Fix AttributeError masking dropped AEDT connection in solution_type fallback

src/ansys/aedt/core/application/design_solutions.py

@@ -86,14 +86,14 @@ def solution_type(self, value: str) -> None:
                 DesignType.EMIT,
                 DesignType.Q3D,
             ]:
-                self._solution_type = self._design_type.default_solution
+                self._solution_type = self._design_type.solution_default
             elif self._odesign:
                 try:
                     self._solution_type = self._odesign.GetSolutionType()
                 except Exception:
-                    self._solution_type = self._design_type.default_solution
+                    self._solution_type = self._design_type.solution_default
             else:
-                self._solution_type = self._design_type.default_solution
+                self._solution_type = self._design_type.solution_default
         elif value and value in self._solution_options:
             self._solution_type = value
             if self._solution_options[value]["name"]:
@@ -215,9 +215,9 @@ def solution_type(self) -> str:
                 elif "Terminal" in self._solution_type:
                     self._solution_type = "Terminal"
             except Exception:
-                self._solution_type = self._design_type.default_solution
+                self._solution_type = self._design_type.solution_default
         elif self._solution_type is None:
-            self._solution_type = self._design_type.default_solution
+            self._solution_type = self._design_type.solution_default
         return self._solution_type
 
     @solution_type.setter
@@ -246,9 +246,9 @@ def solution_type(self, value: str) -> None:
                     elif "Terminal" in self._solution_type:
                         self._solution_type = "Terminal"
                 except Exception:
-                    self._solution_type = self._design_type.default_solution
+                    self._solution_type = self._design_type.solution_default
             else:
-                self._solution_type = self._design_type.default_solution
+                self._solution_type = self._design_type.solution_default
         elif value and value in self._solution_options and self._solution_options[value]["name"]:
             if value == "Transient" or value == "Transient Network":
                 value = "Transient Network"
@@ -415,7 +415,7 @@ def solution_type(self):
             try:
                 self._solution_type = self._odesign.GetSolutionType()
             except Exception:
-                self._solution_type = self._design_type.default_solution
+                self._solution_type = self._design_type.solution_default
         return self._solution_type
 
     @solution_type.setter
@@ -515,7 +515,7 @@ def solution_type(self) -> str:
             try:
                 self._solution_type = self._odesign.GetSolutionType()
             except Exception:
-                self._solution_type = self._design_type.default_solution
+                self._solution_type = self._design_type.solution_default
         return self._solution_type
 
     @solution_type.setter

tests/unit/test_design_solutions.py

@@ -0,0 +1,103 @@
+# -*- coding: utf-8 -*-
+#
+# Copyright (C) 2021 - 2026 Synopsys, Inc. and ANSYS, Inc. All rights reserved.
+# SPDX-License-Identifier: MIT
+#
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in all
+# copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+
+
+from ansys.aedt.core.application.design_solutions import DesignSolution
+from ansys.aedt.core.application.design_solutions import HFSSDesignSolution
+from ansys.aedt.core.generic.aedt_constants import HfssConstants
+from ansys.aedt.core.generic.aedt_constants import Q3dConstants
+
+
+class RaisingODesign:
+    """Stand-in for a design whose gRPC connection to AEDT has dropped.
+
+    ``GetSolutionType()`` raising mirrors what happens when the connection
+    to AEDT is lost: the ``except Exception`` fallback in
+    ``design_solutions.py`` is exercised.
+    """
+
+    def GetSolutionType(self):
+        raise RuntimeError("connection lost")
+
+
+def test_constants_only_define_solution_default():
+    """The constant classes only ever define ``solution_default``."""
+    assert hasattr(HfssConstants, "solution_default")
+    assert not hasattr(HfssConstants, "default_solution")
+    assert hasattr(Q3dConstants, "solution_default")
+    assert not hasattr(Q3dConstants, "default_solution")
+
+
+def test_design_solution_getter_falls_back_on_connection_error():
+    """DesignSolution.solution_type getter should not raise on a dropped connection."""
+    ds = DesignSolution.__new__(DesignSolution)
+    ds._odesign = RaisingODesign()
+    ds._design_type = HfssConstants
+    ds._solution_type = None
+
+    assert ds.solution_type == HfssConstants.solution_default
+
+
+def test_design_solution_setter_falls_back_on_connection_error():
+    """DesignSolution.solution_type setter (value=None) should not raise on a dropped connection.
+
+    Regression test for the bug where the fallback read
+    ``self._design_type.default_solution`` instead of ``solution_default``,
+    turning a lost-connection error into a confusing AttributeError.
+    """
+    ds = DesignSolution.__new__(DesignSolution)
+    ds._odesign = RaisingODesign()
+    ds._design_type = HfssConstants
+    ds._solution_type = None
+    ds._solution_options = {
+        "Modal": {"name": "HFSS Modal Network", "options": None},
+        "Terminal": {"name": "HFSS Terminal Network", "options": None},
+    }
+
+    ds.solution_type = None
+
+    assert ds._solution_type == HfssConstants.solution_default
+
+
+def test_design_solution_setter_no_odesign_falls_back():
+    """DesignSolution.solution_type setter with no attached design still falls back correctly."""
+    ds = DesignSolution.__new__(DesignSolution)
+    ds._odesign = None
+    ds._design_type = Q3dConstants
+    ds._solution_type = None
+    ds._solution_options = {}
+
+    ds.solution_type = None
+
+    assert ds._solution_type == Q3dConstants.solution_default
+
+
+def test_hfss_design_solution_getter_falls_back_on_connection_error():
+    """HFSSDesignSolution.solution_type getter should not raise on a dropped connection."""
+    hds = HFSSDesignSolution.__new__(HFSSDesignSolution)
+    hds._odesign = RaisingODesign()
+    hds._design_type = HfssConstants
+    hds._solution_type = None
+
+    assert hds.solution_type == HfssConstants.solution_default