From 13abc2408199df81589b262685fd0a2eecee6c6f Mon Sep 17 00:00:00 2001
From: "Josef M. Gallmetzer" <64498081+galjos@users.noreply.github.com>
Date: Wed, 2 Sep 2026 14:52:10 +0200
Subject: [PATCH] fix: reject mm-opt with MD ensembles

mm-opt is an optimization job type. Pairing it with NVT/NVE/NPT used to validate and export fake MD input.
---
 pqsetup/input_writer.py         | 10 ++++++++++
 tests/test_presets_and_input.py | 14 ++++++++++++++
 2 files changed, 24 insertions(+)

diff --git a/pqsetup/input_writer.py b/pqsetup/input_writer.py
index 7f7406d..99b10b9 100644
--- a/pqsetup/input_writer.py
+++ b/pqsetup/input_writer.py
@@ -256,6 +256,16 @@ def validate_setup(
                 ),
             )
         )
+    if setup.job_type == "mm-opt" and setup.ensemble != "OPT":
+        diagnostics.append(
+            _error(
+                "workflow.mm_opt_ensemble",
+                (
+                    "mm-opt is an optimization job type and cannot use an "
+                    "MD ensemble."
+                ),
+            )
+        )
     if not setup.start_file:
         diagnostics.append(_error("input.start_file", "Start file is required."))
     if not setup.file_prefix:
diff --git a/tests/test_presets_and_input.py b/tests/test_presets_and_input.py
index 9863a69..20b8532 100644
--- a/tests/test_presets_and_input.py
+++ b/tests/test_presets_and_input.py
@@ -73,6 +73,20 @@ def test_incomplete_mm_optimization_package_is_rejected() -> None:
     assert {item.code for item in result.diagnostics} == {"workflow.unsupported"}
 
 
+def test_mm_opt_with_md_ensemble_is_rejected() -> None:
+    result = render_input(
+        SimulationSetup(
+            job_type="mm-opt",
+            ensemble="NVT",
+            thermostat="berendsen",
+            runner=None,
+        )
+    )
+
+    assert not result.valid
+    assert "workflow.mm_opt_ensemble" in {item.code for item in result.diagnostics}
+
+
 def test_unreleased_and_unknown_runners_fail_without_probing(
     monkeypatch,
 ) -> None: