED_HIERARCHY_DOMAIN,
+        TYPED_HIERARCHY_PROBLEM,
+        TYPED_HIERARCHY_SUBTYPE_PLAN,
+    )
+    v = PDDLValidator()
+    result = v.validate(paths["domain"], paths["problem"], paths["plan"])
+    assert result.phases["structure"]["status"] == "PASS", (
+        result.phases["structure"]["errors"]
+    )
+
+
+def test_sibling_type_rejected_for_parameter(tmp_path):
+    """An object from a sibling branch (cargo) must NOT satisfy a vehicle parameter."""
+    paths = write_pddl_files(
+        tmp_path,
+        TYPED_HIERARCHY_DOMAIN,
+        TYPED_HIERARCHY_PROBLEM,
+        TYPED_HIERARCHY_SIBLING_PLAN,
+    )
+    v = PDDLValidator()
+    result = v.validate(paths["domain"], paths["problem"], paths["plan"])
+    assert not result.is_valid
+    assert result.status == "STRUCTURE_ERROR"
+    assert any(
+        "expects type 'vehicle'" in e and "box1" in e
+        for e in result.phases["structure"]["errors"]
+    )
+
+
 def test_comment_and_cost_lines_skipped(tmp_path):
     plan = """\
 ; This is a comment