Clear internal caches when re-creating from same SMIRNOFF objects

openff/interchange/components/interchange.py

@@ -158,8 +158,6 @@ def from_smirnoff(
         """
         from openff.interchange.smirnoff._create import _create_interchange
 
-        _clear_caches()
-
         return _create_interchange(
             force_field=force_field,
             topology=topology,
@@ -845,8 +843,6 @@ def from_foyer(
         """
         from openff.interchange.foyer._create import _create_interchange
 
-        _clear_caches()
-
         return _create_interchange(
             force_field=force_field,
             topology=topology,
@@ -1108,15 +1104,3 @@ def __repr__(self) -> str:
             f"Interchange with {len(self.collections)} collections, "
             f"{'' if periodic else 'non-'}periodic topology with {n_atoms} atoms."
         )
-
-
-def _clear_caches():
-    import functools
-    import gc
-
-    for obj in gc.get_objects():
-        try:
-            if isinstance(obj, functools._lru_cache_wrapper) and obj.__module__.startswith("openff.interchange"):
-                obj.cache_clear()
-        except ReferenceError:
-            continue

openff/interchange/components/potentials.py

@@ -3,8 +3,6 @@
 from __future__ import annotations
 
 import ast
-import functools
-import gc
 import json
 from typing import TYPE_CHECKING, Annotated, Any, TypeAlias
 
@@ -291,13 +289,6 @@ def get_force_field_parameters(
     def set_force_field_parameters(self, new_p: ArrayLike) -> None:
         """Set the force field parameters from a flattened representation."""
 
-        # Clear cache of all methods that are wrapped by functools.lru_cache
-        # A better solution might be at the level of parameter re-assignment
-        # See issue #1234
-        for obj in gc.get_objects():
-            if isinstance(obj, functools._lru_cache_wrapper) and obj.__module__.startswith("openff.interchange"):
-                obj.cache_clear()
-
         mapping = self.get_mapping()
         if new_p.shape[0] != len(mapping):  # type: ignore
             raise RuntimeError

openff/interchange/smirnoff/_create.py

@@ -134,6 +134,24 @@ def _preprocess_preset_charges(
     return molecules_with_preset_charges
 
 
+def _clear_smirnoff_creation_caches():
+    """
+    Due to bugs in the toolkit, these caches can be invalid of a force field is modified and then
+    sent to (SMIRNOFF) creation pathways again. This function clears those caches - call it whenever
+    `Interchange.from_smirnoff` may be called multiple times on the same force field object
+    (including possible modifications).
+
+    https://github.com/openforcefield/openff-toolkit/issues/2065
+    """
+    from openff.interchange.components.toolkit import _cache_angle_parameter_lookup, _cache_torsion_parameter_lookup
+
+    for obj in [
+        _cache_angle_parameter_lookup,
+        _cache_torsion_parameter_lookup,
+    ]:
+        obj.cache_clear()
+
+
 def _create_interchange(
     force_field: ForceField,
     topology: Topology | list[Molecule],
@@ -147,6 +165,8 @@ def _create_interchange(
 
     _check_supported_handlers(force_field)
 
+    _clear_smirnoff_creation_caches()
+
     if molecules_with_preset_charges and "VirtualSites" in force_field.registered_parameter_handlers:
         warnings.warn(
             "Preset charges were provided (via `charge_from_molecules`) alongside a force field that includes "