FileIO.toFile does not truncate existing file

[Enno]

Hi Hakkars,

The file my stream created started to look rather funny so I had to dig a bit.

The API docs for FileIO.toFile state it "Overwrites existing files by default.", but that becomes a bit to literally with the default options.

(see http://doc.akka.io/api/akka/2.5/akka/stream/scaladsl/FileIO$.html )

  def toPath(f: Path, options: Set[StandardOpenOption] = Set(WRITE, CREATE))

For an existing file with options WRITE, CREATE the new content will overwrite the file's content from the file's start, but not truncate the old contents. So in case less content is written in later runs the old content will follow the new content. 

Wouldn't it be more intuitive (and more according to the docs) to use WRITE, CREATE, TRUNCATE_EXISTING as default options?

(see https://docs.oracle.com/javase/8/docs/api/java/nio/file/StandardOpenOption.html )

Cheers,

Enno.

[Patrik Nordwall]

Wow, not truncating would be very confusing. Please open a PR.

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[Konrad Malawski]

Great catch, you're absolutely right. Please open a PR, thanks!

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[Enno]

Please consider PR #22772

https://github.com/akka/akka/pull/22772

Cheers,

Enno.

Am Freitag, 21. April 2017 15:39:32 UTC+2 schrieb Patrik Nordwall:

Wow, not truncating would be very confusing. Please open a PR.

On Fri, Apr 21, 2017 at 3:36 PM, Enno <enno....@gmail.com> wrote:

Hi Hakkars,

The file my stream created started to look rather funny so I had to dig a bit.

The API docs for FileIO.toFile state it "Overwrites existing files by default.", but that becomes a bit to literally with the default options.

(see http://doc.akka.io/api/akka/2.5/akka/stream/scaladsl/FileIO$.html )

  def toPath(f: Path, options: Set[StandardOpenOption] = Set(WRITE, CREATE))

For an existing file with options WRITE, CREATE the new content will overwrite the file's content from the file's start, but not truncate the old contents. So in case less content is written in later runs the old content will follow the new content. 

Wouldn't it be more intuitive (and more according to the docs) to use WRITE, CREATE, TRUNCATE_EXISTING as default options?

(see https://docs.oracle.com/javase/8/docs/api/java/nio/file/StandardOpenOption.html )

Cheers,

Enno.

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>>>>>>>>>> Read the docs: http://akka.io/docs/
>>>>>>>>>> Check the FAQ: http://doc.akka.io/docs/akka/current/additional/faq.html
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