FIX: do not wrap CancelledError into BackendError 🐛

combadge/core/errors.py

@@ -21,7 +21,7 @@ def __exit__(  # type: ignore[misc]
         /,
     ) -> None:
         # Wrapping `CancelledError` breaks `asyncio.TaskGroup`.
-        if exc_value is not None and not isinstance(exc_type, CancelledError):
+        if exc_value is not None and not isinstance(exc_value, CancelledError):
             raise cls(exc_value) from exc_value
 
 

tests/core/test_errors.py

@@ -0,0 +1,17 @@
+from asyncio import CancelledError
+
+import pytest
+
+from combadge.core.errors import BackendError
+
+
+@pytest.mark.parametrize("inner_exception", [ValueError(42)])
+def test_wrapped(inner_exception: BaseException) -> None:
+    with pytest.raises(BackendError), BackendError:
+        raise inner_exception
+
+
+@pytest.mark.parametrize("inner_exception", [CancelledError()])
+def test_non_wrapped(inner_exception: BaseException) -> None:
+    with pytest.raises(type(inner_exception)), BackendError:
+        raise inner_exception