Exceptions breaks iteration loops.

[kilsbo]

I am using the following code:

      val it = CSVReader.open(file).iterator
      val line = it.next
      println("format: " + line)

      var cont = true

      while (it.hasNext) {

        try {
          val line = it.next

          //println(line)

        }
        catch {
          case e: Exception => {
            println("Line failed")
            println(e.getMessage)
            errcnt += 1
          }
        }
      }

When the iterator hits a malformed CSV-line, it throws an Exception. However, it does it already on the it.hasNext call, making it impossible for me to skip that line and continue.

I tried to use a boolean in the where-clause, but it seems that the faulty line breaks the iterator so I cannot use that approach either.

Are there other ways to do this, or do we need a fix here?

[kilsbo]

Ok so I was wrong on one thing, it does continue after a failed it.hasNext, however, would like for it to not throw an exception on it.hasNext, but on it.next.

[mossprescott]

I'm believe I'm seeing another manifestation of this, which is that toStream doesn't behave consistently when parse failures occur. The first attempt to read the stream throws an exception, and then subsequent attempts behave as if the stream just ended before the bad record.

For example:

scala> import com.github.tototoshi.csv._
import com.github.tototoshi.csv._

scala> val s = CSVReader.open(new java.io.StringReader("a,b\n1,2\n,\"\n")).toStream
s: Stream[List[String]] = Stream(List(a, b), ?)

scala> s.toList
com.github.tototoshi.csv.MalformedCSVException: Malformed Input!: Some(,"
)
  at com.github.tototoshi.csv.CSVReader.parseNext$1(CSVReader.scala:39)

scala> s.toList
res1: List[List[String]] = List(List(a, b), List(1, 2))

I'm not sure if it's generally acceptable for Streams to throw exceptions, but certainly it seems like it should do so consistently. Alternatively, return Either[SomeError, List[String]] or use a different lazy sequence that supports failure.