From 41c022791c0dfb382c28346b3bc228096e54d6d6 Mon Sep 17 00:00:00 2001
From: Montana <montana@linux.com>
Date: Fri, 18 Sep 2026 08:09:51 -0700
Subject: [PATCH] fix(bindings): prevent empty-model dereference in Janus
 representation

---
 Python/src/pyJanus.cpp                    |  8 ++---
 Python/tests/test_janus_representation.py | 39 +++++++++++++++++++++++
 2 files changed, 43 insertions(+), 4 deletions(-)
 create mode 100644 Python/tests/test_janus_representation.py

diff --git a/Python/src/pyJanus.cpp b/Python/src/pyJanus.cpp
index 4310d6c..947067f 100644
--- a/Python/src/pyJanus.cpp
+++ b/Python/src/pyJanus.cpp
@@ -51,19 +51,19 @@ void init_Janus(py::module_ &m)
       .def_property_readonly("xml_filename", &Janus::getXmlFileName)
 
       .def("__repr__",
-           [](Janus &self)
+           [](const Janus &self)
            {
              std::ostringstream out;
-             out << "Janus(xml_filename='" << self.getXmlFileName() << ")"
+             out << "Janus(xml_filename='" << self.getXmlFileName() << "')"
                  << " at JanusInstance<"
-                 << self.getVariableDef().front().getJanusInstance() << ">";
+                 << &self << ">";
              return out.str();
            })
       .def("__str__",
            [](const Janus &self)
            {
              std::ostringstream out;
-             out << "Janus(xml_filename='" << self.getXmlFileName() << ")";
+             out << "Janus(xml_filename='" << self.getXmlFileName() << "')";
              return out.str();
            });
 }
diff --git a/Python/tests/test_janus_representation.py b/Python/tests/test_janus_representation.py
new file mode 100644
index 0000000..8a37ed7
--- /dev/null
+++ b/Python/tests/test_janus_representation.py
@@ -0,0 +1,39 @@
+import os
+import re
+import subprocess
+import sys
+
+import pyJanus
+
+
+def test_empty_janus_repr():
+    # Isolate the call so a native crash is reported as a test failure instead
+    # of terminating the entire test suite.
+    result = subprocess.run(
+        [sys.executable, "-c", "import pyJanus; print(repr(pyJanus.Janus()))"],
+        capture_output=True,
+        text=True,
+        timeout=30,
+    )
+
+    assert result.returncode == 0, result.stderr
+    assert re.fullmatch(
+        r"Janus\(xml_filename=''\) at JanusInstance<[^<>\s]+>\n",
+        result.stdout,
+    )
+
+
+def test_empty_janus_str():
+    text = str(pyJanus.Janus())
+    assert text == "Janus(xml_filename='')"
+
+
+def test_loaded_janus_representation():
+    xml_path = f"{os.path.dirname(__file__)}/../../Examples/CombinedExample.xml"
+    janus = pyJanus.Janus(xml_path)
+    expected = f"Janus(xml_filename='{janus.xml_filename}')"
+    variable = janus.get_variabledef("angleOfAttack")
+    instance = repr(variable).split(" from ", 1)[1]
+
+    assert str(janus) == expected
+    assert repr(janus) == f"{expected} at {instance}"