I have a connection "spark2_default" :
|Conn Id||Conn Type||Host||Port||Is Encrypted||Is Extra Encrypted||Extra|
Extra contains 'spark-binary' key that was use by airflow 1.10.2 to choose spark-submit operator. But in version 1.10.6 this config is ignore.
I think that , in class SparkSubmitOperator in init function they has a default value "spark-submit" for spark_binary parameter.
Therefore in class SparkSubmitHook when we control if spark_binary is empty it can't be.