fix current thread join runtime error

[chengs]

This PR fixes #613

Explain:
When exit, a TMonitor thread wants to join itself, but if it cannot do that if it is the current thread, which will raise an error as in File "/Users/guchen/anaconda3/lib/python3.6/threading.py"

if self is current_thread():
            raise RuntimeError("cannot join current thread")

I just add one line to check whether it is the current thread. See #613 for more discussion. In fact, it rarely happens. For instance, in a case that the main thread is killed by accident (eg, by errors) and only the TMonitor thread remains.

Code to reproduce the error

from time import sleep
from tqdm.auto import tqdm

for i in tqdm(range(10)):
    if i == 3:
        sleep(20)
        raise Exception("Wrong!")
    else:
        sleep(1)

[codecov-io]

Codecov Report

Merging #641 into master will decrease coverage by 0.13%.
The diff coverage is 66.66%.

@@            Coverage Diff             @@
##           master     #641      +/-   ##
==========================================
- Coverage   98.78%   98.65%   -0.14%     
==========================================
  Files          10       10              
  Lines         743      744       +1     
  Branches      132      133       +1     
==========================================
  Hits          734      734              
  Misses          5        5              
- Partials        4        5       +1

[iainsmith]

Hit this today when streaming downloads with requests.

[jlmeunier]

Thanks for this fix (worked for me, on this particular issue)

[chengs]

ping...

[EKami]

I don't get it, why this PR wasn't merged? Is this bug fixed? I just ran into it today but I'm not sure I was on the latest version of tqdm. I'll relaunch the process with the last version this time.

[Limmen]

This bug still occurs on master and latest release, had to downgrade to 4.21.0 to avoid it. What's the status on this?

[casperdcl]

This PR was merged in 6081329, fixing #613. if you're still getting an error which you believe is #613, please post the error output in #613...