If bash_completion wasn't installed, _filedir wouldn't be defined which
led to all filename-based completions to error out. Specifically
autocompletion would fail when a filename was expected and when
bash_completion wasn't installed. Now we fall back to `compgen -f` if
_filedir fails. According to _filedir's comments, compgen doesn't
handle files with spaces well, but it is still better to complete most
files than none.
The bash completion seems to be working decently at this point, so I
feel comfortable caching the options output to improve the performance
of the completion.
Right now we are generating the fully option list before doing
anything else. That makes filename completion significantly slower
than it was before, for no gain. It's easy to only generate the
option list when it's actually needed.
I also know I could additionally cache the option list across
invocations, but I'm not doing that yet to make testing easier.
While we've had a zsh completion script for a while, we haven't had
one for bash. This one is reasonably comprehensive, although there are
improvements one could imagine for certain options.
Arthur Williams
Philip Langdale