"ERROR: unable to rename file" in a Dropbox folder

[shaicoleman]

If the current directory is a Dropbox synced folder, and the title contains unicode characters, the download will fail with "ERROR: unable to rename file: [Errno 2] No such file or directory"

$ cd ~/Dropbox/myfolder
$ youtube-dl --verbose 'https://www.youtube.com/watch?v=cXRByrzCNOM'
[debug] System config: []
[debug] User config: []
[debug] Custom config: []
[debug] Command-line args: ['--verbose', 'https://www.youtube.com/watch?v=cXRByrzCNOM']
[debug] Encodings: locale UTF-8, fs utf-8, out UTF-8, pref UTF-8
[debug] youtube-dl version 2018.11.03
[debug] Python version 3.6.6 (CPython) - Linux-4.15.0-38-generic-x86_64-with-Ubuntu-18.04-bionic
[debug] exe versions: ffmpeg 3.4.4-0ubuntu0.18.04.1, ffprobe 3.4.4-0ubuntu0.18.04.1
[debug] Proxy map: {}
[youtube] cXRByrzCNOM: Downloading webpage
[youtube] cXRByrzCNOM: Downloading video info webpage
[youtube] {18} signature length 42.43, html5 player vflKOteNp [SNIPPED REPEATING LINE]
[debug] Default format spec: bestvideo+bestaudio/best
WARNING: Requested formats are incompatible for merge and will be merged into mkv.
[debug] Invoking downloader on 'https://r5---sn-q0cedn7s.googlevideo.com/videoplayback?key=yt6&c=WEB&ei=TTXgW72UEozeVo2KhJAK&clen=5585913&aitags=133%2C134%2C135%2C136%2C137%2C160%2C242%2C243%2C244%2C247%2C248%2C278&source=youtube&expire=1541441965&ipbits=0&lmt=1502037969877319&gir=yes&mime=video%2Fmp4&requiressl=yes&keepalive=yes&fvip=5&id=o-AM-qMSaGVDuy100t6XJZ49ri8O2X17K-lNVeEh-FjOON&sparams=aitags%2Cclen%2Cdur%2Cei%2Cgir%2Cid%2Cinitcwndbps%2Cip%2Cipbits%2Citag%2Ckeepalive%2Clmt%2Cmime%2Cmm%2Cmn%2Cms%2Cmv%2Cpl%2Crequiressl%2Csource%2Cexpire&itag=137&ms=au%2Conr&initcwndbps=1457500&mv=m&dur=274.524&mt=1541420255&pl=17&mn=sn-q0cedn7s%2Csn-aigzrn7d&ip=80.111.206.167&mm=31%2C26&signature=952B8169166467215F77D437A50D02C1E3ED3C81.3DB00B639FCE6DB1297569D953B3228DB5D8EB87&ratebypass=yes'
[download] Destination: Trio Lubião - Pássaro Preto (Forró Stream)-cXRByrzCNOM.f137.mp4
[download] 100.0% of 5.33MiB at  6.65MiB/s ETA 00:00ERROR: unable to rename file: [Errno 2] No such file or directory: 'Trio Lubião - Pássaro Preto (Forró Stream)-cXRByrzCNOM.f137.mp4.part' -> 'Trio Lubião - Pássaro Preto (Forró Stream)-cXRByrzCNOM.f137.mp4'
Traceback (most recent call last):
  File "/home/shai/.local/lib/python3.6/site-packages/youtube_dl/downloader/common.py", line 200, in try_rename
    os.rename(encodeFilename(old_filename), encodeFilename(new_filename))
FileNotFoundError: [Errno 2] No such file or directory: 'Trio Lubião - Pássaro Preto (Forró Stream)-cXRByrzCNOM.f137.mp4.part' -> 'Trio Lubião - Pássaro Preto (Forró Stream)-cXRByrzCNOM.f137.mp4'

After running the youtube-dl command a second time, a filename containing "Unicode Encoding Conflict" appears in the Dropbox folder, which might give a hint on what's causing the issue:

$ youtube-dl --verbose 'https://www.youtube.com/watch?v=cXRByrzCNOM'
$ youtube-dl --verbose 'https://www.youtube.com/watch?v=cXRByrzCNOM'
$ ls
'Trio Lubião - Pássaro Preto (Forró Stream)-cXRByrzCNOM.f137.mp4.part'
'Trio Lubião - Pássaro Preto (Forró Stream)-cXRByrzCNOM.f137.mp4 (Unicode Encoding Conflict).part'

Possible way to fix this issue is to create the temporary files inside the tmp folder instead of the current directory.
Another workaround is to use --restrict-filenames
Might also be some bug with Dropbox

System information:

youtube-dl: 2018.11.03
OS: Ubuntu 18.04 x64
Python: 3.6.6
Filesystem: ext4
ffmpeg: 3.4.4 (from the bionic repo)
kernel: 4.15.0 (linux-generic from the bionic repo)

[dstftw]

Blame Dropbox for that. What you can do is not to write in Dropbox folder or use --restrict-filenames. Writing in temp is not an option since it's not a temp file in the first place.