feat: add poster method that raises an exception (#1038)

Co-authored-by: Mohamed Koubaa <[email protected]>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: pyansys-ci-bot <[email protected]>

doc/changelog.d/1038.added.md

@@ -0,0 +1 @@
+add poster method that raises an exception

src/ansys/mechanical/core/embedding/poster.py

@@ -25,6 +25,19 @@
 import typing
 
 
+class PosterError(Exception):
+    """Class which holds errors from the background thread posting system."""
+
+    def __init__(self, error: Exception):
+        """Create an instance to hold the given error."""
+        self._error = error
+
+    @property
+    def error(self) -> Exception:
+        """Get the underlying exception."""
+        return self._error
+
+
 class Poster:
     """Class which can post a python callable function to Mechanical's main thread."""
 
@@ -37,7 +50,26 @@ def __init__(self):
 
         self._poster = Ans.Common.WB1ManagedUtils.TaskPoster
 
-    def post(self, callable: typing.Callable):
+    def try_post(self, callable: typing.Callable) -> typing.Any:
+        """Post the callable to Mechanical's main thread.
+
+        This does the same thing as `post` but if `callable`
+        raises an exception, try_post will raise the same
+        exception to the caller of `try_post`.
+        """
+
+        def wrapped():
+            try:
+                return callable()
+            except Exception as e:
+                return PosterError(e)
+
+        result = self.post(wrapped)
+        if isinstance(result, PosterError):
+            raise result.error
+        return result
+
+    def post(self, callable: typing.Callable) -> typing.Any:
         """Post the callable to Mechanical's main thread.
 
         The main thread needs to be receiving posted messages

tests/embedding/test_app.py

@@ -169,6 +169,7 @@ def test_app_poster(embedded_app):
     poster = embedded_app.poster
 
     name = []
+    error = []
 
     def change_name_async(poster):
         """Change_name_async will run a background thread
@@ -182,9 +183,19 @@ def get_name():
         def change_name():
             embedded_app.DataModel.Project.Name = "foo"
 
+        def raise_ex():
+            raise Exception("Exception")
+
         name.append(poster.post(get_name))
         poster.post(change_name)
 
+        try:
+            poster.try_post()
+        except Exception as e:
+            error.append(e)
+
+        name.append(poster.try_post(get_name))
+
     import threading
 
     change_name_thread = threading.Thread(target=change_name_async, args=(poster,))
@@ -196,9 +207,11 @@ def change_name():
     # thread, e.g. `change_name` that was posted by the poster.
     utils.sleep(400)
     change_name_thread.join()
-    assert len(name) == 1
+    assert len(name) == 2
     assert name[0] == "Project"
+    assert name[1] == "foo"
     assert embedded_app.DataModel.Project.Name == "foo"
+    assert len(error) == 1
 
 
 @pytest.mark.embedding