Cleanup type ignores in mysql provider where possible (#53288)

* Cleanup type ignores in mysql provider where possible

* Revert two type ignore cleanups as long as imports with task sdk inconsistent

* Fix typing error and handling of undefined unicode

* Uuups

Co-authored-by: GPK <[email protected]>

* Fix typing errors next round

* Fix typing errors next round, v2

---------

Co-authored-by: GPK <[email protected]>

Author: jscheffl

providers/mysql/src/airflow/providers/mysql/hooks/mysql.py

@@ -30,7 +30,12 @@
 logger = logging.getLogger(__name__)
 
 if TYPE_CHECKING:
-    from airflow.models import Connection
+    from airflow.providers.mysql.version_compat import AIRFLOW_V_3_0_PLUS
+
+    if AIRFLOW_V_3_0_PLUS:
+        from airflow.sdk import Connection
+    else:
+        from airflow.models.connection import Connection  # type: ignore[assignment]
 
     try:
         from mysql.connector.abstracts import MySQLConnectionAbstract
@@ -130,7 +135,7 @@ def _get_conn_config_mysql_client(self, conn: Connection) -> dict:
 
         if conn.extra_dejson.get("charset", False):
             conn_config["charset"] = conn.extra_dejson["charset"]
-            if conn_config["charset"].lower() in ("utf8", "utf-8"):
+            if str(conn_config.get("charset", "undef")).lower() in ("utf8", "utf-8"):
                 conn_config["use_unicode"] = True
         if conn.extra_dejson.get("cursor", False):
             try:
@@ -220,7 +225,7 @@ def get_conn(self) -> MySQLConnectionTypes:
                     "installed in case you see compilation error during installation."
                 )
 
-            conn_config = self._get_conn_config_mysql_client(conn)  # type: ignore[arg-type]
+            conn_config = self._get_conn_config_mysql_client(conn)
             return MySQLdb.connect(**conn_config)
 
         if client_name == "mysql-connector-python":
@@ -233,7 +238,7 @@ def get_conn(self) -> MySQLConnectionTypes:
                     "'mysql-connector-python'. Warning! It might cause dependency conflicts."
                 )
 
-            conn_config = self._get_conn_config_mysql_connector_python(conn)  # type: ignore[arg-type]
+            conn_config = self._get_conn_config_mysql_connector_python(conn)
             return mysql.connector.connect(**conn_config)
 
         raise ValueError("Unknown MySQL client name provided!")
@@ -253,7 +258,7 @@ def bulk_load(self, table: str, tmp_file: str) -> None:
             (tmp_file,),
         )
         conn.commit()
-        conn.close()  # type: ignore[misc]
+        conn.close()
 
     def bulk_dump(self, table: str, tmp_file: str) -> None:
         """Dump a database table into a tab-delimited file."""
@@ -270,7 +275,7 @@ def bulk_dump(self, table: str, tmp_file: str) -> None:
             (tmp_file,),
         )
         conn.commit()
-        conn.close()  # type: ignore[misc]
+        conn.close()
 
     @staticmethod
     def _serialize_cell(cell: object, conn: Connection | None = None) -> Any:
@@ -337,7 +342,7 @@ def bulk_load_custom(
 
         cursor.close()
         conn.commit()
-        conn.close()  # type: ignore[misc]
+        conn.close()
 
     def get_openlineage_database_info(self, connection):
         """Return MySQL specific information for OpenLineage."""