From 0f8bf27b2dc49aa0fb6a39cbea0894b553c3ed0a Mon Sep 17 00:00:00 2001
From: Bernard Knueven <Bernard.Knueven@nrel.gov>
Date: Fri, 17 Feb 2023 11:55:58 -0700
Subject: [PATCH] Revert "switch to nl_v1 (for now)"

This reverts commit f062086c6b229ba5670d42ab23e94e5b6193cf15.
---
 watertap/core/plugins/solvers.py            | 6 ------
 watertap/core/plugins/tests/test_solvers.py | 8 --------
 2 files changed, 14 deletions(-)

diff --git a/watertap/core/plugins/solvers.py b/watertap/core/plugins/solvers.py
index 9a5ece4ec1..aec58a417d 100644
--- a/watertap/core/plugins/solvers.py
+++ b/watertap/core/plugins/solvers.py
@@ -12,7 +12,6 @@
 ###############################################################################
 
 import pyomo.environ as pyo
-from pyomo.opt import WriterFactory
 from pyomo.core.base.block import _BlockData
 from pyomo.core.kernel.block import IBlock
 from pyomo.solvers.plugins.solvers.IPOPT import IPOPT
@@ -26,7 +25,6 @@
 from idaes.logger import getLogger
 
 _log = getLogger("watertap.core")
-_default_nl_writer = WriterFactory.get_class("nl")
 
 
 @pyo.SolverFactory.register(
@@ -57,9 +55,6 @@ def _presolve(self, *args, **kwds):
         if "constr_viol_tol" not in self.options:
             self.options["constr_viol_tol"] = 1e-08
 
-        # temporarily switch to nl_v1 writer
-        WriterFactory.register("nl")(WriterFactory.get_class("nl_v1"))
-
         if not self._is_user_scaling():
             self._cleanup_needed = False
             return super()._presolve(*args, **kwds)
@@ -153,7 +148,6 @@ def _presolve(self, *args, **kwds):
             raise
 
     def _cleanup(self):
-        WriterFactory.register("nl")(_default_nl_writer)
         if self._cleanup_needed:
             self._reset_scaling_factors()
             self._reset_bounds()
diff --git a/watertap/core/plugins/tests/test_solvers.py b/watertap/core/plugins/tests/test_solvers.py
index df15fdfa0d..40a8f1b7d5 100644
--- a/watertap/core/plugins/tests/test_solvers.py
+++ b/watertap/core/plugins/tests/test_solvers.py
@@ -15,7 +15,6 @@
 import pyomo.environ as pyo
 import idaes.core.util.scaling as iscale
 
-from pyomo.opt import WriterFactory
 from pyomo.solvers.plugins.solvers.IPOPT import IPOPT
 from pyomo.common.errors import ApplicationError
 from idaes.core.util.scaling import (
@@ -25,8 +24,6 @@
 from idaes.core.solvers import get_solver
 from watertap.core.plugins.solvers import IpoptWaterTAP
 
-_default_nl_writer = WriterFactory.get_class("nl")
-
 
 class TestIpoptWaterTAP:
     @pytest.fixture(scope="class")
@@ -64,11 +61,6 @@ def _test_bounds(self, m):
     def s(self):
         return pyo.SolverFactory("ipopt-watertap")
 
-    @pytest.mark.unit
-    def test_nl_writer_held_harmless(self, m, s):
-        s.solve(m, tee=True)
-        assert _default_nl_writer == WriterFactory.get_class("nl")
-
     @pytest.mark.unit
     def test_pyomo_registration(self, s):
         assert s.__class__ is IpoptWaterTAP