Canceling poetry update leaves you with poetry not callable.

$ poetry self update
Updating to 1.0.3
 - Downloading poetry-1.0.3-linux.tar.gz 2%^C

$ poetry self update
Traceback (most recent call last):
  File "/home/user/.poetry/bin/poetry", line 12, in <module>
    from poetry.console import main
ModuleNotFoundError: No module named 'poetry'

• I am on the latest Poetry version.
• I have searched the issues of this repo and believe that this is not a duplicate.
• If an exception occurs when executing a command, I executed it again in debug mode (-vvv option).

• OS version and name:
• Poetry version:
• Link of a Gist with the contents of your pyproject.toml file:

Issue

Start by reproducing the failure with the poetry self update command, then inspect the self-update entry point and how cancellation replaces the installed Poetry files. Done means interrupting an update no longer leaves the poetry command unable to import its package.