In SparkBuild.scala, a variable 'scalaBinaryVersion' is hardcoded as '2.12'.
So, an environment variable 'SPARK_SCALA_VERSION' is also to be '2.12'.
This issue causes some test suites (e.g. SparkSubmitSuite) to be error.
===== TEST OUTPUT FOR o.a.s.deploy.SparkSubmitSuite: 'user classpath first in driver' =====
20/10/02 08:55:30.234 redirect stderr for command /home/kou/work/oss/spark-scala-2.13/bin/spark-submit INFO Utils: Error: Could not find or load m
ain class org.apache.spark.launcher.Main
20/10/02 08:55:30.235 redirect stderr for command /home/kou/work/oss/spark-scala-2.13/bin/spark-submit INFO Utils: /home/kou/work/oss/spark-scala-
2.13/bin/spark-class: line 96: CMD: bad array subscript
The reason of this error is that environment variables 'SPARK_JARS_DIR' and 'LAUNCH_CLASSPATH' is defined in bin/spark-class as follows.