feat: server error handling more robust

Author: Redansys

src/ansys/dpf/gate/errors.py

@@ -1,16 +1,25 @@
 import types
+import sys
 from functools import wraps
 
 class DPFServerException(Exception):
     """Error raised when the DPF server has encountered an error."""
 
     def __init__(self, msg=""):
-        parts = msg.rsplit('<-', maxsplit=1)
-        error_message = parts[1]
-        error_note = parts[0]
+        message_parts = msg.rsplit('<-', maxsplit=1)
+        error_note = ""
+        if len(message_parts) == 1:
+            error_message = message_parts[0]
+        else:
+            error_note, error_message = message_parts
 
         Exception.__init__(self, error_message)
-        self.add_note(error_note)
+        if sys.version_info >= (3, 11): #add_note method is supported only in python >= 3.11
+            self.add_note(error_note)
+        else:
+            if not hasattr(self, "__notes__"): #if the system is python < 3.11 we custom our own notes property
+                self.__notes__ = []
+            self.__notes__.append(error_note)
 
 
 class DPFServerNullObject(Exception):

tests/test_server_errors.py

@@ -0,0 +1,45 @@
+# Copyright (C) 2020 - 2025 ANSYS, Inc. and/or its affiliates.
+# 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.
+
+import pytest
+import sys
+
+from ansys import dpf
+from ansys.dpf.core import errors, operators as ops
+
+def test_server_exception_from_operator():
+    ds = dpf.core.DataSources(r"dummy/file.rst")
+    op = ops.result.displacement(data_sources=ds)
+    with pytest.raises(errors.DPFServerException) as exception_note:
+        op.eval()
+
+    assert hasattr(exception_note, '__notes__'), "The exception does not contain any note"
+    assert exception_note.__notes__
+
+def test_server_exception_from_workflow():
+  disp = ops.result.displacement()
+  workflow = dpf.Workflow()
+
+  workflow.add_operator(disp)
+  workflow.set_output_name("displacement", disp.outputs.fields_container)
+  workflow.eval()
+