Latest version: "Signature extraction failed: Traceback" and "Unsupported JS expression."

[sawyer07]

youtube-dl --version yields 2020.01.24 - latest version. Curiously, several recent posts of similar nature have been closed and flagged for "outdated version" without explanation.

Example affected video: https://www.youtube.com/watch?v=I8KSAtos-dk playable in browser.

Checklist (latest version confirmed)

• I'm reporting a broken site support issue
• I've verified that I'm running the latest youtube-dl version 2020.01.24
• I've checked that all provided URLs are alive and playable in a browser
• I've checked that all URLs and arguments with special characters are properly quoted or escaped
• I've searched the bugtracker for similar bug reports including closed ones
• I've read bugs section in FAQ

Verbose log

~>youtube-dl --verbose 'https://www.youtube.com/watch?v=I8KSAtos-dk' 
[debug] System config: [] 
[debug] User config: [] 
[debug] Custom config: [] 
[debug] Command-line args: ['--verbose', 'https://www.youtube.com/watch?v=I8KSAtos-dk'] 
[debug] Encodings: locale UTF-8, fs utf-8, out UTF-8, pref UTF-8 
[debug] youtube-dl version 2019.12.25 
[debug] Python version 3.6.9 (CPython) - Linux-4.15.0-64-generic-x86_64-with-LinuxMint-19-tara 
[debug] exe versions: ffmpeg 3.4.6, ffprobe 3.4.6 
[debug] Proxy map: {} 
[youtube] I8KSAtos-dk: Downloading webpage 
[youtube] I8KSAtos-dk: Downloading video info webpage 
[youtube] {18} signature length 106, html5 player vfl1GpCbm 
[youtube] I8KSAtos-dk: Downloading player https://www.youtube.com/yts/jsbin/player_ias-vfl1GpCbm/en_US/base.js 
ERROR: Signature extraction failed: Traceback (most recent call last): 
  File "/home/oarion7/.local/lib/python3.6/site-packages/youtube_dl/extractor/youtube.py", line 1384, in _decrypt_signature 
    video_id, player_url, s 
  File "/home/oarion7/.local/lib/python3.6/site-packages/youtube_dl/extractor/youtube.py", line 1297, in _extract_signature_function 
    cache_res = res(test_string) 
  File "/home/oarion7/.local/lib/python3.6/site-packages/youtube_dl/extractor/youtube.py", line 1360, in <lambda> 
    return lambda s: initial_function([s]) 
  File "/home/oarion7/.local/lib/python3.6/site-packages/youtube_dl/jsinterp.py", line 258, in resf 
    res, abort = self.interpret_statement(stmt, local_vars) 
  File "/home/oarion7/.local/lib/python3.6/site-packages/youtube_dl/jsinterp.py", line 56, in interpret_statement 
    v = self.interpret_expression(expr, local_vars, allow_recursion) 
  File "/home/oarion7/.local/lib/python3.6/site-packages/youtube_dl/jsinterp.py", line 92, in interpret_expression 
    m.group('expr'), local_vars, allow_recursion - 1) 
  File "/home/oarion7/.local/lib/python3.6/site-packages/youtube_dl/jsinterp.py", line 189, in interpret_expression 
    m.group('x'), local_vars, allow_recursion - 1) 
  File "/home/oarion7/.local/lib/python3.6/site-packages/youtube_dl/jsinterp.py", line 56, in interpret_statement 
    v = self.interpret_expression(expr, local_vars, allow_recursion) 
  File "/home/oarion7/.local/lib/python3.6/site-packages/youtube_dl/jsinterp.py", line 211, in interpret_expression 
    raise ExtractorError('Unsupported JS expression %r' % expr) 
youtube_dl.utils.ExtractorError: Unsupported JS expression '[1376500448,'; please report this issue on https://yt-dl.org/bug .... 
 (caused by ExtractorError("Unsupported JS expression '[1376500448,'; please report this issue on https://yt-dl.org/bug .... 
Traceback (most recent call last): 
  File "/home/oarion7/.local/lib/python3.6/site-packages/youtube_dl/extractor/youtube.py", line 1384, in _decrypt_signature 
    video_id, player_url, s 
  File "/home/oarion7/.local/lib/python3.6/site-packages/youtube_dl/extractor/youtube.py", line 1297, in _extract_signature_function 
    cache_res = res(test_string) 
  File "/home/oarion7/.local/lib/python3.6/site-packages/youtube_dl/extractor/youtube.py", line 1360, in <lambda> 
    return lambda s: initial_function([s]) 
  File "/home/oarion7/.local/lib/python3.6/site-packages/youtube_dl/jsinterp.py", line 258, in resf 
    res, abort = self.interpret_statement(stmt, local_vars) 
  File "/home/oarion7/.local/lib/python3.6/site-packages/youtube_dl/jsinterp.py", line 56, in interpret_statement 
    v = self.interpret_expression(expr, local_vars, allow_recursion) 
  File "/home/oarion7/.local/lib/python3.6/site-packages/youtube_dl/jsinterp.py", line 92, in interpret_expression 
    m.group('expr'), local_vars, allow_recursion - 1) 
  File "/home/oarion7/.local/lib/python3.6/site-packages/youtube_dl/jsinterp.py", line 189, in interpret_expression 
    m.group('x'), local_vars, allow_recursion - 1) 
  File "/home/oarion7/.local/lib/python3.6/site-packages/youtube_dl/jsinterp.py", line 56, in interpret_statement 
    v = self.interpret_expression(expr, local_vars, allow_recursion) 
  File "/home/oarion7/.local/lib/python3.6/site-packages/youtube_dl/jsinterp.py", line 211, in interpret_expression 
    raise ExtractorError('Unsupported JS expression %r' % expr) 
youtube_dl.utils.ExtractorError: Unsupported JS expression '[1376500448,'; please report this issue on https://yt-dl.org/bug ....  
Traceback (most recent call last): 
  File "/home/oarion7/.local/lib/python3.6/site-packages/youtube_dl/extractor/youtube.py", line 1384, in _decrypt_signature 
    video_id, player_url, s 
  File "/home/oarion7/.local/lib/python3.6/site-packages/youtube_dl/extractor/youtube.py", line 1297, in _extract_signature_function 
    cache_res = res(test_string) 
  File "/home/oarion7/.local/lib/python3.6/site-packages/youtube_dl/extractor/youtube.py", line 1360, in <lambda> 
    return lambda s: initial_function([s]) 
  File "/home/oarion7/.local/lib/python3.6/site-packages/youtube_dl/jsinterp.py", line 258, in resf 
    res, abort = self.interpret_statement(stmt, local_vars) 
  File "/home/oarion7/.local/lib/python3.6/site-packages/youtube_dl/jsinterp.py", line 56, in interpret_statement 
    v = self.interpret_expression(expr, local_vars, allow_recursion) 
  File "/home/oarion7/.local/lib/python3.6/site-packages/youtube_dl/jsinterp.py", line 92, in interpret_expression 
    m.group('expr'), local_vars, allow_recursion - 1) 
  File "/home/oarion7/.local/lib/python3.6/site-packages/youtube_dl/jsinterp.py", line 189, in interpret_expression 
    m.group('x'), local_vars, allow_recursion - 1) 
  File "/home/oarion7/.local/lib/python3.6/site-packages/youtube_dl/jsinterp.py", line 56, in interpret_statement 
    v = self.interpret_expression(expr, local_vars, allow_recursion) 
  File "/home/oarion7/.local/lib/python3.6/site-packages/youtube_dl/jsinterp.py", line 211, in interpret_expression 
    raise ExtractorError('Unsupported JS expression %r' % expr) 
youtube_dl.utils.ExtractorError: Unsupported JS expression '[1376500448,'; please report this issue on https://yt-dl.org/bug .... 
During handling of the above exception, another exception occurred: 
Traceback (most recent call last): 
  File "/home/oarion7/.local/lib/python3.6/site-packages/youtube_dl/YoutubeDL.py", line 796, in extract_info 
    ie_result = ie.extract(url) 
  File "/home/oarion7/.local/lib/python3.6/site-packages/youtube_dl/extractor/common.py", line 530, in extract 
    ie_result = self._real_extract(url) 
  File "/home/oarion7/.local/lib/python3.6/site-packages/youtube_dl/extractor/youtube.py", line 2047, in _real_extract 
    encrypted_sig, video_id, player_url, age_gate) 
  File "/home/oarion7/.local/lib/python3.6/site-packages/youtube_dl/extractor/youtube.py", line 1394, in _decrypt_signature 
    'Signature extraction failed: ' + tb, cause=e) 
youtube_dl.utils.ExtractorError: Signature extraction failed: Traceback (most recent call last): 
  File "/home/oarion7/.local/lib/python3.6/site-packages/youtube_dl/extractor/youtube.py", line 1384, in _decrypt_signature 
    video_id, player_url, s 
  File "/home/oarion7/.local/lib/python3.6/site-packages/youtube_dl/extractor/youtube.py", line 1297, in _extract_signature_function 
    cache_res = res(test_string) 
  File "/home/oarion7/.local/lib/python3.6/site-packages/youtube_dl/extractor/youtube.py", line 1360, in <lambda> 
    return lambda s: initial_function([s]) 
  File "/home/oarion7/.local/lib/python3.6/site-packages/youtube_dl/jsinterp.py", line 258, in resf 
    res, abort = self.interpret_statement(stmt, local_vars) 
  File "/home/oarion7/.local/lib/python3.6/site-packages/youtube_dl/jsinterp.py", line 56, in interpret_statement 
    v = self.interpret_expression(expr, local_vars, allow_recursion) 
  File "/home/oarion7/.local/lib/python3.6/site-packages/youtube_dl/jsinterp.py", line 92, in interpret_expression 
    m.group('expr'), local_vars, allow_recursion - 1) 
  File "/home/oarion7/.local/lib/python3.6/site-packages/youtube_dl/jsinterp.py", line 189, in interpret_expression 
    m.group('x'), local_vars, allow_recursion - 1) 
  File "/home/oarion7/.local/lib/python3.6/site-packages/youtube_dl/jsinterp.py", line 56, in interpret_statement 
    v = self.interpret_expression(expr, local_vars, allow_recursion) 
  File "/home/oarion7/.local/lib/python3.6/site-packages/youtube_dl/jsinterp.py", line 211, in interpret_expression 
    raise ExtractorError('Unsupported JS expression %r' % expr) 
youtube_dl.utils.ExtractorError: Unsupported JS expression '[1376500448,'; please report this issue on https://yt-dl.org/bug .... 

Description

Download of certain videos yields python string extraction errors. "ERROR: Signature extraction failed: Traceback" and "Unsupported JS expression."

[forresthopkinsa]

I was having this error, I upgraded to 2020.01.24 (literally just downloaded the binary in the Github release and ran it in the same directory) and the problem went away.