Related: #53395

providers/microsoft/azure/src/airflow/providers/microsoft/azure/secrets/key_vault.py:106: error: Statement is unreachable [unreachable]
self.connections_prefix = connections_prefix

providers/microsoft/azure/src/airflow/providers/microsoft/azure/secrets/key_vault.py:110: error: Statement is unreachable [unreachable]
self.variables_prefix = variables_prefix

providers/microsoft/azure/src/airflow/providers/microsoft/azure/secrets/key_vault.py:114: error: Statement is unreachable [unreachable]
self.config_prefix = config_prefix

providers/microsoft/azure/src/airflow/providers/microsoft/azure/secrets/key_vault.py:151: error: Statement is unreachable [unreachable]
return None

providers/microsoft/azure/src/airflow/providers/microsoft/azure/secrets/key_vault.py:163: error: Statement is unreachable [unreachable]
return None

providers/microsoft/azure/src/airflow/providers/microsoft/azure/secrets/key_vault.py:175: error: Statement is unreachable [unreachable]
return None

All of the variables (connections_prefix, variables_prefix, config_prefix) are allowed to be None, as seen in existing test cases. However, the original code only implied string types, leading to unreachable MyPy errors.

We resolved this by:
• Explicitly annotating input arguments as str | None
• Using safe conditional initialization with

original:

if connections_prefix:
    self.connections_prefix = connections_prefix.rstrip(sep)
else:
    self.connections_prefix = connections_prefix

self.connections_prefix = connections_prefix
if isinstance(self.connections_prefix, str):
    self.connections_prefix.rstrip(sep)

providers/microsoft/azure/src/airflow/providers/microsoft/azure/hooks/wasb.py:599: error: Statement is unreachable [unreachable]
conn = await sync_to_async(self.get_connection)(self.conn_id)

The code was flagged as unreachable by MyPy because self.blob_service_client was not annotated to allow None.
As a result, the following condition is always True from the type checker’s perspective:

if self.blob_service_client is not None:
    return self.blob_service_client

To fix this, we explicitly annotated the attribute to allow None:

self.blob_service_client: AsyncBlobServiceClient | None = None  # type: ignore

This makes the conditional logic valid and resolves the MyPy warning.

providers/microsoft/azure/src/airflow/providers/microsoft/azure/hooks/msgraph.py:463: error: Statement is unreachable [unreachable]
request_information.content = data

Added bytes to the input type annotation to fix a type mismatch.

providers/microsoft/azure/src/airflow/providers/microsoft/azure/operators/synapse.py:129: error: Statement is unreachable [unreachable]
self.hook.cancel_job_run(

Annotated self.job_id as Any to match its default value None and resolve the type warning.

providers/microsoft/azure/src/airflow/providers/microsoft/azure/operators/msgraph.py:260: error: Statement is unreachable [unreachable]
if append_result_as_list_if_absent:

The is condition was unreachable due to the static type of results. Changing its annotation to Any resolves the issue.