User-local Bash completions not loading

[Lucas Sandery]

I'm on Noble. I don't believe there's anything special about my environment with respect to Bash completions. I had pipx installed to prevent conflicts with the system python, which brings in the python3-argcomplete package. I've temporarily removed the former but kept the latter, in order to investigate my problem.

When argcomplete is installed, completions in ~/.local/share/bash-completion/completions/ do not load or run. Their underscore-prefixed functions do not appear in the environment. To test, I created a file there for the non-existent command "zz", with these contents:

_zz () {
    COMPREPLY=($(compgen -W 'foo bar baz qux' -- "$2"))
} && complete -F _zz zz

At a fresh Bash prompt, I type "zz " then hit Tab. It will only complete filenames from the current dir, not from the specified argument set. Under "bash -x", the trace after doing so begins with this:

+ [[ -n '' ]]
+ local _BASH_REMATCH=
+ local executable=
+ req_argv=()
+ local req_argv
+ [[ -z '' ]]
+ executable=zz
+ req_argv=("" "${COMP_WORDS[@]:1}")
+ __python_argcomplete_expand_tilde_by_ref executable
...

If I uninstall the argcomplete package and do the same, fresh prompt each time, my completions work again. I can reliably toggle this behaviour by reinstalling & uninstalling it. The successful trace begins with this:

+ local cmd=zz
+ __load_completion zz
+ dirs=('/home/l/.local/share/bash-completion/completions')
+ local -a dirs
...