Streamlink is starting download before user's response for file overwrite #4248
Description
Checklist
- This is a bug report and not a different kind of issue
- I have read the contribution guidelines
- I have checked the list of open and recently closed bug reports
- I have checked the commit log of the master branch
Streamlink version
Latest stable release
Description
When file output option -o is used to an existing file, Streamlink prints confirmation message for file overwrite and asks for user's response.
However, before the response, Streamlink has already started downloading and continues. If the user responds with "n", this will result in a waste of bandwidth. It can also be confusing when used with -l debug, as the debug messages are printed as if confirmation is ignored.
It would be better to check the output file before opening the stream.
In the debug log below, I responded with "n" after [stream.segmented][debug] Closing writer thread message.
Debug log
[cli][debug] OS: macOS 10.12.6
[cli][debug] Python: 3.9.9
[cli][debug] Streamlink: 3.0.3
[cli][debug] Requests(2.26.0), Socks(1.7.1), Websocket(1.2.3)
[cli][debug] Arguments:
[cli][debug] url=https://www.dailymotion.com/video/x853fvr
[cli][debug] stream=['480p']
[cli][debug] --loglevel=debug
[cli][debug] --output=video.ts
[cli][debug] --hls-duration=20
[cli][info] Found matching plugin dailymotion for URL https://www.dailymotion.com/video/x853fvr
[plugins.dailymotion][debug] Found media ID: x853fvr
[utils.l10n][debug] Language code: en_US
[cli][info] Available streams: 112p_alt (worst), 112p, 184p_alt, 184p, 288p_alt, 288p, 480p_alt, 480p, 720p_alt, 720p, 1080p_alt, 1080p (best)
[cli][info] Opening stream: 480p (hls)
[stream.hls][debug] Reloading playlist
[cli][debug] Pre-buffering 8192 bytes
[stream.hls][debug] First Sequence: 0; Last Sequence: 53
[stream.hls][debug] Start offset: 0; Duration: 20; Start Sequence: 0; End Sequence: 53
[stream.hls][debug] Adding segment 0 to queue
[stream.hls][debug] Adding segment 1 to queue
[stream.hls][debug] Adding segment 2 to queue
[stream.hls][debug] Adding segment 3 to queue
[stream.hls][debug] Adding segment 4 to queue
[stream.hls][debug] Adding segment 5 to queue
[stream.hls][debug] Adding segment 6 to queue
[stream.hls][info] Stopping stream early after 20
[stream.segmented][debug] Closing worker thread
[stream.hls][debug] Segment 0 complete
[cli][debug] Checking file output
File video.ts already exists! Overwrite it? [y/N] [stream.hls][debug] Segment 1 complete
[stream.hls][debug] Segment 2 complete
[stream.hls][debug] Segment 3 complete
[stream.hls][debug] Segment 4 complete
[stream.hls][debug] Segment 5 complete
[stream.hls][debug] Segment 6 complete
[stream.segmented][debug] Closing writer thread
n
[cli][info] Closing currently open stream...