Improve exception for humans (#208)

CHANGES.rst

@@ -1,6 +1,14 @@
 Changelog
 =========
 
+1.3.0
+-----
+
+Features
+~~~~~~~~
+- Support ``InvalidObjectNameError`` in ``sqlalchemy_hana.errors``
+- Add ``convert_dbapi_error`` to ``sqlalchemy_hana.errors``
+
 1.2.0
 -----
 

pyproject.toml

@@ -123,6 +123,7 @@ disable = [
     "too-many-public-methods",
     "too-many-function-args",
     "too-many-lines",
+    "too-many-branches",
 ]
 
 [tool.pylint.basic]

sqlalchemy_hana/errors.py

@@ -59,6 +59,10 @@ class TransactionCancelledError(HANAError):
     """Error raised when a transaction is cancelled."""
 
 
+class InvalidObjectNameError(HANAError):
+    """Error when an invalid object name is referenced."""
+
+
 def wrap_dbapi_error(error: DBAPIError) -> None:
     """Takes a :py:exc:`sqlalchemy.exc.DBAPIError` and raises a more specific exception if possible.
 
@@ -77,6 +81,19 @@ def wrap_dbapi_error(error: DBAPIError) -> None:
         wrap_hdbcli_error(error.orig)
 
 
+def convert_dbapi_error(error: DBAPIError) -> DBAPIError | HANAError:
+    """Takes a :py:exc:`sqlalchemy.exc.DBAPIError` and converts it to a more specific exception.
+
+    Similar to :py:func:`~wrap_dbapi_error`, but instead of throwing the error, it returns it as
+    an object.
+    """
+    try:
+        wrap_dbapi_error(error)
+    except HANAError as thrown:
+        return thrown
+    return error
+
+
 def wrap_hdbcli_error(error: HdbcliError) -> None:
     """Wraps the given :py:exc:`hdbcli.dbapi.Error` and raises specific exception if possible.
 
@@ -151,6 +168,8 @@ def wrap_hdbcli_error(error: HdbcliError) -> None:
         and "An error occurred while opening the channel" in error.errortext
     ):
         raise StatementExecutionError from error
+    if error.errorcode == 397:
+        raise InvalidObjectNameError from error
 
 
 __all__ = (
@@ -166,4 +185,6 @@ def wrap_hdbcli_error(error: HdbcliError) -> None:
     "DeadlockError",
     "DatabaseOverloadedError",
     "StatementExecutionError",
+    "InvalidObjectNameError",
+    "convert_dbapi_error",
 )

test/test_errors.py

@@ -15,12 +15,14 @@
     DatabaseOutOfMemoryError,
     DatabaseOverloadedError,
     DeadlockError,
+    InvalidObjectNameError,
     LockAcquisitionError,
     LockWaitTimeoutError,
     SequenceCacheTimeoutError,
     StatementExecutionError,
     StatementTimeoutError,
     TransactionCancelledError,
+    convert_dbapi_error,
     wrap_dbapi_error,
     wrap_hdbcli_error,
 )
@@ -96,6 +98,7 @@ def test_wrap_hdbcli_error_txsavepoint_not_found(self) -> None:
                 TransactionCancelledError,
             ),
             (613, "", StatementTimeoutError),
+            (397, "", InvalidObjectNameError),
         ],
     )
     def test_wrap_hdbcli_error(
@@ -120,3 +123,26 @@ def test_wrap_hdbcli_error(
     def test_wrap_hdbcli_error_no_wrap(self, errorcode: int, errortext: str) -> None:
         error = HdbcliError(errorcode, errortext)
         wrap_hdbcli_error(error)
+
+
+class TestConvertDbapiError(TestBase):
+    def test_calls_wrap_dbapi_error_throw(self) -> None:
+        error = DBAPIError("", None, orig=HdbcliError())
+
+        with mock.patch(
+            "sqlalchemy_hana.errors.wrap_dbapi_error", side_effect=StatementTimeoutError
+        ) as mocked:
+            new_error = convert_dbapi_error(error)
+            assert isinstance(new_error, StatementTimeoutError)
+
+        mocked.assert_called_once_with(error)
+
+    def test_calls_not_wrap_hdbcli_error_no_throw(self) -> None:
+        error = DBAPIError("", None, orig=ValueError())
+
+        with mock.patch(
+            "sqlalchemy_hana.errors.wrap_dbapi_error", return_value=None
+        ) as mocked:
+            assert convert_dbapi_error(error) == error
+
+        mocked.assert_called_once_with(error)