[WB-6500] fixes CondaEnvExportError by redirecting stderr

[charlesfrye]

https://wandb.atlassian.net/browse/WB-6500

Description

When users have conda installed on their system and are in the root directory, our conda env export call to produce an environment.yml fails and prints an error. This is despite the fact that we try to catch exceptions with except Exception, because the error occurs in a subprocess call.

This issue can happen in, e.g., the environment of JarvisLabs, which provides cloud GPUs and credits and may be a first W&B experience for some users. See JIRA for more context.

The issue occurs right when you call wandb.init, so it's not putting our best foot forward!

Testing

I checked that, post-fix, the error on wandb.init call no longer occurs in an environment on JarvisLabs.

I also checked that the CondaEnvExportError is still triggered by a bare conda env export call in the same environment.

The solution uses subprocess.DEVNULL, which is Python>=3.3.

Release Notes

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[codecov]

Codecov Report

Merging #2814 (9c67e49) into master (50c7895) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master    #2814   +/-   ##
=======================================
  Coverage   76.29%   76.29%           
=======================================
  Files         178      178           
  Lines       26548    26548           
=======================================
+ Hits        20254    20256    +2     
+ Misses       6294     6292    -2     

Flag	Coverage Δ
functest	51.06% <0.00%> (+<0.01%)	⬆️
unittest	70.49% <100.00%> (+0.02%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
wandb/sdk/internal/meta.py	90.18% <100.00%> (+3.06%)	⬆️
wandb/sdk/internal/file_stream.py	82.26% <0.00%> (-1.51%)	⬇️
wandb/sdk/lib/redirect.py	86.53% <0.00%> (-0.18%)	⬇️
wandb/sdk/lib/git.py	75.86% <0.00%> (ø)
wandb/sdk/internal/sender.py	91.79% <0.00%> (+0.13%)	⬆️
wandb/filesync/step_prepare.py	94.28% <0.00%> (+1.42%)	⬆️

[adrnswanberg]

Thanks for fixing!

[vanpelt]

🔥