Github user srowen commented on a diff in the pull request:
https://github.com/apache/spark/pull/14332#discussion_r71993270
--- Diff:
examples/src/main/scala/org/apache/spark/examples/ml/DataFrameExample.scala ---
@@ -54,14 +54,13 @@ object DataFrameExample {
}
}
- parser.parse(args, defaultParams).map { params =>
- run(params)
- }.getOrElse {
- sys.exit(1)
+ parser.parse(args, defaultParams) match {
+ case Some(params) => run(params)
+ case _ => sys.exit(1)
}
--- End diff --
The issue here is `map`. On style: why would you use `map` with an
expression whose type is `Unit`? theoretically that's never correct. (It's a
warning in IJ.) The question isn't readability.
The deeper issue turns up with view-like collections, where the `map` body
won't actually execute at all. I don't know if that type of problem is actually
possible with `Option` though. I figured it can't hurt to foreclose that
possibility entirely with a more explicit construct.
`fold` is less obvious and has the same theoretical problem. I would not
use that pattern.
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