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Merged
efiop merged 1 commit into from
Mar 17, 2023
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close streams #9204

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1 change: 1 addition & 0 deletions dvc/daemon.py
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Original file line number Diff line number Diff line change
Expand Up @@ -82,6 +82,7 @@ def _spawn_posix(cmd, env):
sys.stdin.close()
sys.stdout.close()
sys.stderr.close()
os.closerange(0, 3)
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@efiop efiop Mar 17, 2023

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Hm, this line fixes the problem? Usually the first 3 fds are stdin/stdout/stderr, are you sure this line is doing anything?

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@skshetry skshetry Mar 17, 2023

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yes, that's what surprises me. It's as if close() is not working, maybe they are not really closed until the interpreter shuts down? Idk.

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@efiop efiop Mar 17, 2023

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Or maybe stdin/stdout/stderr are not really fds 0, 1, 2 Could you check?

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@skshetry skshetry Mar 17, 2023

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The first thing that I tried to fix this was:

sys.stdin = None
sys.stdout = None
sys.stderr = None

And it magically worked. So I thought maybe there was a garbage collection issue.
But, adding gc.collect() did not fix it. Then I went to os.close() for code clarity. :)

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@skshetry skshetry Mar 17, 2023 •
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Or maybe stdin/stdout/stderr are not really fds 0, 1, 2 Could you check?

No, they are 0, 1, and 2.

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@skshetry skshetry Mar 17, 2023

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Tbh i don't know what I am doing here. I am also surprised that this fixes the issue. :)

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@efiop efiop Mar 17, 2023

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Looks like you are not first to run into this https://code.activestate.com/recipes/186101-really-closing-stdin-stdout-stderr/

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@efiop efiop Mar 17, 2023

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So looks like sys.* is python level and doesn't necessarily close underlying filedescriptors. I guess that explains this change.

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@skshetry skshetry Mar 17, 2023

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hmm, I searched everywhere but could not get a hint. Thank you for the link. 🙏🏼


if platform.system() == "Darwin":
# workaround for MacOS bug
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