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set proper sys.argv[0] for subcommand #248

merged 3 commits into from Nov 4, 2021


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In openSUSE/libalternatives#11 we noticed that jupyter subcommand calls jupyter-subcommand with an argv[0]=subcommand instead of the proper executable name jupyter-subcommand.

Most subcommands do not care, because the first thing they do, is strip sys.argv[0] from the parsing:

if argv is None:
argv = sys.argv[1:]
if argv:
subc = self._find_subcommand(argv[0])

From the Python Doc: os.execv*():

In either case, the arguments to the child process should start with the name of the command being run, but this is not enforced.

So nothing mandates argv[0] to be set to the name, but it is good practise and libalternatives relies on it.

You already do the same for subcommands of JupyterApps:

def start(self):
"""Start the whole thing"""
if self.subcommand:
os.execv(self.subcommand, [self.subcommand] + self.argv[1:])

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Thanks! Can we also add a test in to make sure we don't break this in the future?

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@bnavigator - does the test I added look good to you?

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@jasongrout jasongrout merged commit 2ccb576 into jupyter:master Nov 4, 2021
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2 participants