Flushing doesn't work

[tomwhoiscontrary]

I would expect this test to pass:

@Test
void flushesALineToTheUnderlyingWriter() throws IOException {
    StringWriter buf = new StringWriter();

    Csv.Writer csvWriter = Csv.Writer.of(Csv.Format.RFC4180, Csv.WriterOptions.DEFAULT, buf);
    csvWriter.writeField("foo");
    csvWriter.writeField("bar");
    csvWriter.writeField("baz");
    csvWriter.writeEndOfLine();
    csvWriter.flush();

    Assertions.assertEquals("foo,bar,baz\n", buf.toString());
}

But it does not.

To actually flush data to the writer, Csv.Writer.Output::flush must be called. But this is only called when the buffer is full, or the output is closed. In particular, Csv.Writer::flush does not call it.

I would also expect this to pass if the StringWriter was wrapped in a BufferedWriter with a very large buffer. That is, Csv.Writer::flush should call Writer::flush, not just write the contents of the internal buffer.

I have a long-running process which slowly writes to a CSV-formatted file. That file is consumed by other processes. It would be very useful to be able to ensure that lines are actually written to the file long before it is closed.

The workaround is to use a disposable Csv.Writer for each line - closing it at the end of the line flushes the buffer.

[charphi]

You are right; that's a bug and it will be fixed in next release.

[charphi]

Done in 08dc604