Enforce prevention downloading same file

[brutalcrozt]

Checklist

• I'm reporting a feature request
• I've verified that I'm running youtube-dl version 2019.08.13
• I've searched the bugtracker for similar feature requests including closed ones

I am not sure if this is feature request, it's 2019.07.30 that i use

this is the full info

[debug] System config: []
[debug] User config: []
[debug] Custom config: []
[debug] Command-line args: [u'-v']
[debug] Encodings: locale UTF-8, fs UTF-8, out UTF-8, pref UTF-8
[debug] youtube-dl version 2019.07.30
[debug] Python version 2.7.12 (CPython) - Linux-4.15.0-58-generic-x86_64-with-LinuxMint-18.3-sylvia
[debug] exe versions: ffmpeg 2.8.15, ffprobe 2.8.15
[debug] Proxy map: {}
Usage: youtube-dl [OPTIONS] URL [URL...]

youtube-dl: error: You must provide at least one URL.

## Description

• What the problem is
  
  It already downloaded the x.webm file, but it repeats download again and unfortunately changes to x.mp4

This one is youtube-dl output-ed to mp3

this one is to re-confirm the youtube-dl output-ed to mp3

• How it could be fixed
  Firstly, it's my suspicion that 1. we do check with the desired vidio.extension. While i am proposing we do check existing downloaded file with only the video name, without extension.
  Also, it should be the same, regardless of the desired file output.
  Having said that, i never know or read about the video or output quality.

1. FYI those above behavior is not use --download-archive option

• How your proposed solution would look like
  Always check existing file first, with file default video name as it's the file name and without the file extension.

Related to point 1, can we just make the default youtube-dl behavior when using --yes-playlist use --download-archive with a default file name. IE playlist_id.txt.

I think it can be tackle down with #16790
not use download archive

[dstftw]

You must use --download-archive for this.

[brutalcrozt]

do you think when using --yes-playlist also involving --download-archive is a bad suggestion?

[dstftw]

It's a very bad suggestion.

[brutalcrozt]

Then you owe me an explanation 😉