ui: pbar during md5 calc doesn't need to be multithreaded

[Suor]

The "Mutithreaded" prefix is confusing, also jumping through screen doesn't work with redirection well.

[shcheklein]

💯 on this!

[casperdcl]

@Suor just to confirm for other multi-threaded commands is screen still giving you trouble?

perhaps this is tqdm/tqdm#798 - you may need screen -U

[Suor]

Never ran dvc in screen. I had, however, similar problem when redirecting dvc output, special line up sequence got swallowed somewhere in the process.

[efiop]

Btw, @casperdcl , just wondering, does tqdm use is_tty to avoid printing some things when it is not using a console?

[casperdcl]

@efiop no, that would be an interesting feature request. The thing is if you pipe output to a file and then cat the file, often the control characters are parsed properly.

[efiop]

@casperdcl Yeah, but you usually don't cat if you redirect it to a file :) If you are redirecting, then you want a log file to read later(to grep, to vim or whatever), which doesn't need control chars and they might even be harmful. I'm pretty sure I've seen tools use isatty to distinguish those cases a lot. Our old progress bar did that too if I recall correctly. The downside of that approach is that now you suddenly have two types of outputs, which might cause some things to not get enough testing. So there are pros and cons to both approaches, for sure.

[casperdcl]

nvm correction this was solved way back in tqdm/tqdm#281 - it's just not propagated to dvc.