[SPARK-26076] Revise ambiguous error message from load-spark-env.sh

• Type: Improvement
• Status: Resolved
• Priority: Trivial
• Resolution: Fixed
• Affects Version/s: 3.0.0
• Fix Version/s: 3.0.0
• Component/s: Build
• Assignee: Gengliang Wang
• Reporter: Gengliang Wang
• Created: 15/Nov/18 15:48
• Updated: 20/Nov/18 14:30
• Resolved: 20/Nov/18 14:30

Description

When I try to run scripts (e.g. `./sbin/start-history-server.sh -h` in latest master, I got such error:
```
Presence of build for multiple Scala versions detected.

Either clean one of them or, export SPARK_SCALA_VERSION in spark-env.sh.
```

The error message is quite confusing and there is no `spark-env.sh` in our code base.
As now with https://github.com/apache/spark/pull/22967, we can revise the error message as following:

```
Presence of build for both scala versions(SCALA 2.11 and SCALA 2.12) detected.
Either clean one of them or, export SPARK_SCALA_VERSION=2.12 in load-spark-env.sh.
```

Issue Links

• links to: [Github] Pull Request #23049 (gengliangwang)