Fix incorrect assignment of TIP3P parameters in Sage (#1200) (#1220)

* Add test for TIP3P charges with Sage

* Do not uniquify SMARTS in LibraryChargeHandler

* Also test standalone TIP3P file

* Consolidate tip3p charge tests

* black

* Update release history

Co-authored-by: j-wags <jwagnerjpl@gmail.com>

Co-authored-by: j-wags <jwagnerjpl@gmail.com>

docs/releasehistory.md

@@ -78,6 +78,17 @@ print(value_roundtrip)
 - [PR #1213](https://github.com/openforcefield/openff-toolkit/pull/1213): Removes
   `Topology.charge_model` and `Topology.fractional_bond_order_model`.
 
+### Critical bugfixes
+
+- [PR #1200](https://github.com/openforcefield/openforcefield/pull/1200): Fixes a bug
+  ([Issue #1199](https://github.com/openforcefield/openff-toolkit/issues/428)) in which library
+  charges were ignored in some force fields, including `openff-2.0.0` code name "Sage." This resulted in
+  the TIP3P partial charges included Sage not being applied correctly in versions 0.10.1 and 0.10.2 of the
+  OpenFF Toolkit. This regression was not present in version 0.10.0 and earlier and therefore is not
+  believed to have any impact on the fitting or benchmarking of the first release of Sage (version
+  2.0.0). The change causing regression only affected library charges and therefore no other
+  parameter types are believed to be affected.
+
 ### Behaviors changed and bugfixes
 
 - [PR #1182](https://github.com/openforcefield/openforcefield/pull/1182) and

openff/toolkit/tests/test_forcefield.py

@@ -2430,11 +2430,19 @@ def test_some_charges_from_molecule(self, toolkit_registry, registry_description
             q, sigma, epsilon = nonbondedForce.getParticleParameters(particle_index)
             assert q != (0.0 * unit.elementary_charge)
 
-    def test_library_charges_to_single_water(self):
+    @pytest.mark.parametrize(
+        "ff_inputs",
+        [
+            [
+                "test_forcefields/test_forcefield.offxml",
+                "test_forcefields/tip3p.offxml",
+            ],
+            ["openff-2.0.0.offxml"],
+        ],
+    )
+    def test_library_charges_to_single_water(self, ff_inputs):
         """Test assigning charges to one water molecule using library charges"""
-        ff = ForceField(
-            "test_forcefields/test_forcefield.offxml", "test_forcefields/tip3p.offxml"
-        )
+        ff = ForceField(*ff_inputs)
         mol = Molecule.from_file(
             get_data_file_path(os.path.join("systems", "monomers", "water.sdf"))
         )

openff/toolkit/typing/engines/smirnoff/parameters.py

@@ -4059,7 +4059,7 @@ def from_molecule(cls, molecule):
     _INFOTYPE = LibraryChargeType  # info type to store
     _DEPENDENCIES = [vdWHandler, ElectrostaticsHandler]
 
-    def find_matches(self, entity, unique=True):
+    def find_matches(self, entity, unique=False):
         """Find the elements of the topology/molecule matched by a parameter type.
 
         Parameters