Prevent softpack-core --help hanging forever
#35
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This prevents the thread from blocking application exit. It also means the thread can be shut down abruptly, without resources (like open files) being released, but that's ok – at most it will leave a temporary directory lying around in /tmp. (And, in fact, it currently never cleans up its temporary directories anyway.)
Typer runs Click commands in "standalone mode": > Click will then handle exceptions and convert them into error messages > and the function will never return but shut down the interpreter. so any code after the call to Typer will never actually be executed. The `assert False` is required to convince mypy that we know Typer will never return. Related: fastapi/typer#129
Codecov ReportAttention:
Additional details and impacted files@@ Coverage Diff @@
## develop #35 +/- ##
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- Coverage 65.37% 65.29% -0.09%
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Files 16 16
Lines 774 775 +1
Branches 131 131
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Hits 506 506
- Misses 261 262 +1
Partials 7 7 ☔ View full report in Codecov by Sentry. |
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The package list retrieval thread would previously run forever and prevent the interpreter from shutting down. This PR marks that thread as a daemon thread, so the interpreter will abruptly terminate it whenever the rest of the application exits (since all that thread does is "
git cloneinto a temporary directory" and "runspack list", that's fine).There was code in
Application.mainthat was intended to prevent this from happening (by cancelling the thread onceself.commands()returns), but Typer uses Click in "standalone mode" which means thatself.commands()doesn't return, it just exits. So the main thread would exit, and the entire application would then wait for the package list retrieval thread to exit, but with no main thread to tell it to exit, it would run forever.